Stereoselective [2,3]-sigmatropic rearrangements of unstabilized nitrogen Ylides

by Gawley, R. E.; Moon, K.

[GRAPHICS] The steric course of the [2,3]-rearrangement of several unstabilized nitrogen ylides has been investigated. The reactions proceed cleanly through an anti transition state, affording modest to good yields of a single diastereomer of the product. In two examples containing an N-cinnamyl group, a competing [1,2]-rearrangement affords a minor product.