Medium-sized cyclophanes. Part 56. 8-Substituted 5-tert-butyl[2.2]metaparacyclophane-1,9-dienes. Preparation, X-ray diffraction study and their treatment with Lewis and protic acids
作者:Takehiko Yamato、Kozo Noda、Hirohisa Tsuzuki
DOI:10.1039/b009932p
日期:——
The preparation of various 8-substituted 5-tert-butyl[2.2]metaparacyclophane-1,9-dienes 1, using the thiacyclophane method, and an X-ray diffraction study of 5-tert-butyl-8-cyano[2.2]metaparacyclophane-1,9-diene 1e are described. Lewis and protic acid-catalyzed reactions of 8-substituted [2.2]metaparacyclophane-1,9-dienes 1b–g in dichloromethane proceeded by isomerization and transannular cyclization
tert-butyl group was observed along with acetylation on the para-benzene ring. The substituent effect on the 8-position was also observed in the present ipso-acetylation. The ipso-acylation at the tert- butyl group of 5-tert-butyl-8-methoxy(2.2)metaparacyclophane (11c) is attributed to the highly activated character of the aryl ring and the increased stabilization of a σ-complex intermediate arising from