Enantio- and Diastereoselectivity in 1,3-Dipolar Cycloaddition Reactions of Nitrones with 3-Crotonoyl-2-oxazolidinone Catalyzed by Ni(II)- Binaphthyldiimine Complexes
作者:Hiroyuki Suga、Akikazu Kakehi、Suketaka Ito、Hiroaki Sugimoto
DOI:10.1246/bcsj.76.327
日期:2003.2
Chiral Ni(II)-1,1′-binaphthyl-2,2′-diimine complexes were found to be effective Lewis-acid catalysts for an asymmetric 1,3-dipolar cycloaddition reaction of N-benzylideneaniline N-oxide with 3-crotonoyl-2-oxazolidinone. In the presence of molecular sieves (4 A), when the chiral N,N′-bis(2,6-dichlorobenzylidene)-1,1′-binaphthyl-2,2′-diamine (BINIM-DC) and Ni(ClO4)2·6H2O were used to prepare the catalyst
发现手性 Ni(II)-1,1'-联萘-2,2'-二亚胺配合物是有效的路易斯酸催化剂,用于 N-亚苄基苯胺 N-氧化物与 3-巴豆酰的不对称 1,3-偶极环加成反应-2-恶唑烷酮。在分子筛 (4 A) 存在下,当手性 N,N'-双(2,6-二氯亚苄基)-1,1'-联萘-2,2'-二胺 (BINIM-DC) 和 Ni(ClO4 )2·6H2O 用于制备催化剂,以内选择性(87:13 和高达 96:4)获得了高达 81% ee 的相应内环加合物。在类似条件下使用 N,N'-双(3-氯取代的 2-羟基亚苄基)衍生物作为配体显示出高外选择性(高达 95:5)和中等对映选择性。尽管几乎没有观察到非对映选择性,但获得了具有前景的对映选择性水平的内环加合物和外环加合物(高达 >