A new synthesis of a,@-unsaturated sulfoxides which involves the reaction of carbonyl compounds with 1-diethylphosphoryl-1-methylsulfinylmethyllithium (4) is described. The reaction was found to be nonstereoselective, mixtures of E and 2 isomers being formed from aldehydes and unsymmetrical ketones. The geometry of mono-and disubstituted vinyl sulfoxides so formed was assigned with the aid of NMR spectroscopic methods (INDOR, ...
