Chiral organometallic reagents, IV. Stereoselective formation of β‐silyloxy‐α‐bromoalkyllithium compounds

Abstract

Abstract The diastereomeric carbenoids 4 have been generated by diastereoselective (84:16) exchange of the diastereotopic bromine atoms in the dibromo compound 3 for lithium at −120°C. The implication of the observed diastereoselectivity for the Nozaki ring‐expansion method is discussed.