Diastereoselective additions of nucleophiles to alpha-acetoxy ethers using the alpha-(trimethylsilyl)benzyl auxiliary.
We report the diastereoselective addition of a variety of nucleophiles to alpha-(trimethylsilyl)benzyl-substituted oxocarbenium ions. The oxocarbenium ions are generated from alpha-acetoxy ethers, which are easily prepared via reductive acetylation of esters. The alpha-(trimethylsilyl)benzyl auxiliary produces good to excellent facial selectivity with a variety of nucleophiles, including silyl enol ethers, silyl ketene acetals, allylsilanes, and crotylsilanes. The utility of this auxiliary is further demonstrated in a complex ketone aldol coupling reaction. [reaction: see text]
Rychnovsky
Scott D
SD
Department of Chemistry, 516 Rowland Hall, University of California-Irvine, Irvine, CA 92697-2025, USA. srychnov@uci.edu
Cossrow
Jennifer
J