Au-catalyzed cyclization of allenylsilanes. Regioselective conversion to 2-amino-4-silylmethylene γ-butyrolactone
摘要:
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 gamma-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 gamma-butyrolactonization. (C) 2011 Elsevier Ltd. All rights reserved.
Au(I)-catalyzed efficient synthesis of α-acyloxy-α′-silyl ketones from α-acyloxy-α-alkynylsilanes
摘要:
The Au(I)-catalyzed novel conversion of alpha-acyloxy-alpha-alkynylsilanes to alpha-acyloxy-alpha '-silyl ketones is reported. Ph3PAuOTf in dioxane in the presence of 1 equiv of H2O efficiently catalyzed both the [3,3] sigmatropic rearrangement and allenic transformation of the resulting ester to give the alpha-acyloxy-alpha '-silyl ketones in a one-pot procedure. (C) 2007 Elsevier Ltd. All rights reserved.