An expeditious and environmentally benign methodology for the synthesis of substituted indoles from cyclic enol ethers and enol lactones

A simple and environmentally friendly method is developed for the synthesis of substituted indoles from commercially available aryl hydrazines and cyclic enol ethers with Montmorillonite-K10 as a heterogeneous catalyst. The catalyst is non-toxic, inexpensive and recyclable and the process is clean, high yielding and operationally simple.