Chiral Dipole-Stabilized Anions: Experiment and Theory in Nonbenzylic Systems. 100percent Stereoselective Deprotonation and Two-Electron vs Single-Electron Transfer in the Chemistry of Lithium and Copper Piperidinooxazolines

Article abstract of DOI:10.1021/jo00262a039

A chiral oxazoline derived from valine mediates the 100percent stereoselective deprotonation of the 2-position of piperidine, forming a single diastereomer organolithium, which is dipole-stabilized.The organolithium species undergoes either two electron or single electron transfer processes, but the latter predominate for most electrophiles.The corresponding cuprates undergo only single electron transfer processes.MNDO calculations indicate little difference in energy between most of the conformational and stereoisomers of the organolithium, suggesting that the single organolithium diastereomer is formed under kinetic control.Mechanistic rationales for the unprecedented deprotonation, as well as the single electron transfer processes, are presented.