Mechanism of stereoselective production of trans-1-decalone by electrochemical catalysis in microemulsions

被引：22

作者：

Gao, JX ^{[1
]}

Njue, CK ^{[1
]}

Mbindyo, JKN ^{[1
]}

Rusling, JF ^{[1
]}

机构：

[1] Univ Connecticut, Dept Chem, Storrs, CT 06269 USA

来源：

JOURNAL OF ELECTROANALYTICAL CHEMISTRY | 1999年 / 464卷 / 01期

基金：

美国国家科学基金会;

关键词：

microemulsions; electrochemical catalysis; stereoselectivity; cyclization; vitamin B-12;

D O I：

10.1016/S0022-0728(98)00463-X

中图分类号：

O65 [分析化学];

学科分类号：

070302 ; 081704 ;

摘要：

Microemulsions made from water, oil and surfactant are attractive alternatives to organic solvents for mediated electrochemical synthesis. Cyclization of 2-(4-bromobutyl)-2-cyclohexen-1-one (I) to 1-decalone (2) mediated by an electrochemically generated cobalt(I) complex favored the trans- form over cis-1-decalone by about 93:7 in microemulsions, but poorer stereoselectivity was obtained in organic solvents. Microemulsion composition, surfactant type (cationic or anionic), or chirality of the mediator did not significantly influence the trans/cis ratio of 1-decalone. Selective formation of trans-1-decalone in microemulsions is attributed to equilibration of isomers via keto-enol tautomerization catalyzed by hydroxide ions formed by co-electrolysis of water during the reaction. Trans-1-decalone was efficiently produced in 2 h electrolyses in microemulsions with large volume fractions of water. Organic solvents with trace amounts of water gave little stereoselectivity over similar periods, but longer equilibration times produced larger proportions of trans-1-decalone. (C) 1999 Elsevier Science S.A. All rights reserved.

引用

页码：31 / 38

页数：8

共 32 条

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[2] Isopinocampheylchloroborane: A promising new reagent for asymmetric cyclic hydroboration. A simple procedure to convert 1-allyl-1-cyclohexene into trans-1-decalone of >=99% optical purity [J].