Asymmetric Weitz-Scheffer epoxidation of conformationally flexible and fixed enones with sterically demanding hydroperoxides mediated by optically active phase-transfer catalysts

被引：34

作者：

Adam, W ^{[1
]}

Rao, PB ^{[1
]}

Degen, HG ^{[1
]}

Saha-Möller, CR ^{[1
]}

机构：

[1] Univ Wurzburg, Inst Organ Chem, D-97074 Wurzburg, Germany

来源：

TETRAHEDRON-ASYMMETRY | 2001年 / 12卷 / 01期

关键词：

D O I：

10.1016/S0957-4166(00)00497-3

中图分类号：

O61 [无机化学];

学科分类号：

070301 ; 081704 ;

摘要：

The asymmetric Weitz-Scheffer epoxidation of alpha,beta -enones 1a-d with hydroperoxides 2 and mediated by cinchonine-and cinchonidine-derived phase-transfer catalysts (PTCs)3 affords the optically active epoxides 4 with moderate to very good e.e.s and in near quantitative yields. For the conformationally flexible enone 1b, the enantioselectivity decreases with more sterically demanding tertiary hydroperoxides, while an opposite trend is observed for the rigid s-cis-enone I. With the bulky cumyl hydroperoxide 2c and the PTC 3c, the enone 1 was converted to the epoxide 4c with the highest enantioselectivity (95% e.e.) so far observed for PTC-catalyzed epoxidations using hydroperoxides as oxygen sources. (C) 2001 Elsevier Science Ltd. All rights reserved.

引用

页码：121 / 125

页数：5

共 13 条

[1] Metal-template effect in the asymmetric Weitz-Scheffer epoxidation of α,ß-enones by an optically active hydroperoxide [J].

Adam, W ;

Rao, PB ;

Degen, HG ;

Saha-Möller, CR .

JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 2000, 122 (23) :5654-5655

[2] Asymmetric epoxidation of α,β-unsaturated ketones under phase-transfer catalyzed conditions [J].

Arai, S ;

Tsuge, H ;

Shioiri, T .

TETRAHEDRON LETTERS, 1998, 39 (41) :7563-7566

[3] Catalytic asymmetric epoxidation of alpha,beta-unsaturated ketones promoted by lanthanoid complexes [J].

Bougauchi, M ;

Watanabe, S ;

Arai, T ;

Sasai, H ;

Shibasaki, M .

JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 1997, 119 (09) :2329-2330

[4] Mechanism and conditions for highly enantioselective epoxidation of α,β-enones using charge-accelerated catalysis by a rigid quaternary ammonium salt [J].

Corey, EJ ;

Zhang, FY .

ORGANIC LETTERS, 1999, 1 (08) :1287-1290

[5] Asymmetric epoxidation of chalcones with chirally modified lithium and magnesium tert-butyl peroxides [J].

Elston, CL ;

Jackson, RFW ;

MacDonald, SJF ;

Murray, PJ .

ANGEWANDTE CHEMIE-INTERNATIONAL EDITION IN ENGLISH, 1997, 36 (04) :410-412

[6]

Enders D, 1997, LIEBIGS ANN-RECL, P1101

[7]

HELDER R, 1976, TETRAHEDRON LETT, P1831

[8] Phase-transfer catalysed asymmetric epoxidation of enones using N-anthracenylmethyl-substituted cinchona alkaloids [J].

Lygo, B ;

Wainwright, PG .

TETRAHEDRON, 1999, 55 (20) :6289-6300

[9] Asymmetric synthesis of the mC7N core of the manumycin family:: Preparation of (+)-MT35214 and a formal total synthesis of (-)-alisamycin [J].

Macdonald, G ;

Alcaraz, L ;

Lewis, NJ ;

Taylor, RJK .

TETRAHEDRON LETTERS, 1998, 39 (30) :5433-5436

[10] DOUBLE ASYMMETRIC-SYNTHESIS AND A NEW STRATEGY FOR STEREOCHEMICAL CONTROL IN ORGANIC-SYNTHESIS [J].

MASAMUNE, S ;

CHOY, W ;

PETERSEN, JS ;

SITA, LR .

ANGEWANDTE CHEMIE-INTERNATIONAL EDITION, 1985, 24 (01) :1-30

← 1 2 →