Synthesis of Enantiopure Primary Amines by Stereoselective Ring Opening of Chiral Octahydro-1,3-benzoxazines by Grignard and Organoaluminum Reagents
作者:Celia Andrés、Javier Nieto、Rafael Pedrosa、Nieves Villamañán
DOI:10.1021/jo960047w
日期:1996.1.1
Chiral 1,3-perhydrobenzoxazines 1, 2, and 9-14, prepared by condensation of 8-(benzylamino)menthol with different aldehydes, react with alkylmagnesium bromides and trimethylaluminum leading to the open amino alcohols 3a-d, 4a-d, and 15-20 in excellent chemical yields and good to excellent diastereomeric excess. The sequential elimination of the menthol appendage by heating with P(2)O(5) and the benzyl
通过将8-(苄基氨基)薄荷醇与不同的醛缩合制得的手性1,3-全氢苯并恶嗪1,2,和9-14与烷基溴化镁和三甲基铝反应,生成开放的氨基醇3a-d,4a-d和15-20出色的化学收率和良好的非对映异构体过量。通过氢解与P(2)O(5)和苄基加热来依次消除薄荷醇,可得到具有优异化学收率和ee的伯胺7a-d,8a-d和27-30。来自格氏试剂的烷基和来自三甲基铝的甲基的加成是从杂环的相反侧开始的,从而产生具有相同立体化学的最终伯胺。