ether-oxygen to the stereogenic quaternary carbon center of the oxirane ring had a profound influence on the enantioselectivity, and several oxiranes were resolved with good to excellent selectivities. The enantiomerically enriched epoxides and vicinal diols thus obtained contain a useful “synthetic handle” in their side chain, which allows their use as buildingblocks in asymmetric synthesis.
作者:Jae-Chul Jung、Rajashaker Kache、Kimberly K. Vines、Yan-Song Zheng、Panicker Bijoy、Muralikrishna Valluri、Mitchell A. Avery
DOI:10.1021/jo048742o
日期:2004.12.1
A convergent, totalsynthesis of epothilonesB (2) and D (4) is described. The key steps are Normant coupling to establish the desired (Z)-stereochemistry at C12−C13, Wadsworth−Emmons olefination of methyl ketone 28 with the phosphonate ester 8, diastereoselective aldol condensation of aldehyde 5 with the enolate of keto acid derivatives to form the C6−C7 bond, selective deprotection of acid 52, and
aqueous catalytic method for selective epoxidation of olefins and oxidation of saturated hydrocarbons to ketones using aqueous solution of tetra-n-butylammonium peroxomonosulfate (TBAOX) containing water-insoluble copper (II) phthalocyanine nanoparticles has been developed. No surfactants, additives, toxic reagents or solvents were involved. The impressive turnover numbers obtained for CuPc in this oxidation
Nanomagnet‐Supported Partially Brominated Manganese–Porphyrin as a Promising Catalyst for the Selective Heterogeneous Oxidation of Hydrocarbons and Sulfides in Water
excellent selectivity under the influence of the magnetically separable catalyst. Sulfoxides could also be selectively produced in a mixture of water and ethanol, which makes the title methodology a good alternative for both sulfoxide and sulfone production. The separation and recycling of the catalyst and the byproduct of the oxidant were simple, effective, and economic in this clean oxidation method
通过胺官能团将 [Mn(Br2TPP)OAc] 配合物配位锚定在二氧化硅包覆的磁性纳米粒子 (Fe3O4@SiO2, SMNP) 上,制备了一种新型的磁性可回收卟啉催化剂。通过粉末 X 射线衍射、透射电子显微镜、扫描电子显微镜和 FTIR 光谱对多相催化剂进行了表征。通过热重 (TG) 分析和电感耦合等离子体原子发射光谱测定磁性载体上的催化剂负载。据估计,催化剂纳米颗粒的直径小于 10 nm。TG 曲线表明纳米催化剂在高达近 350 °C 的温度下是热稳定的,表现出很高的热稳定性。在过氧化单硫酸四正丁基铵(n-Bu4NHSO5,TBAOX)的水溶液中,烯烃的环氧化和饱和烃氧化成相应的酮以及硫化物氧化成砜,在磁性的影响下以优异的选择性得到有效增强。可分离的催化剂。亚砜也可以在水和乙醇的混合物中选择性地生产,这使得标题方法成为亚砜和砜生产的良好替代方案。在这种清洁氧化方法中,催化剂和氧化剂副产
The catalytic efficiency of Fe-porphyrins supported on multi-walled carbon nanotubes in the heterogeneous oxidation of hydrocarbons and sulfides in water
作者:Abdolreza Rezaeifard、Maasoumeh Jafarpour
DOI:10.1039/c3cy00554b
日期:——
Novel recoverable biomimetic catalysts were prepared by the coordinative anchoring of an iron(III) meso-tetraphenyl porphyrin complex [Fe(TPP)Cl] and some derivatives on the activated multi-walled carbon nanotube (AMWCNT) via hydroxyl functionality (Fe-Por–AMWCNT). The simple heterogeneous catalyst [Fe(TPP)Cl–MWCNT] was characterized by powder X-ray diffraction (XRD), transmission electron microscopy