New Asymmetric Catalysis by (Salen)cobalt(III) Complexes (Salen=[Bis(salicylidene)ethylenediaminato]={{2,2′-[ethane-1,2-diyl]bis[(nitrilo-N)methylidyne]bis[phenolato-O]}(2−)}) of cis--Structure: Enantioselective Baeyer-Villiger Oxidation of Prochiral Cyclobutanones
作者:Tatsuya Uchida、Tsutomu Katsuki、Katsuji Ito、Suemi Akashi、Ayako Ishii、Tomomi Kuroda
DOI:10.1002/1522-2675(200210)85:10<3078::aid-hlca3078>3.0.co;2-1
日期:2002.10
and used for the enantioselective Baeyer-Villiger oxidation of prochiral cyclobutanones with hydrogen peroxide as terminal oxidant. Both cationic (salen)cobalt(III) and neutral iodo(salen)cobalt(III) complexes 3–5 and 7–12, respectively, all having a chiral binaphthalenediamine unit, were found to be effective catalysts for the enantioselective Baeyer-Villiger oxidation (Tables 1, 3, and 4). In particular
一系列手性(salen)钴(III)配合物(salen=[bis(salicylidene)ethylenediminato]=2,2′-[(ethane-1,2-diyl)bis[(nitrilo-κN)methylidyne]bis)制备了顺式-β结构的[phenolato-κO]}(2-)}),并用于以过氧化氢为末端氧化剂对前手性环丁酮进行对映选择性拜耳-维利格氧化。阳离子 (salen) 钴 (III) 和中性碘 (salen) 钴 (III) 配合物 3-5 和 7-12 分别具有手性联萘二胺单元,被发现是对映选择性 Baeyer-Villiger 氧化的有效催化剂(表 1、3 和 4)。特别是,带有吸电子 F 原子的配合物 8 在 3-芳基环丁酮的反应中表现出良好的对映选择性(75-79% ee)(方案 4)。另一方面,