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