Chiral Auxiliary Based Reductive Alkylation of α,α‐Diallkyl β‐Phosphonyl Esters

Acyclic alpha,alpha-disubstituted beta-phosphonyl esters containing chiral alcoholic auxiliaries were efficiently prepared and evaluated for the lithium naphthalenide-mediated asymmetric reductive alkylation. Among which, the best diastereoselectivity was received from the substrates bearing a (-)-phenylmenthyl group in leading to alkylated esters with up to 83:17 dr. The diastereoselectivity is proven to be controlled by the pi-facial differentiation created by the chiral ester as well as the geometry of tetrasubstituted enolates generated by the reductive cleavage of C-P bond.