Publications
164. “Carbon–Nitrogen Bond Formation Using Sodium Hexamethyldisilazide: Solvent-Dependent Reactivities and Mechanisms.” You, Q.; Collum, D. B. J. Am. Chem. Soc. 2023, Article ASAP.
163. “Sodiated Oppolzer Enolates: Solution Structures, Mechanism of Alkylation, and the Origin of Stereoselectivity.” Lui, N. M.; Collum, D. B. Org. Chem. Front. 2023, 10, 4750 – 4757.
162. “Lithiated Oppolzer Enolates: Solution Structures, Mechanism of Alkylation, and the Origin of Stereoselectivity.” Lui, N. M.; MacMillan, S. N.; Collum, D. B. J. Am. Chem. Soc. 2022, 144, 23379 – 23395.
161. “Sodium Isopropyl(trimethylsilyl)amide: A Stable and Highly Soluble Lithium Diisopropylamide Mimic.” Ma, Y.; Lui, N. M.; Keresztes, I.; Woltornist, R. A.; Collum, D. B. J. Org. Chem. 2022, 87, 14223 – 14229.
160. “Ketone Enolization with Sodium Hexamethyldisilazide: Solvent- and Substrate-Dependent E–Z Selectivity and Affiliated Mechanisms.” Woltornist, R. A. and Collum, D. B. J. Am. Chem. Soc. 2021, 143, 17452 – 17464.
159. “Reactions of Sodium Diisopropylamide: Liquid-Phase and Solid–Liquid Phase-Transfer Catalysis by N,N,N′,N″,N″-Pentamethyldiethylenetriamine.” Ma, Y.; Woltornist, R. A.; Algera, R. F.; Collum, D. B. J. Am. Chem. Soc. 2021, 143, 13370 – 13381.
158. “Aggregation and Solvation of Sodium Hexamethyldisilazide: Across the Solvent Spectrum.” Woltornist, R. A. and Collum, D. B. J. Org. Chem. 2021, 86, 2406 – 2422.
157. “Sodium Hexamethyldisilazide: Using 15N–29Si Scalar Coupling to Determine Aggregation and Solvation States.” Woltornist, R. A. and Collum, D. B. J. Am. Chem. Soc. 2020, 142, 6852 – 6855.
156. “Structure, Reactivity, and Synthetic Applications of Sodium Diisopropylamide.” Woltornist, R. A.; Ma, Y.; Algera, R. F.; Zhou, Y; Zhang, Z; Collum, D. B. Synthesis 2020, 52, 1478 – 1497
155. “Disodium Salts of Pseudoephedrine-Derived Myers Enolates: Stereoselectivity and Mechanism of Alkylation” Zhou, Y.; Keresztes, I.; MacMillan, S. N.; Collum, D. B. J. Am. Chem. Soc. 2019, 141, 16865 – 16876.
154. “Enantioselective Alkylation of 2-Alkylpyridines Controlled by Organolithium Aggregation” Gladfelder, J. J.; Ghosh, S.; Podunavac, M.; Cook, A. W.; Ma, Y.; Woltornist, R. A.; Keresztes, I.; Hayton, T. W.; Collum, D. B.; Zakarian, A. J. Am. Chem. Soc. 2019, 141, 15024 – 15028.
Supporting Information: 1, 2, 3
153. “Sodium Diisopropylamide-Mediated Dehydrohalogenations: Influence of Primary- and Secondary-Shell Solvation” Ma, Y.; Algera, R. F.; Woltornist, R. A.; Collum, D. B. J. Org. Chem. 2019, 84, 10860 – 10869.
152. “Wittig Rearrangements of Boron-Based Oxazolidinone Enolates” Zhang, Z. and Collum, D. B. J. Org. Chem. 2019, 84, 10892 – 10900.
151. “Aryl Carbamates: Mechanisms of Orthosodiations and Snieckus–Fries Rearrangements” Ma, Y.; Woltornist, R. A.; Algera, R. F.; Collum, D. B. J. Org. Chem. 2019, 84, 9051 – 9057.
150. “Pseudoephedrine-Derived Myers Enolates: Structures and Influence of Lithium Chloride on Reactivity and Mechanism” Zhou, Y.; Jermaks, J.; Keresztes, I.; MacMillan, S. N.; Collum, D. B. J. Am. Chem. Soc. 2019, 141, 5444 – 5460.
Structure determination videos: 1, 2
149. “Structures and Reactivities of Sodiated Evans Enolates: Role of Solvation and Mixed Aggregation on the Stereochemistry and Mechanism of Alkylations” Zhang, Z. and Collum, D. B. J. Am. Chem. Soc. 2019, 141, 388 – 401.
148. “Case for Lithium Tetramethylpiperidide-Mediated Ortholithiations: Reactivity and Mechanisms” Mack, K. A. and Collum, D. B. J. Am. Chem. Soc. 2018, 140, 4877 — 4883.
147. “Lithium Amino Alkoxide−Evans Enolate Mixed Aggregates: Aldol Addition with Matched and Mismatched Stereocontrol” Jermaks, J.; Tallmadge, E. H.; Keresztes, I.; Collum, D. B. J. Am. Chem. Soc. 2018, 140, 3077 — 3090.
Supporting Information
Structure determination videos featuring Janis’s seducing voice: 1, 2, 3.
146. “Sodium Diisopropylamide in Tetrahydrofuran: Selectivities, Rates, and Mechanisms of Arene Metalations” Algera, R. F.; Ma, Y.; Collum, D. B. J. Am. Chem. Soc. 2017, 139, 15197 — 15204.
145. “Sodium Diisopropylamide in Tetrahydrofuran: Selectivities, Rates, and Mechanisms of Alkene and Diene Isomerizations and Metalations.” Algera, R. F.; Ma, Y.; Collum, D. B. J. Am. Chem. Soc. 2017, 139, 11544 — 11549.
144. “Lithium Hexamethyldisilazide-Mediated Enolization of Highly Substituted Aryl Ketones: Structural and Mechanistic Basis of the E/Z Selectivities.” Mack, K. A.; McClory, A.; Zhang, H.; Gosselin, F.; Collum, D. B. J. Am. Chem. Soc. 2017, 139, 12182 — 12189.
