A three-step synthesis of stable and storable α-benzenesulfinyl
enol ethers from lactones entails (a) conversion of a lactone to
an enol triflate or phosphate; (b) Ni(0) and Pd(0) cross-coupling of
the enol triflate or phosphate with a sodium arenethiolate to give an α-arenethio
enol ether; and (c) oxidation of an arenethio group to a sulfoxide.
The α-benzenesulfinyl enol ethers undergo sulfoxide-lithium
exchange on reaction with n-BuLi to give α-lithiated
enol ethers thus making the α-benzenesulfinyl group a surrogate
for the trialkylstannyl group which has hitherto served as the most
common precursor to α-lithiated enol ethers.
coupling - nickel - palladium - catalysis - sulfoxides - enol ether