A short approach to chaetomellic anhydride A from 2,2-dichloropalmitic acid: elucidation of the mechanism governing the functional rearrangement of the chlorinated pyrrolidin-2-one intermediate
作者:Franco Bellesia、Chiara Danieli、Laurent De Buyck、Roberta Galeazzi、Franco Ghelfi、Adele Mucci、Mario Orena、Ugo M. Pagnoni、Andrew F. Parsons、Fabrizio Roncaglia
DOI:10.1016/j.tet.2005.09.140
日期:2006.1
Chaetomellic anhydride A was efficiently attained in three steps, starting from 2,2-dichloropalmitic acid and 2-(3-chloro-2-propenylamino)pyridine. Atom transfer radical cyclisation selectively formed the cis-stereoisomer of the trichloropyrrolidin-2-one, which underwent a stereospecific functional rearrangement to form a substituted maleimide. The choice of 2-pyridyl, as ‘cyclisation auxiliary’ in
从2,2-二氯棕榈酸和2-(3-氯-2-丙烯基氨基)吡啶开始,从三个步骤中有效地获得了Chaetomellic酸酐A。原子转移自由基环化选择性地形成了三氯吡咯烷-2-酮的顺式-立体异构体,其经历了立体有序的功能重排以形成取代的马来酰亚胺。在原子转移自由基环化步骤中选择2-吡啶基作为“环化助剂”,已证明有利于马来酰亚胺的水解以形成所需的酸酐。