1986, Vol.15, No.11

1817-1820

In the presence of a catalytic amount of trityl salts, silyl enol ethers of thioesters stereoselectively react with α,β-unsaturated ketones to afford the Michael adducts in high yields. 5-Oxocarboxylic acid ester derivatives, useful synthetic precursors of various naturally occurring compounds, are stereoselectively obtained by this procedure.