Application of Nazarov type electrocyclization to access [6-5-6] and [6-5-5] core embedded new Polycycles: an easy entry to tetrahydrofluorene scaffolds related to Taiwaniaquinoids and C-nor-D homosteroids

Abstract

An easy, efficient and concise approach to tetrahydrofluorene [6, 5, 6] ABC tricyclic core embedded new polycycles have been achieved under relatively mild and catalytic Nazarov type electrocyclization using 2 mol% of Sc(OTf)3 in anhy DCM at rt with high yields. The generality of the reaction has been illustrated by synthesizing diverse polycycles embedded with rare heterotricyclic [6, 5, 5] ABC skeleton.