A Facile Synthesis of Chiral 4-(tert-Butylsulfinylamino)-2-oxophosphonates and Their Conversion into 5,5-Disubstituted 2-Benzylidene-3-oxopyrrolidines

The addition of the dianion derived from 2-oxophosphonates to chiral N-( TERT-butylsulfinyl)ketimines or -aldimine under mild reaction conditions afforded 4-( TERT-butylsulfinylamino)-2-oxoalkylphosphonates with good to excellent diastereoselectivity. The latter was then converted into an enantiopure 5,5-disubstituted 2-(dimethoxyphosphoryl)pyrrolidin-3-one via an intramolecular N-H insertion. Subsequent Horner-Wadsworth-Emmons reaction gave the corresponding 2-benzylidene derivatives.