Phosphonamide stabilized allylic carbanions. New homoenolate anion equivalents

The chemistry of phosphonamide stabilized allylic carbanions derived from the 1,2-addition of tervalent phosphorus siloxanes with a,b-unsaturated aldehydes has been studied. An i n situ synthesis of allylic cu-silyloxyphosphonamides, followed by metalation and regioselective y-alkylation of the allylic carbanion, yields a versatile “active ester”. Transesterification under mild conditions gives esters and lactones and defines a new homoenolate equivalency.