143. “Stereoselective Synthesis of Tetrasubstituted Olefins via Enol Tosylate Formation and Suzuki-Miyaura Coupling.” Li, B. X.; Le, D. N.; Mack, K. A.; McClory, A.; Lim, N.-K.; Cravillion, T.; Savage, S.; Han, C.; Collum, D. B.; Zhang, H.; Gosselin, F. J. Am. Chem. Soc. 2017, 139, 10777 — 10783.
142. “Evans Enolates: Structures and Mechanisms Underlying the Aldol Addition of Oxazolidinone-Derived Boron Enolates.” Zhang, Z.; Collum, D. B. J. Org. Chem. 2017, 82, 7595 — 7601.
141. “Sodium Diisopropylamide: Aggregation, Solvation, and Stability.” Algera, R. F.; Ma, Y.; Collum, D. B. J. Am. Chem. Soc. 2017, 139, 7921 — 7930.
140. “Lithium Diisopropylamide: Non-Equilibrium Kinetics and Lessons Learned about Rate Limitation.” Algera, R. F.; Gupta, L.; Hoepker, A. C.; Liang, J.; Ma, Y.; Singh, K. J.; Collum, D. B. J. Org. Chem. 2017, 82, 4513 — 4532.
139. “Lithium Hexamethyldisilazide Mediated Enolization of Acylated Oxazolidinones: Solvent, Cosolvent, and Isotope Effects on Competing Monomer- and Dimer-Based Pathways.” Reyes-Rodríguez, G. J.; Algera, R. F.; Collum, D. B. J. Am. Chem. Soc. 2017, 139, 1233 — 1244.
138. “Lithium Enolates in the Enantioselective Construction of Tetrasubstituted Carbon Centers with Chiral Lithium Amides as Non-Covalent Stereodirecting Auxiliaries.” Lu, P.; Jackson, J.; Yu, K.; Nguyen, B.; Alvarado, J.; Stivala, C. E.; Ma, Y.; Mack, K. A. Hayton, T.; Collum, D. B.; Zakarian, A. J. Am. Chem. Soc. 2017, 139, 527 — 533.
Supporting Information: 1, 2, 3.
137. “Sodium Diisopropylamide in N,N-Dimethylethylamine: Reactivity, Selectivity, and Synthetic Utility.” Ma, Y.; Algera, R. F.; Collum, D. B. J. Org. Chem. 2016, 81, 11312 — 11315.
136. “Lithium Enolates Derived from Weinreb Amides: Insights into Five-Membered Chelate Rings.” Houghton, M. J.; Collum, D. B. J. Org. Chem. 2016, 81, 11057 — 11064.
135. “Lithium Enolates Derived from Pyroglutaminol: Mechanism and Stereoselectivity of an Azaaldol Addition.” Houghton, M. J.; Huck, C. J.; Wright, S. W.; Collum, D. B. J. Am. Chem. Soc. 2016, 116, 10276 — 10283.
134. “Mixed Aggregates of the Dilithiated Koga Tetraamine: NMR Spectroscopic and Computational Studies.” Ma, Y.; Mack, K. A.; Liang, J.; Keresztes, I.; Collum, D. B.; Zakarian, A. Angew. Chem. Int. Ed. 2016, 55, 10093 — 10097.
133. “Lithium Enolates Derived from Pyroglutaminol: Aggregation, Solvation, and Atropisomerism.” Houghton, M. J.; Biok, N. A.; Huck, C. J.; Algera, R. F.; Keresztes, I.; Wright, S. W.; Collum, D. B. J. Org. Chem.2016, 81, 4149 — 4157.
132. “Structure−Reactivity Relationships in Lithiated Evans Enolates: Influence of Aggregation and Solvation on the Stereochemistry and Mechanism of Aldol Additions.” Tallmadge, E. H.; Jermaks, J.; Collum, D. B. J. Am. Chem. Soc. 2016, 138, 345 — 355.
131. “Solid-State and Solution Structures of Glycinimine-Derived Lithium Enolates.” Jin, K. J.; Collum, D. B. J. Am. Chem. Soc. 2015, 137, 14446 — 14455.
130. “Evans Enolates: Solution Structures of Lithiated Oxazolidinone-Derived Enolates.”
Tallmadge, E. H.; Collum, D. B. J. Am. Chem. Soc. 2015, 137, 13087 — 13095.
129. “Mechanism of Lithium Diisopropylamide-Mediated Ortholithiation of 1,4-bis(Trifluoromethyl)benzene Under Nonequilibrium Conditions: Condition-Dependent Rate Limitation and Lithium Chloride-Catalyzed Inhibition.” Liang, J.; Hoepker, A. C.; Algera, R. F.; Ma, Y.; Collum, D. B. J. Am. Chem. Soc. 2015, 137, 6292 — 6303.
128. “Lithium Diisopropylamide-Mediated Lithiation of 1,4-Difluorobenzene under Nonequilibrium Conditions: Role of Monomer-, Dimer-, and Tetramer-Based Intermediates and Lessons about Rate Limitation.” Liang, J.; Hoepker, A. C.; Bruneau, A. M.; Ma, Y.; Gupta, L.; Collum, D. B. J. Org. Chem. 2014, 79, 11885 — 11902.
127. “Method of Continuous Variation: Characterization of Alkali Metal Enolates Using 1H and 19F NMR Spectroscopies.” Tomasevich, L. L.; Collum, D. B. J. Am. Chem. Soc. 2014, 136, 9710 — 9718.
126. “Preferential Geminal Bis-silylation of 3,4-Benzothiophane Is Caused by the Dominance of Electron Withdrawal by R3Si over Steric Shielding Effects.” Han, Y.; Ma, Y.; Keresztes, I.; Collum, D. B.; Corey, E. J. Org. Lett. 2014, 16, 4678 — 4679.
125. “Solution Structures of Lithium Amino Alkoxides Used in Highly Enantioselective 1,2-Additions.” Bruneau, A. M.; Liou, L.; Collum, D. B. J. Am. Chem. Soc. 2014, 136, 2885 — 2891.
124. “Method of Continuous Variations: Applications of Job Plots to the Study of Molecular Associations in Organometallic Chemistry.” Renny, J. S.; Tomasevich, L. L.; Tallmadge, E. H.; Collum, D. B. Angew. Chem., Int. Ed. 2013, 52, 11998 — 12013.
