Water-Accelerated Organometallic Chemistry: Alkyne Carboalumination – Sulfinimine Addition and Asymmetric Synthesis of Allylic Amines

Carboalumination of alkynes in the presence of catalytic Cp2ZrCl2 and H2O affords vinyl-alane intermediates, which serve as nucleophiles in the subsequent addition to enantiomerically enriched (tert-butyl)- and (para-tolyl)sulfinimines. This new in situ protocol produces two new CC bonds. Chiral allylic sulfinamides are obtained in high diastereoselectivity and in good yield. Cleavage of the chiral auxiliary leads to synthetically useful allylic amine building blocks, and facile oxidative degradation of the alkene moiety can be used as an approach toward amino acid derivatives and for assignment of absolute configuration.