Catalytic Asymmetric Propargylation

Developments of catalytic propargylation reactions are presented. Optically active α-oxazolidinonylallenylstannane, prepared from N-propargyloxazolidinone via a lithiation/stannylation sequence, is an efficient reagent for the asymmetric propargylation of carbonyl compounds. Lai and Soderquist successfully extended the use of chiral organoborane regents containing the 10-trimethylsilyl-9-borabicyclo[3.3.2]-decane (10-TMS-9-BBD) ring system. Denmark and Wynn demonstrated that a weak achiral Lewis acid such as SiCl4 can be activated by a chiral Lewis base to afford a strong chiral Lewis acid. Cozzi, Umani-Ronchi, and co-workers developed the first catalytic enantioselective addition of allylic chloride to aldehydes using the chiral complex [Cr(Salen)] as the catalyst. A transition metal-catalyzed asymmetric version of Friedel-Crafts-type propargylation has been developed by using chiral thiolate-bridge diruthenium complexes.