Rh(II)-catalyzed synthesis of furo[2,3-b]indoles from 3-diazooxindoles and electron-rich arylacetylenes

Abstract

We report a Rh(II)-catalyzed synthesis of fully aromatic furoindoles via cyclopropenation of 3-diazooxindoles with arylacetylenes, followed by in situ rearrangement. A unique aspect of this transformation is the unprecedented activation of the otherwise inert C-2 oxygen atom of the diazooxindole moiety, providing a mild and efficient route from isatins to pharmaceutically relevant furoindole frameworks.