123. “Structure Determination Using the Method of Continuous Variations: Lithium Phenolates Solvated by Protic and Dipolar Aprotic Ligands.” Tomasevich, L. L.; Collum, D. B. J. Org. Chem. 2013, 78, 7498 — 7507.
122. “Enediolate-Dilithium Amide Mixed Aggregates in the Enantioselective Alkylation of Arylacetic Acids: Structural Studies and a Stereochemical Model.” Ma, Y.; Stivala, C. E.; Wright, A. M.; Hayton, T.; Liang, J.; Keresztes, I.; Lobkovsky, E.; Collum, D. B.; Zakarian, A. J. J. Am. Chem. Soc. 2013, 135, 16853 — 16864.
121. “Lithium Diisopropylamide-Mediated Ortholithiation of 2-Fluropyridines: Rates, Mechanisms, and the Role of Autocatalysis.” Gupta, L.; Hoepker, A. C.; Ma, Y.; Viciu, M. S.; Faggin, M. F.; Collum, D. B. J. Org. Chem. 2013, 78, 4214 — 4230.
120. “Azaaldol Condensation of a Lithium Enolate Solvated by N,N,N’,N’-Tetramethylethylenediamine: Dimer Based 1,2-Addition to Imines.” De Vries, T. S.; Bruneau, A. M.; Liou, L. R.; Subramanian, H.; Collum, D. B. J. Am. Chem. Soc. 2013, 135, 4103 — 4109.
119. “Computational Studies of Lithium Diisopropylamide Deaggregation.” Hoepker, A. C.; Collum, D. B. J. Org. Chem. 2011, 76, 7985 — 7993.
118. “Regioselective Lithium Diisopropylamide-Mediated Ortholithiation of 1-Chloro-3-(trifluoromethyl)benzene: Role of Autocatalysis, Lithium Chloride Catalysis, and Reversibility.” Hoepker, A. C., Gupta, L., Ma, Y., Faggin, M. F., Collum, D. B. J. Am. Chem. Soc. 2011, 133, 7135 — 7151.
117. “Reaction of Lithium Diethylamide with an Alkyl Bromide and Alkyl Benzenesulfonate: Origins of Alkylation, Elimination, and Sulfonation.” Gupta, L., Ramirez, A., Collum, D. B. J. Org. Chem. 2010, 75, 8392 — 8399.
116. “1,4-Addition of Lithium Diisopropylamide to Unsaturated Esters: Role of Rate-Limiting Deaggregation, Autocatalysis, Lithium Chloride Catalysis, and Other Mixed Aggregation Effects.” Ma, Y.; Hoepker, A. C.; Gupta, L.; Faggin, M. F.; Collum, D. B. J. Am. Chem. Soc. 2010, 132, 15610 — 15623.
115. “Experimental Characterization and Computational Study of Unique C,N-Chelated Lithium Dianions.” Gruver, J. M.; West, S. P.; Collum, D. B.; Sarpong, R. J. J. Am. Chem. Soc. 2010, 132, 13212 — 13213.
114. “Mechanism of Lithium Diisopropylamide-Mediated Substitution of 2,6-Difluoropyridine.” Viciu, M. S.; Gupta, L.; Collum, D. B. J. Am. Chem. Soc. 2010, 132, 6361 — 6365.
113. “Lithium Phenolates Solvated by Tetrahydrofuran and 1,2-Dimethoxyethane: Structure Determination Using the Method of Continuous Variation.” De Vries, T. S.; Goswami, A.; Liou, L. R.; Gruver, J. M.; Jayne, E.; Collum, D. B. J. Am. Chem. Soc. 2009, 131, 13142 — 13154.
112. “Lithium Diisopropylamide-Mediated Ortholithiations: Lithium Chloride Catalysis.” Gupta, L.; Hoepker, A. C.; Singh, K. J.; Collum, D. B. J. Org. Chem. 2009, 74, 2231 — 2233.
111. “Structures of β-Amino Ester Enolates: New Strategies Using the Method of Continuous Variation.” Liou, L. R.; McNeil, A. J.; Toombes, G. E. S.; Collum, D. B. J. Am. Chem. Soc. 2008, 130, 17334 — 17341.
110. “Autocatalysis in Lithium Diisopropylamide-Mediated Ortholithiations.” Singh, K. J.; Hoepker, A. C.; Collum, D. B. J. Am. Chem. Soc. 2008, 130, 18008 — 18017.
109. “Anionic Snieckus-Fries Rearrangement: Solvent Effects and Role of Mixed Aggregates.” Riggs, J. C.; Kanwal, S. J.; Ma, Y.; Collum, D. B. J. Am. Chem. Soc. 2008, 130, 13709 — 13717.
108. “Solution Structures of Lithium Enolates, Phenolates, Carboxylates, and Alkoxides in the Presence of N,N,N’,N’-Tetramethylethylenediamine: A Prevalence of Cyclic Dimers.” Gruver, J. M.; Liou, L. R.; McNeil, A. J.; Ramirez, A.; Collum, D. B. J. Org. Chem. 2008, 73, 7743 — 7747.
107. “Synthesis of a 7-Azaindole by Chichibabin Cyclization: Reversible Base-Mediated Dimerization of 3-Picolines.” Ma, Y.; Breslin, S.; Keresztes, I.; Lobkovsky, E.; Collum, D. B. J. Org. Chem. 2008, 73, 9610 — 9618.
106. “Lithium Hexamethyldisilazide-Mediated Enolizations: Influence of Triethylamine on E/Z Selectivities and Enolate Reactivities.” Godenschwager, P. F.; Collum, D. B. J. Am. Chem. Soc. 2008, 130, 8726 — 8732.
105. “Lithium Enolates of Simple Ketones: Structure Determination Using the Method of Continuous Variation.” Liou, R. L.; McNeil, A. J.; Ramirez A.; Toombes, G. E. S.; Gruver, J. M.; Collum, D. B. J. Am. Chem. Soc. 2008, 130, 4859 — 4868.
104. “Structural and Rate Studies of the Formation of Substituted Benzynes.” Riggs, J. C.; Ramirez, A.; Cremeens, M. E.; Bashore, C. G.; Candler, J.; Wirtz, M. C.; Coe, J. W.; Collum, D. B. J. Am. Chem. Soc. 2008, 130, 3406 — 3412.
