Diversity-oriented synthesis of indole-fused scaffolds and bis(indolyl)methane from tosyl-protected tryptamine.

An efficient, diversity-oriented synthesis of indole-1,2-fused 1,4-benzodiazepines, tetrahydro-β-carbolines, and 2,2'-bis(indolyl)methanes was established starting from tosyl-protected tryptamine. These diverse privileged skeletons were controllably constructed by adjusting different hydride donors and Brønsted acids. A variety of indole-1,2-fused 1,4-benzodiazepines were facilely accessed using benzaldehydes bearing cyclic amines as hydride donors a cascade -alkylation/dehydration/[1,5]-hydride transfer/Friedel-Crafts alkylation sequence.

Chemoselective and diastereoselective construction of 4-alkylidene-tetrahydroquinoline a redox-neutral vinylogous cascade [1,7]-hydride transfer/6- cyclization strategy.

Herein, we disclose a chemoselective and diastereoselective synthesis of the medicinally significant 4-alkylidene-tetrahydroquinoline a redox-neutral vinylogous cascade condensation/[1,7]-hydride transfer/6- cyclization strategy, which features a novel product skeleton, high chemoselectivity and diastereoselectivity, facile introduction of 4-alkylidenyl motifs, employment of α,β,γ,δ-unsaturated dicyanoalkenes as novel hydride acceptors, and green and metal-free conditions with water as the only by-product. Additionally, the versatility of α,α-dicyanoalkenes has been fully exploited as hydride acceptors and γ-exclusive nucleophiles consecutively for accessing novel heterocyclic skeletons.