Enantioselective [2,3]-Wittig rearrangement of allyl picolyl ethers with chiral lithium amides

Abstract

Enantiomerically pure homoallylic alcohols containing pyridine substructure are useful as chiral ligands for asymmetric synthesis and as building blocks for the synthesis of biologically active chiral compounds and natural products. We have successfully performed the highly enantioselective [2,3]-Wittig rearrangement of 2-allyl picolyl ethers using chiral bidentate lithium amides to give 1-(2-pyridyl)-3-butenols with up to 95% ee, and demonstrated that the resulting chiral bidentate diamines, regenerated after the formation of lithioenamines, are excellent chiral ligands for the enantioselective [2,3]-Wittig rearrangement.