Diastereospecific Intramolecular Ullmann Couplings: Unique Chiral Auxiliary for the Preparation of 3,3‘-Disubstituted MeO-BIPHEP Derivatives
作者:E. Gorobets、R. McDonald、B. A. Keay
DOI:10.1021/ol060484p
日期:2006.3.1
auxiliary is described that provides only one diastereomer during intramolecular Ullmann couplings. Treatment of five Ullmann coupling precursors with Cu powder in DMF at 115 degrees C provides 2,2',3,3',6,6'-hexasubstituted 1,1'-biphenyls as single diastereomers in yields ranging from 66% to 91%.
[反应:见正文]描述了一种手性助剂,在分子内Ullmann偶联过程中仅提供一种非对映异构体。在115摄氏度的DMF中用铜粉处理五种Ullmann偶联前体,得到2,2',3,3',6,6'-六取代的1,1'-联苯作为单一非对映异构体,收率范围为66%至91% 。