New [4+2]-cycloadditions of generated indolyl enol ethers as heterocyclic donor-activated 1,3-dienes to carbazole derivatives
作者:Ulf Pindur、Ludwig Pfeuffer
DOI:10.1016/s0040-4039(00)96290-7
日期:1987.1
deprotonated by NaH to give generated enol ethers which can be easily trapped by a dienophile such as, e.g., dimethyl acetylenedicarboxylate to form the carbazole derivatives 3, 4, and I. On reaction with the ethoxy-2-methylindolylcarbenium ion 1d under the same conditions, a stereoselective Michael-type addition with formation of 6 takes place.
所述两可烷氧基-吲哚基- methylcarbenium离子1A-1C是通过将NaH去质子化,得到所产生烯醇醚可通过亲双烯体,例如可以容易地捕获作为,例如,乙炔二以形成咔唑衍生物3,4,和一,关于与反应乙氧基-2-甲基吲哚基碳鎓离子1d在相同条件下发生立体选择性迈克尔型加成,形成6。