The Collum group studies how aggregation and solvation dictate the reactivity and selectivity of organolithium compounds commonly used by synthetic chemists in both academia and the pharmaceutical industry. A combination of spectroscopic, kinetic, and computational methods bridge organic, organometallic, and analytical chemistry.
The importance of organolithium and organosodium reagents in organic chemistry is indisputable. Reports of the effects of solvents, reaction temperatures, additives, internal coordinating functionalities, electrophile structures, and substituents on product distributions pervade the literature. Nevertheless, complexities resulting from aggregation and solvation render our understanding of the origins of the reactivities and selectivities limited at best. Our group investigates the structural and mechanistic basis of selectivity using a range of spectroscopic, kinetic, and computational methods. A number of projects are in collaboration with pharmaceutical process groups.
- 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.
- 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.
- 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.
- Structures and Reactivities of Sodiated Evans Enolates: Role of Solvation and Mixed Aggregation on the Stereochemistry and Mechanism of Alkylations. Zhang, Z.; Collum, D. B. J. Am. Chem. Soc. 2019, 141, 388.
- 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.