Enantioselective Transformations and Racemization Studies of Heteroatom Substituted Organolithium Compounds

Although high enantioselectivity distinguishes the generation and reactions of α-amino- and α-alkoxyorganolithium compounds, alkylthio and alkylseleno derivatives (1, X = S, Se) racemize quite readily. The research groups led by R. W. Hoffmann and H. Reich have recently shown that racemization of Li compounds 1 is a unimolecular process and that the rate-determining step involves rotation about the CX bond. These results should form the basis of a strategy for the asymmetric synthesis of sulfides and selenides.