Synthesis of Novel Angular Heterocyclic Lignans by an InCl3-Catalyzed Friedel–Crafts-Type Cyclization

The synthesis of a 1-aryltetralin privileged structure-based library of novel angular heterocyclic lignans is described. Indolotetralins 3, tetrahydroquinolinotetralins 4, and thiochromanotetralins 5 were obtained from the methyl ester of thuriferic acid 2 according to a three-step procedure involving an InCl3-catalyzed Friedel-Crafts-type cyclization as the key step. ((C) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008).