Abstract: The aim of this study was to examine the styrene group as a cyclization terminator of a biomimetic polyene cyclization, in the hope that it would participate so as to favor formation of a five-membered ring as suggested by the conversion of cation G into H. The model substrate 1 was synthesized from the bromodiene 6 (prepared according to Scheme I) by the sequence outlincd in Scheme 11. On treatment with stannic chloride in ...