Functionalized thiazoloindole-3-thiones and their spirocongeners from 2-acylethynyl-4,5,6,7-tetrahydroindoles with carbon disulfide

Accessible 2-acylethynyl-4,5,6,7-tetrahydroindoles undergo stereoselective base-catalyzed (NaOH/DMSO, room temperature) [3+2]-cyclization with carbon disulfide to deliver 5,6,7,8-tetrahydro-1H,3H-thiazolo[3,4-a]indole-3-thiones incorporating Z-α,β-ethylenic ketones in up to 76% yield. The synthesized compounds are quantitatively aromatized to...