piperidines and lentiginosine

We describe a tandem Mitsunobu/3,3-sigmatropic rearrangement of allylic azides on a chiral auxiliary system that favors one regioisomer thanks to its exceptional steric bias. The sequence may be completed by the oxidative cleavage of the auxiliary or by a ring-closing metathesis reaction that produces a carbo- or heterocycle directly and a recyclable form of the chiral auxiliary. Applications of the methodology to the total synthesis of (+)-coniine, (+)-lentiginosin, and (+)-pumiliotoxin C are reported.

Topics: Alkaloids; Allyl Compounds; Amino Acids; Animals; Azides; Heterocyclic Compounds; Piperidines; Quinolines; Stereoisomerism