Synthesis of the syn and anti isomer of 1,4,5,8,9,12-hexahydro-2,3,6,7,10,11-hexamethylidene-1,4:5,8:9,12-trimethano triphenylene and Diels–Alder reactivity of the syn isomer

The title compounds, new members in the class of tris-annelated benzenes with [2.2.1] bicyclic rings, were obtained in high yields by coupling of 2-bromo-3-trimethyltin-5,6-dimethylenenorborn-2-ene with copper(I) 2-thiophenecarboxylate (CuTC). The syn isomer was reacted with 3 equiv. of the dienophiles TCNE, DMAD, PTAD and norbornadiene to afford the corresponding cycloadducts.