Au-catalyzed cyclization of allenylsilanes. Regioselective conversion to 2-amino-4-silylmethylene γ-butyrolactone

The Au(I)-catalyzed cyclization of an allenylglycine, which possessed a silyl group attached to the opposite side of the allenic terminus, occurred at the allenic center to produce the 2-amino-4-silylmethylene-substituted γ-butyrolactone 2a in a highly regio- and stereoselective manner. The presence of a silyl group at the allenic terminus is crucial for the present 5-endo-dig γ-butyrolactonization.