Regioselective 1,3-Dipolar Cycloaddition Reactions of Unsymmetrical Münchnones (1,3-Oxazolium-5-olates) with 2- and 3-Nitroindoles. A New Synthesis of Pyrrolo[3,4-b]indoles
作者:Gordon W. Gribble、Erin T. Pelkey、Wendy M. Simon、Hernando A. Trujillo
DOI:10.1016/s0040-4020(00)00858-9
日期:2000.12
The unsymmetrical mesoionic münchnones 13 (3-benzyl-2-methyl-4-phenyl-1,3-oxazolium-5-olate) and 14 (3-benzyl-4-methyl-2-phenyl-1,3-oxazolium-5-olate) react with the N-protected 2- and 3-nitroindoles 1 (ethyl 2-nitroindole-1-carboxylate), 6 (3-nitro-1-(phenylsulfonyl)indole), and 17 (ethyl 3-nitroindole-1-carboxylate) in refluxing THF to afford in good to excellent yields the pyrrolo[3,4-b]indoles
不对称介离子münchnones 13(3-苄基-2-甲基-4-苯基-1,3-恶唑鎓-5-醇钠)和14(3-苄基-4-甲基-2-苯基-1,3-恶唑鎓-5- -olate)与N-保护的2-和3-硝基吲哚1(2-硝基吲哚-1-羧酸乙酯),6(3-硝基-1-(苯基磺酰基)吲哚)和17(3-硝基吲哚-1)反应-羧酸盐)在回流的THF中提供良好或优异的收率,得到吡咯并[3,4- b ]吲哚15(2-苄基-1-甲基-3-苯基-4-羰基乙氧基-2,4-二氢吡咯并[3,4 - b ]吲哚),16(2-苄基-3-甲基-1-苯基-4-乙氧羰基-2,4-二氢吡咯并[3,4- b ]吲哚),18(2-苄基-1-甲基-3-苯基-4-(苯磺酰基)-2,4-二氢吡咯并[3,4- b ]吲哚)和19(2-苄基-3-甲基-1-苯基- 4-(苯磺酰基)-2,4-二氢吡咯并[3,4- b ]吲哚)。在某些情况下,与FMO理论所