Starting from (+)-camphor-10-sulfonic acid (1) the chiral crystalline alcohols 3 and 11 were prepared in two steps. Lewis-acid-mediated [4+2]-additions of their acrylates to 1,3-dienes were studied. Notably, the crystalline acrylate 4 underwent TiCl2 (OiPr)2-promoted Diels-Alder addition to cyclopentadiene giving after recrystallization efficiently the pure (2R)-adduct 5.
从(+)-
樟脑-10-
磺酸(1)开始,分两步制备手性结晶醇3和11。研究了
路易斯酸介导的
丙烯酸酯向[1,3-二烯]的[4 + 2]加成反应。值得注意的是,在重结晶后,结晶的
丙烯酸酯4经受了
环戊二烯的TiCl 2(OiPr)2促进的Diels - Alder加成,从而有效地提供了纯的(2 R)加合物5。