Enantioselective Addition of Alkynyl Esters and Ethers to Aldehydes Catalyzed by a Cyclopropyl Amino Alcohol Based Zinc Catalyst

A novel and highly enantioselective synthesis of hydroxyalkynyl esters and ethers through the asymmetric addition of alkynyl esters or ethers to aldehydes promoted by a cyclopropyl amino alcohol based zinc catalyst has been developed. The method afforded a library of new enantioenriched hydroxyalkynol esters and ethers (up to 93% yield; 95% ee), and it was compatible with a broad range of functional groups. Moreover, it could be used in the synthesis of carbon-chain-elongated enantioenriched hydroxyalkynol esters and (2R,5R)-musclide-A1, a cardiotonic potentiating principle from musk.