Asymmetric conjugate additions of chiral phosphonamide anions to alpha,beta-unsaturated carbonyl compounds. A versatile method for vicinally substituted chirons
Reactions of anions derived from chiral nonracemic allyl, crotyl, and cinnamyl bicyclic C(2)-symmetrical phosphonamides with alpha, beta-unsaturated cyclic ketones, esters, lactones, and lactams take place at the gamma-position of the reagents. The products are diastereomerically pure or enriched beta-substituted carbonyl compounds. The method also provides easy access to vicinal substitution of as many as three stereogenic centers including in some cases quaternary carbon atoms, in a one-pot sequence.
Hanessian
S
Department of Chemistry, Universite de Montreal, C.P. 6128, Succursale Centreville, Montreal, Quebec H3C 3J7, Canada.
Gomtsyan
A
Malek
N