The analogs of indole phytoalexin cyclobrassinon have been prepared in four steps from corresponding I-substituted 2-chloroindole-3-carboxylic acids, employing a hitherto unknown photochemical cyclization of new indolyl thiocarbamates to 1,3-thiazino[6,5-b]indole-4-one derivatives as a key step. (C) 2001 Elsevier Science Ltd. All rights reserved.