Nucleophilic Addition of Ethyl 3-Bromodifluoromethyl-3-benzyloxyacrylate to Imines: An Effective Entry to Novel gemDifluorinated Amino Esters and their Derivatives

Zinc- or tetrakis(dimethylamino)ethylene (TDAE)-mediated nucleophilic addition of ethyl 3-bromodifluoromethyl-3benzyloxyacrylate to imines afforded gem-difluorovinyl substituted (beta)-amino esters ((alpha)-addition product) and gemdifluorinated (delta)-amino esters ((gamma)-addition product) or their cyclized derivatives, depending on the mediator and the nature of substituents on the imines.