A flexible strategy based on a C2-symmetric pool of chiral substrates: concise synthesis of (+)-valienamine, key intermediate of (+)- pancratistatin, and conduramines A-1 and E.

A new strategy invoking a new application of the [3,3] sigmatropic rearrangement of allylic azides and the presence of a C(2) symmetry element within a pool of chiral substrates was evolved. Not only does this simple flexible strategy provide a concise approach to (+)-valienamine, but it also can readily be adopted for the synthesis of conduramines A-1 and E and the enantiopure azido carbonate 4, a key intermediate of (+)-pancratistatin.