Asymmetric conjugate additions of chiral allyl- and crotylphosphonamide anions to .alpha.,.beta.-unsaturated carbonyl compounds: highly stereocontrolled access to vicinally substituted carbon centers and chemically asymmetrized chirons

Reactions of anions derived from chiral nonracemic allyl and crotyl bicyclic phosphonamides with α,β-unsaturated cyclic ketones, esters, lactones, and lactams take place at the γ-position of the reagents and lead to diastereomerically pure or highly enriched products of conjugate addition. The option to quench the corresponding enolates with various alkyl halides offers a versatile approach to vicinal substitution including the generation of quaternary carbon centers