Concise stereoselective synthesis of 1-perfluoroalkyl enamines via the addition of N-lithiated amines to enol ethers and their subsequent metalation to form new functionalized enamines

Abstract

Addition of lithium amides derived from a range of cyclic, sterically demanding, and chiral amines, to trifluoromethyl (Z)-enol ethers 1 and 4, provides stereoselectively the corresponding (Z)-enamines 3a–e and 7 in good yields. This reaction has been extended to the perfluoroalkyl and chlorofluoroalkyl enol ethers (CF₂Cl, C₂F₅). The enamines can react with Bu^tLi to give vinylic anions and, after quenching with aldehydes and ethyl chloroformate, provide new functionalized enamines 12–16.