Asymmetric synthesis of cyclic ethers by rearrangement of oxonium ylides generated from chiral copper carbenoids

Article abstract of DOI:10.1016/S0040-4039(97)10441-5

Tetrahydrofuran-3-ones and tetrahydropyran-3-ones can be prepared enantioselectively by rearrangement of the ylide-type intermediates generated by the reaction of a chiral copper carbenoid with the oxygen atom of a pendant allylic ether. Cyclic ethers with enantiomeric excesses of up to 57% have been obtained using a copper complex of the enantiomerically pure diimine 1a for carbenoid generation.