Sequential Diels−Alder Reaction of in Situ Generated 2,3-Dimethylenepyrrole and Carbodienophiles: Rapid Synthesis of 2,3,6,7-Tetrasubstituted Carbazoles
作者:Jeffrey T. Vessels、Slawomir Z. Janicki、Peter A. Petillo
DOI:10.1021/ol991220o
日期:2000.1.1
[reaction: see text] 2,3,6,7-Tetrasubstituted-1,2,3,4,5,6,7,8-octahydrocarbazoles 2 were synthesized in 46-90% yields by sequential Diels-Alder reactions from N-benzyl-2,5-dimethyl-3,4-bisacetoxymethylpyrrole (1) and dienophiles such as maleic anhydride, maleimides, ethyl maleate, fumaronitrile, and ethyl acrylate. The 2,3,6,7-tetrasubstituted carbazoles 3 were then synthesized in 32-87% yields from
[反应:参见正文]通过N的连续Diels-Alder反应,以46-90%的产率合成了2,3,6,7-四取代-1,2,3,4,5,6,7,8-八氢咔唑2 -苄基-2,5-二甲基-3,4-双乙酰氧基甲基吡咯(1)和亲二烯体,例如马来酸酐,马来酰亚胺,马来酸乙酯,富马腈和丙烯酸乙酯。然后通过用DDQ氧化从2合成3,2,6,7-四取代的咔唑3,产率为32-87%。