ORGN 93

The presence of the lactam carbonyl in templates such as (1) would allow for possible further functionalisation en route to the natural product targets. Recent approaches to the construction of this heterocyclic system by other groups have included the diastereoselective vinylogous Mannich reaction, Bischler-Napieralski reaction, Fischer indole synthesis and the asymmetric Pictet-Spengler reaction. We have developed a new and general approach for the stereoselective synthesis of a wide range of nonracemic heterocycles. Our protocol involves the cyclisation of pendent aromatic substituents onto N-acyliminium intermediates as a key ring-forming step.