Asymmetric Addition of Oragnozinc Reagentsto Nitrones Enantiomeric Enhancement by A RacemicProduct-like Additive

摘要

@@1.Introduction The development of efficient carbon-carbon bond formation by asymmetric nucleophilic addition to carbon-nitrogen double bond is quite important.Among the imine compounds,nitrone might be a promising candidate as the substrate because it possesses an electronegative oxygen,which can not only activate the carbon-nitrogen double bond but also coordinate to metals. The asymmetric addition of acetylide to nitrones is a useful method for the production of chiral propargylamines,which are versatile building blocks for preparation of the optically active nitrogen containing compounds and can also encounter as part of biologically active compounds.Although several diastereoselective methods for nucleophilic addition of zinc acetylides to nitrones were recently reported, the enatioselective methods were limited and are still regarded as one of the challenging problems especially in terms of availability of chiral auxiliaries.