Concise Synthesis of the Bicyclic Scaffold of N-Methylwelwitindolinone C Isothiocyanate via an Indolyne Cyclization

A concise synthesis of the N-methylwelwitindolinone C isothiocyanate scaffold is disclosed. The approach relies on an indolyne cyclization to construct the [4.3.1]-bicyclic ring system present in the natural product. Subsequent oxidation of the indole core occurs with excellent diastereoselectivity to afford oxindole 2, the structure of which was confirmed by X-ray crystallographic analysis.