Organocatalytic [2,3] Wittig Rearrangement

Significance

A new organocatalytic [2,3] Wittig rearrangement has been reported. Ketones 1 are treated with 20 mol% of pyrrolidine (2) to provide products of type 3 in good yields and syn diastereoselectivities. The reaction presumably proceeds via an enamine intermediate. Furthermore, the first example of an enantioselective version of this sigmatropic reaction has been developed. Chiral secondary amine 5 mediates the rearrangement of allylic ether 4 to the corresponding product 6 in promising yield, enantioselectivity, and diastereoselectivity.