Enantioselective synthesis of butadien-2-ylcarbinols via (silylmethyl)allenic alcohols from chromium-catalyzed additions to aldehydes utilizing chiral carbazole ligands
作者:María Durán-Galván、Shilpa A. Worlikar、Brian T. Connell
DOI:10.1016/j.tet.2010.07.065
日期:2010.9
alcohols are obtained by treatment of aldehydes with (4-bromobut-2-ynyl)trimethylsilane in the presence of a catalytic amount of CrCl3 or CrCl2. Several new tridentate bis(oxazolinyl)carbazole ligands were synthesized and evaluated as the source of chirality. The synthesis of chiral allenic alcohols can be achieved in good yields (58–88%) and enantioselectivities (55–78% ee). Allenic alcohols may be
描述了通过使用中间体(三甲基甲硅烷基)甲基烯丙醇来合成手性,非外消旋丁二烯基羰基醇。通过在催化量的CrCl 3或CrCl 2存在下用(4-溴丁-2-炔基)三甲基硅烷处理醛来获得烯丙醇。合成了几种新的三齿双(恶唑啉基)咔唑配体,并将其评估为手性来源。手性烯丙醇的合成可以实现良好的收率(58-88%)和对映选择性(55-78%ee)。可用TBAF或2 M HCl处理烯丙醇,以43-86%的收率提供所需的二烯。或者,当用N-碘代琥珀酰亚胺处理时,(三甲基甲硅烷基)甲基烯丙醇提供碘丁二烯基甲醇。