A new class of chiral spirocyclic borate ligands 5a–d with a rigid borocycle has been developed. The catalyst formed from chromium(II)-5a promotes the highly efficient enantioselective Nozaki–Hiyama allylation of alkyl and aryl ketones using allyl bromide. The scope of the present method is shown to be wide, and it affords an efficient access to chiral tertiary homoallylic alcohols.
of α‐methylene‐γ‐lactones through the palladium(II)‐catalyzed lactonization of homoallylic alcohols with alkynamides has been reported. The hydroxyl group in the terminal olefins cooperates with the amide in alkynamides to promote the cyclization by suppressing the β‐H elimination. This process provides a route to construct naturally occurring biologically multifunctional α‐methylene‐γ‐lactones.