Synthesis of Pyrroles from 1-Dialkylamino-3-phosphoryl(or phosphanyl)allenes through 1,5-Cyclization of Conjugated Azomethine Ylide Intermediates
作者:Martin Reisser、Gerhard Maas
DOI:10.1021/jo049586o
日期:2004.7.1
5-diarylpyrroles 6a−f and [a]-annulated benzo[c]azepines 7a,b,d. These transformations are likely to include conjugated azomethine ylide intermediates that can undergo either a 1,5- or a 1,7-electrocyclization. The periselectivity is markedly shifted toward 1,5-cyclization when the diphenylphosphanyl substituent is replaced by the diphenylphosphoryl group. Thus, 1-dialkylamino-3-(diphenylphosphoryl)allenes
1-二烷基氨基-1,3-二芳基-3- diphenylphosphanylallenes 3A - ë被热转化成一个-annulated 3,5- diarylpyrroles 6A - ˚F和[一个] -annulated苯并[ C ^ ]氮杂7A,b,d。这些转化可能包括可以进行1,5-或1,7-电环化的共轭甲亚胺叶立德中间体。当二苯基膦烷基取代基被二苯基磷酰基取代时,周选择性显着转向1,5-环化。因此,1 -二烷基氨基-3-(二苯基磷酰基)丙二烯4A - ˚F收率吡咯6个,并用改进的产量,除非在丙二烯的3-芳基取代基是富电子太(例如,苯并二氧戊环-5-基,4F → 7F)。可以通过一锅法进行三步或四步氨基丙烯4的制备和热转化,从而提供了从烯胺酮方便地合成[ a ]-环化的3,5-二芳基吡咯的方法。