Tandem ‘inverse electron-demand’ Diels-Alder reactions of dienamines with a 1,2,4,5-tetrazine. A new azo-bridged ring system
摘要:
Reaction of (EE)-1-morpholino-2-methylpenta-1,3-diene la with dimethyl 1,2,4,5-tetrazine-3,6-di-carboxylate 2 in acetonitrile solution gives dimethyl 2,5-dimethyl-3-morpholino-8,9-diazatricyclo[2.2.2.0(2,6)]oct-8-ene-1,4-dicarboxylate 4a, in high yield (79%) and with high apparent diastereoselectivity; the 1-(4-methylpiperazino) analogue Ib similarly gives compound 4b (66%). Compounds 4a and 4b are the first recorded representatives of this bridged tricyclic ring system. In contrast 2-methyl-1-morpholinocyclopentadiene 5 reacts with 2 mol. equiv. of the tetrazine 2, giving the cyclopentadipyridazine 6. (C) 1998 Elsevier Science Ltd. All rights reserved.
Tandem ‘inverse electron-demand’ Diels-Alder reactions of dienamines with a 1,2,4,5-tetrazine. A new azo-bridged ring system
作者:András Kotschy、David M. Smith、Attila Cs. Bényei
DOI:10.1016/s0040-4039(97)10699-2
日期:1998.2
Reaction of (EE)-1-morpholino-2-methylpenta-1,3-diene la with dimethyl 1,2,4,5-tetrazine-3,6-di-carboxylate 2 in acetonitrile solution gives dimethyl 2,5-dimethyl-3-morpholino-8,9-diazatricyclo[2.2.2.0(2,6)]oct-8-ene-1,4-dicarboxylate 4a, in high yield (79%) and with high apparent diastereoselectivity; the 1-(4-methylpiperazino) analogue Ib similarly gives compound 4b (66%). Compounds 4a and 4b are the first recorded representatives of this bridged tricyclic ring system. In contrast 2-methyl-1-morpholinocyclopentadiene 5 reacts with 2 mol. equiv. of the tetrazine 2, giving the cyclopentadipyridazine 6. (C) 1998 Elsevier Science Ltd. All rights reserved.