Asymmetric Carbene C–O Insertion Reaction Using Optically Active Bipyridine-Copper Complex as a Catalyst. Ring Expansion of Oxetanes to Tetrahydrofurans
作者:Katsuji Ito、Tsutomu Katsuki
DOI:10.1246/cl.1994.1857
日期:1994.10
Copper complex of (7R,7R′)-7,7′-di(1-t-butyldimethylsiloxy-1-methylethyl)-6,6′,7,7′-tetrahydro-5H,5′H-2,2′-bi-1,1′-pyrindine (3) was found to be an effective catalyst for asymmetric carbene insertion reaction into the C-O bond of oxetanes. For example, the reaction of dl-2-phenyloxetane and t-butyl diazoacetate in the presence of Cu-3 complex provided trans- and cis-t-butyl 3-phenyltetrahydrofuran-2-carboxylate of 75% ee and 81% ee, respectively.
(7R,7R′)-7,7′-二(1-t-丁基二甲基硅氧基-1-甲基乙基)-6,6′,7,7′-四氢-5H,5′H-2,2′-双-1,1′-吡啶铜复合物(3)被发现是一种有效的催化剂,用于不对称氮气插入反应进入氧杂环的C-O键。例如,dl-2-苯氧杂环与t-丁基二硝基乙酸酯在Cu-3复合物存在下的反应,分别提供了75%和81%对映体过剩的反-和顺- t-丁基 3-苯基四氢呋喃-2-羧酸酯。