103. “Lithium Diisopropylamide-Mediated Reactions of Imines, Unsaturated Esters, Epoxides, and Aryl Carbamates: Influence of Hexamethylphosphoramide and Ethereal Cosolvents on Reaction Mechanisms.” Ma, Y.; Collum, D. B. J. Am. Chem. Soc. 2007, 129, 14818 — 14825.
102. “Lithium Hexamethyldisilazide-Mediated Enolizations: Influence of Chelating Ligands and Hydrocarbon Cosolvents on the Rates and Mechanisms.”
Godenschwager, P. F.; Collum, D. B. J. Am. Chem. Soc. 2007, 129, 12023 — 12031.
101. “n-Butyllithium/N,N,N’,N’-Tetramethylethylenediamine-Mediated Ortholithiations of Aryl Oxazolines: Substrate-Dependent Mechanisms.” Chadwick, S. T.; Ramirez, A.; Gupta, L.; Collum, D. B. J. Am. Chem. Soc. 2007, 129, 2259 — 2268.
100. “Lithium Diisopropylamide: solution kinetics and implications for organic synthesis.” McNeil A. J.; Ramirez A.; Collum, D. B. Angew. Chem., Int. Ed. 2007, 46, 3002 — 3017.
99. “Lithium Diisoproplyamide Solvated by Hexamethylphosphoramide: Substrate-Dependent Mechanisms for Dehydrobrominations.”
Ma, Y.; Ramirez, A.; Singh, K. J.; Keresztes, I.; Collum, D. B. J. Am. Chem. Soc. 2006, 128, 15399 — 15404.
98. “Lithium Diisopropylamide-Mediated Ortholithiation and Anionic Fries Rearrangement of Aryl Carbamates: Role of Aggregates and Mixed Aggregates.” Singh, K. J.; Collum, D. B. J. Am. Chem. Soc. 2006, 128, 13753 — 13760.
97. “Mechanism of Acylation of Lithium Phenylacetylide with a Weinreb Amide.” Qu, B.; Collum, D. B. J. Org. Chem. 2006, 71, 7117 — 7119.
96. “Lithium Diisopropylamide-Mediated Enolization: Catalysis by Hemilabile Ligands.” Ramirez, A.; Sun, X.; Collum, D. B. J. Am. Chem. Soc. 2006, 128, 10326 — 10336.
95. “Structure of n-Butyllithium in Mixtures of Ethers and Diamines: Influence of Mixed Solvation on 1,2-Additions to Imines.” Qu, B.; Collum, D. B. J. Am. Chem. Soc. 2006, 128, 9355 — 9360.
94. “Lithiated Imines: Solvent-Dependent Aggregate Structures and Mechanisms of Alkylation.” Qu, B.; Collum, D. B. J. Am. Chem. Soc. 2006, 128, 5939 — 5948.
93. “Addition of n-Butyllithium to an Aldimine: Role of Chelation, Aggregation, and Cooperative Solvation.” Qu, B.; Collum, D. B. J. Am. Chem. Soc. 2005, 127, 10820 — 10821.
92. “Reversible Enolization of β-Amino Carboxamides by Lithium Hexamethyldisilazide.” McNeil, A. J.; Collum, D. B. J. Am. Chem. Soc. 2005, 127, 5655 — 5661.
91. “BF3-Mediated Additions of Organolithiums to Ketimines: X-ray Crystal Structures of BF3-Ketimine Complexes.” Ma, Y.; Lobkovsky, E.; Collum, D. B. J. Org. Chem. 2005, 70, 2335 — 2337.
Supporting Information: 1, 2, 3, 4.
90. “Formation of Benzynes from 2,6-Dihaloaryllithiums: Mechanistic Basis of the Regioselectivity.” Ramirez, A.; Candler, J.; Bashore, C. G.; Wirtz, M. C.; Coe, J. W.; Collum, D. B. J. Am. Chem. Soc. 2004, 126, 14700 — 14701.
89. “Diastereoselective Alkylation of β-Amino Esters: Structural and Rate Studies Reveal Alkylations of Hexameric Lithium Enolates.” McNeil, A. J.; Toombes, G. E. S.; Chandramouli, S. V.; Vanasse, B. J.; Ayers, T. A.; O’Brien, M. K.; Lobkovsky, E.; Gruner, S. M.; Marohn, J. A.; Collum, D. B. J. Am. Chem. Soc. 2004, 126, 16559 — 16568.
88. “Characterization of ß-Amino Ester Enolates as Hexamers via 6Li NMR Spectroscopy.” McNeil, A. J.; Toombes, G. E. S.; Chandramouli, S. V.; Vanasse, B. J.; Ayers, T. A.; O’Brien, M. K.; Lobkovsky, E.; Gruner, S. M.; Marohn, J. A.; Collum, D. B. J. Am. Chem. Soc. 2004, 126, 5938 — 5939.
87. “Lithium Hexamethyldisilazide-Mediated Ketone Enolization: The Influence of Hindered Dialkyl Ethers and Isostructural Dialkylamines on Reaction Rates and Mechanisms.” Zhao, P.; Lucht, B. L.; Kenkre, S. L.; Collum, D. B. J. Org. Chem. 2004, 69, 242 — 249.
86. “Reaction of Ketones with Lithium Hexamethyldisilazide: Competitive Enolizations and 1,2-Additions.” Zhao, P.; Condo, A.; Keresztes, I.; Collum, D. B. J. Am. Chem. Soc. 2004, 126, 3113 — 3118.
85. “Structural and Rate Studies of the 1,2-Additions of Lithium Phenylacetylide to Lithiated Quinazolinones: Influence of Mixed Aggregates on the Reaction Mechanism.” Briggs, T. F.; Winemiller, M. D.; Parsons, Jr., R. L.; Davulcu, A. H.; Harris, G. D.; Fortunak, J. M.; Confalone, P. M. Collum, D. B. J. Am. Chem. Soc. 2004, 126, 5427 — 5435.
84. “Hemilabile Ligands in Organolithium Chemistry: Substituent Effects on Lithium Ion Chelation.” Ramirez, A.; Lobkovsky, E.; Collum, D. B. J. Am. Chem. Soc. 2003, 125, 15376 — 15387.
83. “Ketone Enolization by Lithium Hexamethyldisilazide: Structural and Rate Studies of the Accelerating Effects of Trialkylamines.” Zhao, P.; Collum, D. B. J. Am. Chem. Soc. 2003, 125, 14411 — 14424.
