Factors controlling the regioselectivity of the addition of dimethyl phosphite to dibenzylidene derivatives of ketones

Abstract

1. Dibenzylidene derivatives of acetone, cyclohexanone, and cyclopentanone react with dimethyl phosphite in the presence of sodium methoxide by the 1,4-addition scheme, with the formation of mono- and bis- adducts with a γ-ketophosphonate structure. 2. In contrast to the benzylidene derivatives of acetone, cyclohexanone,and cyclopentanone, because of steric hindrance by the phosphono-substituted benzyl group, the monoadducts do not form addition products with dimethyl phosphite at the carbonyl group. © 1980 Plenum Publishing Corporation.