Design and Preparation of 3,3‘-Disubstituted 2,2‘-Bis(oxazolyl)-1,1‘-binaphthyls (boxax): New Chiral Bis(oxazoline) Ligands for Catalytic Asymmetric Wacker-Type Cyclization
作者:Yasuhiro Uozumi、Hirokazu Kyota、Kazuhiko Kato、Masamichi Ogasawara、Tamio Hayashi
DOI:10.1021/jo982104m
日期:1999.3.1
promoted by the oxazolyl groups. The 3,3'-disubstituted boxax ligands showed much higher enantioselectivity than the 3,3'-unsubstituted ones in the palladium(II)-catalyzed Wacker-type cyclization of an o-allylphenol. The cyclization of (E)-2-(2-methyl-2-butenyl)phenol (10) in the presence of a cationic palladium catalyst coordinated with (S)-2,2'-bis(4,4-dimethyloxazol-2-yl)-3,3'-bis(methoxycarbonyl)-1
制备了新的旋光的2,2'-双(恶唑基)-1,1'-联萘(boxax),其在C3和C3'位置带有各种取代基(甲氧基羰基,三甲基甲硅烷基,(二甲基氨基)羰基,甲酰基和碘基)恶唑基促进了邻位锂化。在钯(II)催化的邻烯丙基苯酚的Wacker型环化反应中,3,3'-双取代的Boxax配体比3,3'-未取代的配体具有更高的对映选择性。在与(S)-2,2'-双(4,4-二甲基恶唑-2)配位的阳离子钯催化剂存在下(E)-2-(2-甲基-2-丁烯基)苯酚(10)的环化-基)-3,3′-双(甲氧基羰基)-1,1′-联萘基得到96%ee的(S)-2-乙烯基-2-甲基-2,3-二氢苯并呋喃。