82. “Lithium 2,2,6,6-Tetramethylpiperidide-Mediated α- and β-Lithiations of Epoxides: Solvent-Dependent Mechanisms.” Wiedemann, S. H.; Ramirez, A.; Collum, D. B. J. Am. Chem. Soc. 2003, 125, 15893 — 15901.
81. “Lithium Diisopropylamide-Mediated Lithiations of Imines: Insights into Highly Structure-Dependent Rates and Selectivities.” Liao, S.; and Collum, D. B. J. Am. Chem. Soc. 2003, 125, 15114 — 15127.
Supporting Information: 1, 2, 3, 4.
80. “Lithium Hexamethyldisilazide/Triethylamine-Mediated Ketone Enolization: Remarkable Rate Accelerations Stemming from a Dimer-Based Mechanism.” Zhao, P.; Collum, D. B. J. Am. Chem. Soc. 2003, 125, 4008 — 4009.
79. “Consequences of Correlated Solvation on the Structures and Reactivities of RLi-Diamine Complexes: 1,2-Addition and α-Lithiation Reactions of Imines by TMEDA-Solvated n-Butyllithium and Phenyllithium.” Rutherford J. L.; Hoffmann, D.; Collum, D. B. J. Am. Chem. Soc. 2002, 124, 264 — 271.
78. “Lithium Diisopropylamide: Oligomer Structures at Low Ligand Concentrations.” Rutherford, J. L.; Collum, D. B. J. Am. Chem. Soc. 2001, 123, 199 — 202.
77. “NMR Spectroscopic Investigations of Mixed Aggregates Underlying Highly Enantioselective 1,2-Additions of Lithium Cyclopropylacetylide to Quinazolinones.” Parsons, Jr., R. L.; Fortunak, J. M.; Dorow, R. L.; Harris, G. D.; Kauffman, G. S.; Nugent, W. A.; Winemiller, M. D.; Briggs, T. F.; Xiang, B.; Collum, D. B. J. Am. Chem. Soc. 2001, 123, 9135 — 9143.
76. “Optimizing HMQC for ISn Spin Systems.” Xiang, B.; Winemiller, M. D.; Briggs, T. F.; Fuller, D. J.; Collum, D. B. Magn. Reson. Chem. 2001, 39, 137 — 140.
75. “Solution Structures and Reactivities of the Mixed Aggregates Derived from n-Butyllithium and Vicinal Amino Alkoxides.” Sun, X.; Winemiller, M. D.; Xiang, B.; Collum, D. B. J. Am. Chem. Soc. 2001, 123, 8039 — 8046.
74. “Solution Structures of the Mixed Aggregates Derived from Lithium Acetylides and a Camphor-Derived Amino Alkoxide.” Briggs, T. F.; Winemiller, M. D.; Xiang, B.; Collum, D. B. J. Org. Chem. 2001, 66, 6291 — 6298.
73. “Are n-BuLi/TMEDA-Mediated Arene Ortholithiations Directed? Substituent-Dependent Rates, Substituent-Independent Mechanisms.” Chadwick, S. T.; Rennels, R. A.; Rutherford, J. L.; Collum, D. B. J. Am. Chem. Soc. 2000, 122, 8640 — 8647.
72. “BF3-Mediated Addition of Lithium Phenylacetylide to an Imine: Correlations of Structures and Reactivities. BF3·R3N Derivatives as Substitutes for BF3·Et2O.” Aubrecht, K. B.; Winemiller, M. D.; Collum, D. B. J. Am. Chem. Soc. 2000, 122, 11084 — 11089.
71. “Highly Enantioselective 1,2-Addition of Lithium Acetylide-Ephedrate Complexes: Spectroscopic Evidence for Reaction Proceeding via a 2:2 Tetramer, and X-ray Characterization of Related Complexes.” Xu, F.; Reamer, R. A.; Tillyer, R.; Cummins, J. M.; Grabowski, E. J. J.; Reider, P. J.; Huffman, J. C. ; Collum, D. B. J. Am. Chem. Soc. 2000, 122, 11212 — 11218.
70. “Lithium Diisopropylamide-Mediated Enolizations: Solvent-Dependent Mixed Aggregation Effects.” Sun, X.; Collum, D. B. J. Am. Chem. Soc. 2000, 122, 2459 — 2463.
69. “Lithium Diisopropylamide-Mediated Enolizations: Solvent-Independent Rates, Solvent-Dependent Mechanisms.” Sun, X.; Collum, D. B. J. Am. Chem. Soc. 2000, 122, 2452 — 2458.
68. “Hemilabile Ligands in Organolithium Chemistry: Rate Studies of the LDA-Mediated α- and β-Metalations of Epoxides.” Ramirez, A.; Collum, D. B. J. Am. Chem. Soc. 1999, 121, 11114 — 11121.
67. “Lithium Hexamethyldisilazide: A View of Lithium Ion Solvation Through a Glass-Bottom Boat.” Lucht, B. L.; Collum, D. B. Acc. Chem. Res. 1999, 32, 1035 — 1042.
66. “NMR Spectroscopic Studies of Lithium Diethylamide: Insights into Ring Laddering.” Rutherford, J. L.; Collum, D. B. J. Am. Chem. Soc. 1999, 121, 10198 — 10202.
65. “Solution Structures of Lithium Monoalkylamides (RNHLi).” Aubrecht, K. B.; Lucht, B. L.; Collum, D. B. Organometallics 1999, 18, 2981 — 2987.
64. “Binding of Diamines to n-Butyllithium Dimers: Relative Solvation Energies and Evidence of Correlated Solvation.” Hoffmann, D.; Collum, D. B. J. Am. Chem. Soc. 1998, 120, 5810 — 5811.
63. “Binding of Diamines to n-Butyllithium Dimers: Relative Solvation Energies and Evidence of Correlated Solvation.” Remenar, J. F.; Collum, D. B. J. Am. Chem. Soc. 1998, 120, 4081 — 4086.
62. “Lithium Ephedrate-Mediated Addition of a Lithium Acetylide to a Ketone: Solution Structures and Relative Reactivities of Mixed Aggregates Underlying the High Enantioselectivities.” Thompson, A.; Corley, E. G.; Huntington, M. F.; Grabowski, E. J. J.; Remenar, J. F.; Collum, D. B. J. Am. Chem. Soc.1998, 120, 2028 — 2038.
