Regio- and enantioselective synthesis of allenic esters by samarium(II)-mediated reduction of propargylic compounds through dynamic kinetic protonation

Regioselective synthesis of allenic esters was attained by SmI2-mediated reduction of propargylic phosphates and ethers bearing alkoxycarbonyl groups at the acetylene terminus. Using suitable chiral proton source in this system, highly enantio-enriched allenic ester was obtained through dynamic kinetic resolution by Lewis acidic Sm(III)-mediated enantioselective protonation, even if starting with racemic propargylic phosphates.