Regiospecific <i>C</i>-Acylation of Pyrroles and Indoles Using <i>N</i>-Acylbenzotriazoles
作者:Alan R. Katritzky、Kazuyuki Suzuki、Sandeep K. Singh、Hai-Ying He
DOI:10.1021/jo034187z
日期:2003.7.1
Reactions of pyrrole (2) or 1-methylpyrrole (4) with readily available N-acylbenzotriazoles 1a-g (RCOBt, where R = 4-tolyl, 4-nitrophenyl, 4-diethylaminophenyl, 2-furyl, 2-pyridyl, 2-indolyl, or 2-pyrrolyl) in the presence of TiCl(4) produced 2-acylpyrroles 3a-g and 5a-g in good to excellent yields. 1-Triisopropylsilylpyrrole (6) under the same conditions gave the respective 3-acylpyrroles 7a-g. Similarly
吡咯(2)或1-甲基吡咯(4)与易于获得的N-酰基苯并三唑1a-g(RCOBt,其中R = 4-甲苯基,4-硝基苯基,4-二乙基氨基苯基,2-呋喃基,2-吡啶基,2- TiCl(4)存在下,吲哚基或2-吡咯基)可以很好地产生2-酰基吡咯3a-g和5a-g。在相同条件下的1-三异丙基甲硅烷基吡咯(6)得到各自的3-酰基吡咯7a-g。类似地,吲哚(9)和1-甲基吲哚(11)给出相应的3-酰化衍生物10a-g和12a-g。这些结果表明,当相应的酰氯不易获得时,N-酰基苯并三唑类化合物如1c,f,g是温和的,区域选择性的和区域特异性的C-酰化剂,特别有用。