Synthesis of oxazino [4,3-a]indoles and pyrano[3,4-b]indoles by cascade addition-cyclization reactions of (1H-indol-2-yl) methanols and vinyl selenones

In recent years vinyl selenones have been identified as valuable and versatile substrates to effect economical and environmentally friendly cascade reactions for the synthesis of various heterocycles compounds [1]. Herein we describe a novel and concise use of MIRC reaction to obtain in one step oxazino[4,3-a]indoles and pyrano[3,4-b]indoles starting from vinyl selenones and (1H-indol-2yl)methanols. These heterocyclic scaffolds are widely present in diverse naturally occurring alkaloids and pharmaceutical or agrochemical products.