A Sequential Cyclization Route to Spiroindanyl Heterocycles through Olefin Metathesis and Free Radical Reaction

摘要

Spiroindanylpiperidine and analogs (1) that serve as crucial parts of biologically active compounds,are members of "privileged structure as 1 can be found in ligands for growth hormone secretion,oxytocin,sigma receptor and other G-protein coupled receptor (GPCR)s.As a part of our program to construct various combinatorial libraries for ligands of GPCRs,6 a general synthetic route to 1 and its structural relatives was anticipated to develop for the expansion of the structural diversity of this privileged structure.Though several preparative routes to 1 were reported,structural or positional variation in the construction of spiro-heterocyclic compounds was limited since all the reported synthetic routes to 1 started from 4-substituted piperidines7 or indanone.4 Therefore we envisioned a versatile synthetic route to the spiro-heterocyclic compounds from readily available linear compounds.