Chiral organolithium species: determination of the rate of cyclization and extent of racemization

Abstract

The rate of intramolecular carbolithiation onto an unactivated alkene to give a six-membered ring has been determined and follows first order kinetics with a half life of ∼90 min at 23 °C; this allows significant racemization using a chiral organolithium species, although good levels of optical purity are obtained with a phenylthio-substituted alkene.