3,6-Dimethoxyanthranilic acid (2) has been prepared by a procedure that is more reliable than our earlier one and used as a 3,6-dimerhoxybenzyne precursor in a reaction with anisole to give 1,4-dihydro-1,5,8-trimethoxy-1,4-ethenonaphthalenelene (1,5,8-trimethoxybenzobarrelene) (1). Trifluoroacetic acid-catalysed rearrangement of this benzobarrelene (1) gave as precedented products of bicyclo-rearrangement 3,4-dihydro-5,8-dimethoxy-1,4-erhenonaphthalen-2(1H)-one (5,8-dimethoxybenzobarrelenone) (3) and 5,9-dihydro-1,4-dimethoxy-5 9-methanobenzocyclohepten-6-one (7) along with 2,4',5-trimethoxybiphenyl (6), the product of a remarkable retro-Friedel-Crafts protodealkoxyalkylative fragmentation of the bicyclic system. Similar reactions were observed with perchloric acid. The structure of this unexpected biphenyl was confirmed by its preparation by Gomberg-Bachman-Hey arylation of 1,4-dimethoxybenzene.
3,6-Dimethoxyanthranilic acid (2) has been prepared by a procedure that is more reliable than our earlier one and used as a 3,6-dimerhoxybenzyne precursor in a reaction with anisole to give 1,4-dihydro-1,5,8-trimethoxy-1,4-ethenonaphthalenelene (1,5,8-trimethoxybenzobarrelene) (1). Trifluoroacetic acid-catalysed rearrangement of this benzobarrelene (1) gave as precedented products of bicyclo-rearrangement 3,4-dihydro-5,8-dimethoxy-1,4-erhenonaphthalen-2(1H)-one (5,8-dimethoxybenzobarrelenone) (3) and 5,9-dihydro-1,4-dimethoxy-5 9-methanobenzocyclohepten-6-one (7) along with 2,4',5-trimethoxybiphenyl (6), the product of a remarkable retro-Friedel-Crafts protodealkoxyalkylative fragmentation of the bicyclic system. Similar reactions were observed with perchloric acid. The structure of this unexpected biphenyl was confirmed by its preparation by Gomberg-Bachman-Hey arylation of 1,4-dimethoxybenzene.
Rearrangement reactions of bicyclic systems. Part V. 1 Acid-catalysed rearrangements of 1,4-dihydro-1,5,8-trimethoxy-1,4-ethenonaphthalene and the remarkable effect of aromatic methoxy-groups on the course of the reaction
作者:Neil J. Hales、Harry Heaney、John H. Hollinshead、Ram P. Sharma
DOI:10.1016/0040-4020(95)00354-b
日期:1995.7
3,6-Dimethoxyanthranilic acid (2) has been prepared by a procedure that is more reliable than our earlier one and used as a 3,6-dimerhoxybenzyne precursor in a reaction with anisole to give 1,4-dihydro-1,5,8-trimethoxy-1,4-ethenonaphthalenelene (1,5,8-trimethoxybenzobarrelene) (1). Trifluoroacetic acid-catalysed rearrangement of this benzobarrelene (1) gave as precedented products of bicyclo-rearrangement 3,4-dihydro-5,8-dimethoxy-1,4-erhenonaphthalen-2(1H)-one (5,8-dimethoxybenzobarrelenone) (3) and 5,9-dihydro-1,4-dimethoxy-5 9-methanobenzocyclohepten-6-one (7) along with 2,4',5-trimethoxybiphenyl (6), the product of a remarkable retro-Friedel-Crafts protodealkoxyalkylative fragmentation of the bicyclic system. Similar reactions were observed with perchloric acid. The structure of this unexpected biphenyl was confirmed by its preparation by Gomberg-Bachman-Hey arylation of 1,4-dimethoxybenzene.