Highly Selective, Recyclable Epoxidation of Allylic Alcohols with Hydrogen Peroxide in Water Catalyzed by Dinuclear Peroxotungstate
作者:Keigo Kamata、Kazuya Yamaguchi、Noritaka Mizuno
DOI:10.1002/chem.200400352
日期:2004.10.4
of oxygen to the carbon-carbon double bond, and the regeneration of the dinuclear peroxotungstate with hydrogenperoxide is proposed. The reaction rate shows first-order dependence on the concentrations of allylic alcohol and dinuclear peroxotungstate and zero-order dependence on the concentration of hydrogenperoxide. These results, the kinetic data, the comparison of the catalytic rates with those
双核过氧钨酸钾K2 [[W(= O)(O2)2(H2O) ] 2(mu-O)] 2 H 2 O(I)。该催化剂易于回收,同时保持其催化性能。提出了催化反应机理,包括交换水配体以形成钨醇盐物种,然后将氧插入碳-碳双键,并用过氧化氢再生双核过氧钨酸盐。反应速率显示出对烯丙基醇和双核过氧钨酸盐的浓度的一级依赖性,而对过氧化氢的浓度则呈零级依赖性。这些结果,动力学数据,
A Highly Chemoselective, Diastereoselective, and Regioselective Epoxidation of Chiral Allylic Alcohols with Hydrogen Peroxide, Catalyzed by Sandwich-Type Polyoxometalates: Enhancement of Reactivity and Control of Selectivity by the Hydroxy Group through Metal−Alcoholate Bonding
作者:Waldemar Adam、Paul L. Alsters、Ronny Neumann、Chantu R. Saha-Möller、Dorit Sloboda-Rozner、Rui Zhang
DOI:10.1021/jo0266386
日期:2003.3.1
Sandwich-type polyoxometalates (POMs), namely [WZnM2(ZnW9O34)2]q- [M = Mn(II), Ru(III), Fe(III), Pd(II), Pt(II), Zn(II); q = 10-12], are shown to catalyze selectively the epoxidation of chiral allylicalcohols with 30% hydrogen peroxide under mild conditions (ca. 20 degrees C) in an aqueous/organic biphasic system. The transition metals M in the central ring of polyoxometalate do not affect the reactivity
Regio- and Diastereoselective Catalytic Epoxidation of Acyclic Allylic Alcohols with Methyltrioxorhenium: A Mechanistic Comparison with Metal (Peroxy and Peroxo Complexes) and Nonmetal (Peracids and Dioxirane) Oxidants
作者:Waldemar Adam、Catherine M. Mitchell、Chantu R. Saha-Möller
DOI:10.1021/jo9902289
日期:1999.5.1
Geraniol and its 1-methyl derivative (regiochemical probes) and a set of methyl- and tert-butyl-substituted chiral allylicalcohols (stereochemical probes) have been used to elucidate the mechanism of the MTO-catalyzed epoxidation of allylicalcohols. The regiochemical probes are preferentially epoxidized at the unfunctionalized double bond by these MTO-based oxidants, which establishes that MTO/UHP
Chemoselective C−H Oxidation of Alcohols to Carbonyl Compounds with Iodosobenzene Catalyzed by (Salen)chromium Complex
作者:Waldemar Adam、Feyissa Gadissa Gelalcha、Chantu R. Saha-Möller、Veit R. Stegmann
DOI:10.1021/jo9913457
日期:2000.4.1
secondary alcohols with benzylically and allylically activated C-H bonds are chemoselectively oxidized to the corresponding carbonylcompounds by the (salen)Cr(III) complex I as the catalyst and iodosobenzene as the oxygen source; the oxidizing species is the Cr(V) oxo complex. Allylicalcohols with fully substituted double bonds give appreciable amounts of epoxides besides the C-H oxidation products
Chiral Hydroperoxides as Oxygen Source in the Catalytic Stereoselective Epoxidation of Allylic Alcohols by Sandwich-Type Polyoxometalates: Control of Enantioselectivity through a Metal-Coordinated Template
作者:Waldemar Adam、Paul L. Alsters、Ronny Neumann、Chantu R. Saha-Möller、Dieter Seebach、Albert K. Beck、Rui Zhang
DOI:10.1021/jo034923z
日期:2003.10.1
The epoxidation of allylic alcohols is shown to be efficiently and selectively catalyzed by the oxidatively resistant sandwich-type polyoxometalates, POMs, namely [WZnM(2)(ZnW(9)O(34))(2)](q)(-) [M = OV(IV), Mn(II), Ru(III), Fe(III), Pd(II), Pt(II), Zn(II); q = 10-12], with organic hydroperoxides as oxygen source. Conspicuous is the fact that the nature of the transition metal M in the central ring