Asymmetric [3,3]-sigmatropic aza-Claisen rearrangement of the (Z)-N-allyl-N,O-silylketene aminal of (3S,4E,αR)-1-benzyloxy-3-(N-propionyl-N-α-methylbenzylamino)hex-4-ene furnishes (2S,3R,4E,αR)-N-α-methylbenzyl-2,3-dimethyl-7-benzyloxyhept-4-enamide in >92% d.e.; rearrangement of the diastereomeric (3R,4E,αR)-(Z)-N,O-silylketene aminal proceeds with low diastereoselectivity.
![Graphical abstract: Double diastereoselective [3,3]-sigmatropic aza-Claisen rearrangements](http://hg.y866.cn/compound/lib/scimg/usr/1/B306323M.jpg)
