The Allyl Cyanate/Isocyanate Rearrangement: An Efficient Tool for the Stereocontrolled Formation of Allylic C-N Bonds

[3,3]-Sigmatropic rearrangements represent powerful methods in the toolbox of synthetic organic chemists for the stereoselective construction of carbon-carbon as well as carbon-heteroatom bonds. Thus, the allyl cyanate/isocyanate rearrangement, although still underused for the preparation of allylamine derivatives, offers clear advantages over other similar methods. It usually occurs at or below ambient temperature with no need to use any metal catalyst, in a stereospecific way, and with a complete transfer of chirality. Moreover, combined with the high reactivity of the resulting isocyanates towards nucleophiles, this rearrangement gives access to various classes of compounds with wide structural and functional diversity. This microreview provides an overview of synthetic applications of this rearrangement since its discovery, with particular emphasis on its utility for the synthesis of complex nitrogen-containing molecules such as natural products.