Studies towards the synthesis of indolizin-5(3H)-one derivatives and related 6,5-azabicyclic scaffolds by ring-closing metathesis

Herein, we report on work towards the development of a new strategy for the synthesis of rare and biologically interesting indolizin-5(3H)-ones, which is based around the use of ring-closing metathesis to construct the carbocyclic ring system. This study has provided insights into the general stability of indolizin-5(3H)-ones and their tendency to exist as the tautomeric indolizin-5-ols. Furthermore, this approach has allowed access to other novel structurally related compounds based around unusual 6,5-azabicyclic scaffolds, which are also difficult to generate using typical methods. The azabicyclic compounds synthesized in this study reside in attractive regions of heterocyclic chemical space that are underexploited in current drug and agrochemical discovery efforts. (C) 2014 Elsevier Ltd. All rights reserved