The Michaelreaction of chiralimines 1–3, derived from aromatic ketones’ with substituted electrophilic olefins generated asymmetric tertiary carbon centers. Nevertheless, asymmetric inductions were weaker than those usually observed with cycloalkanone imines.
Reaction of Cyclohexanone Benzylimines with Ethylidenemalonate Diesters. Diphenyl 2-Ethylidenemalonate: A Highly Electrophilic Synthetic Equivalent of Crotonic Esters
Michael alkylation of alpha-substituted and alpha,alpha'-disubstituted cyclohexanone benzylimines with ethylidenemalonate diesters was carried out for mechanistic and synthetic purposes. In the first case, an inverse regioselectivity occurred in comparison with what is generally observed since the Michael adducts resulted from alkylation of the non substituted enamine tautomer. With alpha,alpha'-disubstituted
The condensation of active methylene compounds 1 with acetaldehyde was efficiently promoted by a catalytic amount of lithium bromide in the presence of acetic anhydride to give ethylidene malonates 2 in 77-97% yield.