Transition-metal-free intramolecular double hydrofunctionalization of alkyne to access 6/7/5-fused heterocyclic skeletons

We describe a novel intramolecular double hydrofunctionalization cyclization of alkyne with nitrogen and oxygen nucleophilic groups to construct valuable 6/7/5-fused heterocyclic products. This post-Groebke-Blackburn-Bienayme (GBB) reaction introduces a new class of functionalized isocyanides. Transition-metal-free cyclization, broad substrate scope, and high atom economy were some features of the present protocol. We have disclosed a novel functionalized isonitrile scaffold containing alkyne moiety and designed a new intramolecular double hydrofunctionalization cyclization of alkyne, that affords access to valuable 6/7/5-fused heterocyclic scaffolds.