61. “Ortholithiation of Anisole by n-BuLi-TMEDA: Reaction via Disolvated Dimers.” Rennels, R. A.; Maliakal, A. J.; Collum, D. B. J. Am. Chem. Soc. 1998, 120, 421 — 422.
60. “Lithium 2,2,6,6-Tetramethylpiperidide and Lithium 2,2,4,6,6-Pentamethylpiperidide: Influence of TMEDA and Related Chelating Ligands on the Solution Structures. Characterization of Higher Cyclic Oligomers, Cyclic Dimers, Open Dimers, and Monomers.” Remenar, J. F.; Lucht, B. L.; Kruglyak, D.; Romesberg, F. E.; Gilchirst, J. H.; Collum, D. B. J. Org. Chem. 1997, 62, 5748 — 5754.
59. “Chelation-Based Stabilization of the Transition Structure in a Lithium Diisopropylamide Mediated Dehydrobromination: Avoiding the “Universal Ground State” Assumption.” Remenar, J. F.; Collum, D. B. J. Am. Chem. Soc. 1997, 119, 5573 — 5582.
58. “Lithium Diisopropylamide Solvated by Monodentate and Bidentate Ligands: Solution Structures and Ligand Binding Constants.” Remenar, J. F.; Lucht, B. L.; Collum, D. B. J. Am. Chem. Soc. 1997, 119, 5567 — 5572.
57. “Mechanism of Lithium Diisopropylamide-Mediated Ester Deprotonation: The Role of Disolvated Monomers.” Sun, X.; Kenkre, S. L.; Remenar, J. F.; Gilchrist, J. H.; Collum, D. B. J. Am. Chem. Soc. 1997, 119, 4765 — 4766.
56. “Solution Structure of Lithium Dicyclohexylamide (Cy2NLi) and Related Mixed Aggregates: Comparison with Lithium Diisopropylamide.” Aubrecht, K. B.; Collum, D. B. J. Am. Chem. Soc. 1996, 61, 8674 — 8676.
55. “Polydentate Amine and Ether Solvates of Lithium Hexamethyldisilazide (LiHMDS): Relationship of Ligand Structure, Relative Solvation Energy, and Aggregation State.” Lucht, B. L.; Bernstein, M. P.; Remenar, J. F.; Collum, D. B. J. Am. Chem. Soc. 1996, 118, 10707 — 10718.
54. “Solvation of Lithium Hexamethyldisilazide by N,N-Dimethylethylenediamine: Effects of Chelation on Competitive Solvation and Mixed Aggregation.” Lucht, B. L.; Collum, D. B. J. Am. Chem. Soc. 1996, 118, 3529 — 3530.
53. “Lithium Ion Solvation: Amine and Unsaturated Hydrocarbon Solvates of Lithium Hexamethyldisilazide (LiHMDS).” Lucht, B. L.; Collum, D. B. J. Am. Chem. Soc. 1996, 118, 2217 — 2225.
52. “Ethereal Solvation of Lithium Hexamethyldisilazide: Unexpected Relationships of Solvation Number, Solvation Energy, and Aggregation State.” Lucht, B. L.; Collum, D. B. J. Am. Chem. Soc.1995, 117, 9863 — 9874.
51. “Palladium-Catalyzed Stille Couplings of Aryl-, Vinyl-, and Alkyltrichlorostannanes in Aqueous Solution.” Rai, R.; Aubrecht, K. B.; Collum, D. B. Tetrahedron Lett. 1995, 36, 3111 — 3114.
50. “Mechanism of Lithium Dialkylamide-Mediated Ketone and Imine Deprotonations: An MNDO Study of Monomer and Open Dimer Pathways.”
Romesberg, F. E.; Collum, D. B. J. Am. Chem. Soc. 1995, 117, 2166 — 2178.
49. “Reductions and Radical Cyclizations of Aryl and Alkyl Bromides Mediated by NaBH4 in Aqueous Base.” Rai, R.; Collum, D. B. Tetrahedron Lett. 1994, 35, 6221 — 6224.
48. “6Li/15N NMR-Based Solution Structural Determination of Et2O- and TMEDA-Solvated Lithiophenylacetonitrile and a LiHMDS Mixed Aggregate.” Carlier, P. R.; Lucht, B. L.; Collum, D. B. J. Am. Chem. Soc. 1994, 116, 11602 — 11603.
47. “Lithium Dialkylamide Mixed Aggregation: An NMR Spectroscopic Study of the Influence of Hexamethylphosphoramide (HMPA).” Romesberg, F. E.; Collum, D. B. J. Am. Chem. Soc. 1994, 116, 9198 — 9202.
46. “Lithium Dialkylamide Mixed Aggregation: MNDO Computational Study of Salt and Solvent Dependencies.” Romesberg, F. E.; Collum, D. B. J. Am. Chem. Soc. 1994, 116, 9187 — 9197.
45. “Structure of Lithium 2,2,6,6-Tetramethylpiperidide (LiTMP) and Lithium 2,2,4,4,6,6-Pentamethylpiperidide (LiPMP) in Hydrocarbon Solution: Assignment of Cyclic Trimer and Tetramer Conformational Isomers.” Lucht, B. L.; Collum, D. B. J. Am. Chem. Soc. 1994, 116, 7949 — 7950.
44. “Structure of Lithium Hexamethyldisilazide (LiHMDS): Spectroscopic Study of Ethereal Solvation in the Slow-Exchange Limit.” Lucht, B. L.; Collum, D. B. J. Am. Chem. Soc. 1994, 116, 6009 — 6010.
43. “Lithium Bis(2-adamantyl)amide: Structure and Reactivity of an Extremely Hindered Lithium Dialkylamide.” Sakuma, K.; Gilchrist, J. H.; Romesberg, F. E.; Cajthaml, C. E.; Collum, D. B. Tetrahedron Lett. 1993, 34, 5213 — 5216.
42. “Solvent- and Substrate-Dependent Rates of Imine Metalations by Lithium Diisopropylamide: Understanding the Mechanisms Underlying “krel”.” Bernstein, M. P.; Collum, D. B. J. Am. Chem. Soc. 1993, 115, 8008 — 8018.
