The research outlined in this proposal focuses on study of a class of 3,3-sigma-tropic rearrangements that can lead to cration of contiguous quaternary centers in a highly stereoselective way. Specifically, examples of the Claisen and aza-Claisen rearrangements, and modifications thereof, in which such centers are generated will be defined as to their kinetics and stereochemical parameters. The studies will encompass both aliphatic acyclic and cyclic substrates. Particular emphasis with the latter is placed on compounds having a vinyl moiety exocyclic to a carbocyclic ring, as such substrates are intended to function as appropriate models for the eventual application of 3,3-sigmatropic rearrangements as part of a novel biomimetic approach to the synthesis of trichothecenes. A search will be undertaken for catalyzed Claisen nd aza-Claisen processes, and the nature of the signatropic rearrangement of quaterinary allyl vinyl ammonium salts is to be defined.
