[2,3]-Sigmatropic rearrangement of ynamides: preparation of α-amino allenephosphonates

J Org Chem. 2012 Jun 15;77(12):5439-44. doi: 10.1021/jo300790m. Epub 2012 May 30.

Abstract

α-Amino allenephosphonates were easily prepared in two steps from protected amines, propargyl alcohols, and chlorophosphites. First, ynamides were synthesized from unprotected 1-bromopropargyl alcohols using a copper(II) catalyzed coupling reaction. In the second step, the previously prepared ynamides were transformed directly to allenes through a [2,3]-sigmatropic rearrangement of propargyl phosphites. This efficient method led to the formation of a series of α-amino allenephosphonates with diverse substituents on the amine, the phosphonate, and the allene moieties.