41. “Structure of Lithium Hexamethyldisilazide (LiHMDS) in the Presence of Hexamethylphosphoramide (HMPA). Spectroscopic and Computational Studies of Monomers, Dimers, and Triple Ions.” Romesberg, F. E.; Bernstein, M. P.; Gilchrist, J. H.; Harrison, A. T.; Fuller, D. J.; Collum, D. B. J. Am. Chem. Soc.1993, 115, 3475 — 3483.
40. “Metalation of Imines by Lithium Diisopropylamide Solvated by N,N,N’,N’-Tetramethylethylenediamine: Evidence for Solvent-Free Open Dimer Reactive Intermediates.” Bernstein, M. P.; Collum, D. B. J. Am. Chem. Soc. 1993, 115, 789 — 790.
39. “Solution Structures of Lithium Dialkylamides and Related N-Lithiated Species: Results from 6Li-15N Double Labeling Experiments.” Collum, D. B. Acc. Chem. Res. 1993, 26, 227 — 234.
38. “6Li-15N Heteronuclear Multiple Quantum Correlation (HMQC) Spectroscopy: Application to the Structure Determination of Lithium 2,2,6,6-Tetramethylpiperidide Mixed Aggregates.” Gilchrist, J. H.; Harrison, A. T.; Fuller, D. J.; Collum, D. B. Magn. Reson. Chem. 1992, 30, 855 — 859.
37. “Structure and Reactivity of Lithium Diisopropylamide in the Presence of N,N,N’,N’-Tetramethylethylenediamine.” Bernstein, M. P.; Romesberg, F. E.; Fuller, D. J.; Harrison, A. T.; Liu, Q. Y.; Williard, P. G.; Collum, D. B. J. Am. Chem. Soc. 1992, 114, 5100 — 5110.
36. “Determination of Structures of Solvated Lithium Dialkylamides by Semiempirical (MNDO) Methods. Comparison of Theory and Experiment.” Romesberg, F. E.; Collum, D. B. J. Am. Chem. Soc. 1992, 114, 2112 — 2121.
35. “Distinction of Symmetric Lithium Dialkylamide Dimers from Higher Oligomers by Inverse-Detected 15N Homonuclear Zero-Quantum NMR Spectroscopy.” Gilchrist, J. H.; Collum, D. B. J. Am. Chem. Soc. 1992, 114, 794 — 795.
34. “Is N,N,N’,N’-Tetramethylethylenediamine a Good Ligand for Lithium?.” Collum, D. B. Acc. Chem. Res. 1992, 25, 448 — 454.
33. “Mixed Aggregation of Lithium Enolates and Lithium Halides with Lithium 2,2,6,6-Tetramethylpiperidide (LiTMP).” Hall, P. L.; Gilchrist, J. H.; Harrison, A. T.; Fuller, D. J.; Collum, D. B. J. Am. Chem. Soc. 1991, 113, 9575 — 9585.
32. “Effects of Lithium Salts on the Stereoselectivity of Ketone Enolization by Lithium 2,2,6,6-Tetramethylpiperidide (LiTMP). A Convenient Method for Highly E-Selective Enolate Formation.” Hall, P. L.; Gilchrist, J. H.; Collum, D. B. J. Am. Chem. Soc. 1991, 113, 9571 — 9574.
31. “On the Structure of Lithium 2,2,6,6-Tetramethylpiperidide (LiTMP) and Lithium Diisopropylamide (LDA) in the Presence of Hexamethylphosphoramide (HMPA): Structure-Dependent Distribution of Cyclic and Open Dimers, Ion Triplets, and Monomers.” Romesberg, F. E.; Gilchrist, J. H.; Harrison, A. T.; Fuller, D. J.; Collum, D. B. J. Am. Chem. Soc. 1991, 113, 5751 — 5757.
30. “Lithium Diisopropylamide Mixed Aggregates: Structures and Consequences on the Stereochemistry of Ketone Enolate Formation.” Galiano-Roth, A. S.; Kim, Y. J.; Gilchrist, J. H.; Harrison, A. T.; Fuller, D. J.; Collum, D. B. J. Am. Chem. Soc. 1991, 113, 5053 — 5055.
29. “On the Structure and Reactivity of Lithium Diisopropylamide (LDA) in Hydrocarbon Solutions. Formation of Unsolvated Ketone, Ester, and Carboxamide Enolates.” Kim, Y. J.; Bernstein, M. P.; Galiano-Roth, A. S.; Romesberg, F. E.; Williard, P. G.; Fuller, D. J.; Harrison, A. T.; Collum, D. B. J. Org. Chem. 1991, 56, 4435 — 4439.
28. “6Li and 15N Nuclear Magnetic Resonance Spectroscopic Studies of Lithiated Cyclohexanone Phenylamine Revisited. Aggregation-State Determination by Single-Frequency 15N Decoupling.” Gilchrist, J. H.; Harrison, A. T.; Fuller, D. J.; Collum, D. B. J. Am. Chem. Soc. 1990, 112, 4069 — 4070.
27. “Structure and Reactivity of Lithium Diisopropylamide (LDA). The Consequences of Aggregation and Solvation During the Metalation of an N,N-dimethylhydrazone.” Galiano-Roth, A. S.; Collum, D. B. J. Am. Chem. Soc. 1989, 111, 6772 — 6778.
26. “Organometallic Chemistry of Sulfinic Acids. Highly Stereo- and Regioselective Intramolecular Hydroplatinations. X-ray Crystal Structure of (Ph3P)2Pt[trans-SO2CH(CH3)CH2CH(CH2CH3)].” Hallock, J. S.; Galiano-Roth, A. S.; Collum, D. B. Organometallics. 1988, 7, 2486 — 2494.
25. “Structure and Reactivity of Lithium Amides. 6Li, 13C, and 15N NMR Spectroscopic Studies and Colligative Measurements of Lithium Diphenylamide and Lithium Diphenylamide-Lithium Bromide Complex Solvated by Tetrahydrofuran.” DePue, J. S.; Collum, D. B. J. Am. Chem. Soc. 1988, 110, 5518 — 5524.
24. “Structure and Reactivity of Lithium Diphenylamide. Role of Aggregates, Mixed Aggregates, Monomers, and Free Ions on the Rates and Selectivities of N-Alkylation and E2 Elimination.” DePue, J. S.; Collum, D. B. J. Am. Chem. Soc. 1988, 110, 5524 — 5533.
