The synthesis of various types of optically active α-(allenylsilane-containing)glycines via a chirality-transferring ester-enolate Claisen rearrangement of α-acyloxy-α-alkynylsilanes is described. The conversion of the rearranged products into the optically active silicon-free α-(allenyl)- and α-substituted-α-(allenyl)glycines was achieved by the removal of the Me2PhSi- or TMS group from the allene
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.