23. “Syntheses and Reactions of η5-(Dimethylboryl)cyclopentadienyl Cobalt and Rhodium Derivatives. Site-Specific Binding of Unsaturated Amines.”
Klang, J. A.; Collum, D. B. Organometallics. 1988, 7, 1532 — 1537.
22. “6Li and 23Na NMR Spectroscopic Studies of Metalated Hydrazone Cryptates. Effects of Ion Triplet Formation on the Stereochemistry of Alkylation.” Galiano-Roth, A. S.; Collum, D. B. J. Am. Chem. Soc. 1988, 110, 3546 — 3553.
21. “6Li, 13C, and 15N NMR Spectroscopic Studies of Lithium Dialkylamides. Solution Structure of Lithium Isopropylcyclohexylamide (LICA) in Tetrahydrofuran.” Galiano-Roth, A. S.; Michaelides, E. M.; Collum, D. B. J. Am. Chem. Soc. 1988, 110, 2658 — 2660.
20. “15N, 13C, and 6Li NMR Spectroscopic Studies and Colligative Measurements of Lithiated Cyclohexanone Phenylimine Solvated by Tetrahydrofuran.” Kallman, N.; Collum, D. B. J. Am. Chem. Soc. 1987, 109, 7446 — 7472.
19. “Solid-State and Solution Studies of Lithiated 2-Carbomethoxycyclohexanone Dimethylhydrazone and Lithiated Cyclohexanone Phenylimine.” Wanat, R. A.; Van Duyne, G.; Clardy, J.; DePue, R. T.; Collum, D. B. J. Am. Chem. Soc. 1986, 108, 3415 — 3422.
18. “Metal- and Alkoxide-Mediated Phosphorus-Oxygen Bond Cleavage in (η5-Cyclopentadienyl) cobalt Phosphinite Ester Complexes.” DePue, R. T.; Klang, J. A.; Collum, D. B. Organometallics. 1986, 5, 1015 — 1018.
17. “Mechanistic Studies of Phosphorus-Oxygen Bond Cleavages in Group 7 Dinuclear Complexes of 2-Pyridyl Dimethylphosphinite.” Klang, J. A.; DePue, R. T.; Collum, D. B. J. Am. Chem. Soc. 1986, 108, 2333 — 2340.
16. “Synthesis of Alternating Hydroxy- and Methyl-Substituted Hydrocarbons by Oxymercuration of Cyclopropylcarbinols.” Still, W. C.; Mohamadi, F.; Collum, D. B. J. Am. Chem. Soc. 1986, 108, 2094 — 2096.
15. “Approaches to the Synthesis and Detection of a Transient Palladium(0) Alkylidene.” Wanat, R. A.; Collum, D. B. Organometallics. 1986, 5, 120 — 127.
14. “Alkoxide-Triggered Ligand Aubstitution. Highly Stereoselective Formation of Unsaturated Phosphinite Ester-Molybdenum Tetracarbonyl Chelates and the X-ray Crystal Structure of (1-Phenylallyl Dimethylphosphinite)molybdenum Tetracarbonyl.” DePue, R. T.; Collum, D. B.; Ziller, J. W.; Churchill, M. R. J. Am. Chem. Soc. 1985, 107, 2131 — 2137.
13. “Improved Synthesis of 4-Vinyl-4′-methyl-2,2′-bipyridine.” Abruna, H. D.; Breikss, A. I.; Collum, D. B. Inorg. Chem. 1985, 24, 987 — 988.
12. “On the Origin of the Stereoselectivity of Hydrazone Alkylations. Investigation of Aggregation Effects and Solution Kinetics.” Wanat, R. A.; Collum, D. B. J. Am. Chem. Soc. 1985, 107, 2078 — 2082.
11. “Substituent Effects on the Stereochemistry of Substituted Cyclohexanone Dimethylhydrazone Alkylations. An X-ray Crystal Structure of Lithiated Cyclohexanone.” Kahne, D.; Gut, S. A.; DePue, R. T.; Mohamadi, F.; Wanat, R. A.; Clardy, J.; Van Duyne, G.; Collum, D. B. J. Am. Chem. Soc. 1984, 106, 4865 — 4869.
10. “Total Synthesis and Stereochemistry of (+)-Phyllanthocindiol.” McGuirk, P. R.; Collum, D. B. J. Org. Chem. 1984, 49, 843 — 852.
9. “Conversion of Ketones to Trisubstituted Olefins under Neutral Conditions.”
Mohamadi, F.; Collum, D. B. Tetrahedron Lett. 1984, 25, 271 — 272.
8. “Mercury(II)-Mediated Opening of Cyclopropanes. Effects of Proximate Internal Nucleophiles on Stereo- and Regioselectivity.” Mohamadi, F.; Hallock, J. S.; Collum, D. B. J. Am. Chem. Soc. 1983, 105, 6882 — 6889.
7. “Total Synthesis of (+)-Phyllanthocin.” McGuirk, P. R.; Collum, D. B. J. Am. Chem. Soc.1982, 104, 4496 — 4497.
6. “Kinetic Cyanations of Ketone Enolates.” Kahne, D.; Collum, D. B. Tetrahedron Lett. 1981, 22, 5011 — 5014.
5. “Synthesis of the Polyether Antibiotic Monensin. 3. Coupling of Precursors and Transformation to Monensin.” McDonald, J. H., III; Still, W. C.; Collum, D. B. J. Am. Chem. Soc. 1980, 102, 2120 — 2121.
4. “Synthesis of the Polyether Antibiotic Monensin. 2. Preparation of Intermediates.” McDonald, J. H., III; Still, W. C.; Collum, D. B. J. Am. Chem. Soc. 1980, 102, 2118 — 2120.
3. “Synthesis of the Polyether Antibiotic Monensin. 1. Strategy and Degradations.” McDonald, J. H., III; Still, W. C.; Collum, D. B. J. Am. Chem. Soc. 1980, 102, 2117 — 2118.
2. “A Highly Stereoselective Synthesis of the C18 Cecropia Juvenile Hormone.” Still, W. C.; McDonald, J. H., III; Mitra, A.; Collum, D. B. Tetrahedron Lett.1979, 20, 593 — 594.
1. “A New Synthesis of Amides and Macrocyclic Lactams.”
Chen, S. C.; Ganem, B.; Collum, D. B. J. Org. Chem.1978, 43, 4393 — 4394.