Recent progress in asymmetric two-center catalysis

Recent progress using two types of enantioselective two-center catalysts, Lewis acid-Br?nsted base and Lewis acid-Lewis base bifunctional complexes, is described. The first part of this review discusses improvements in the syn-selective direct catalytic enantioselective aldol reaction and 1,4-addition reaction of a 2-hydroxyacetophenone derivative using a Zn-linked-BINOL complex. In the second part, we describe the development of catalysts displaying Lewis acidity and Lewis basicity in a catalytic enantioselective cyanosilylation of aldehydes and the logical extension to a tetrasubstituted carbon synthesis through a Reissert-type reaction and a cyanosilylation of ketones.     

催化不对称Michalel加成反应的新进展

总结了近年催化不对称Michael加成反应的新方法，包括手性金属络合物催化 的反应，呈手性Lewis酸性的手性金属络合物促进的不对称加成，手性冠醚络合物 催化的反应及其它催化反应。     

酮的不对称还原

按反应类型分类,综述了酮的不对称还原方法及其近年来的新进展。     

Recent progress in copper catalyzed asymmetric Henry reaction

Henry reaction is one of the most classical reactions to construct synthetically useful product nitro alcohol, which as a privileged skeleton is widely distributed in various pharmaceuticals. This review summarizes the recent progress of copper-catalyzed asymmetric Henry reaction from 2011 to 2016. The significant progress that has been made in this area will be highlighted and some of challenges that the author believes may be hindering further progress will be revealed.     

Recent progress of MXenes as the support of catalysts for the CO oxidation and oxygen reduction reaction

MXenes,the new family of two-dimensional(2D) transition metal carbides/nitrides,can serve as the substrate materials for the catalysts due to the large specific surface area,tunable electronic structures and thermal stability.The first 2D layered MXene,Ti₃C₂,was successfully obtained by selective etching of the A element from the MAX phases using hydrofluoric acid(HF) at room temperature in 2011.In this review,we summarize the preparation,structure of MXenes and discuss the...     

Recent advances in asymmetric copper allylic oxidation of olefins

This review deals with the recent advances in asymmetric copper allylic oxidation of olefins. An exhaustive analysis of the results has been realized showing the limitation of the different asymmetric catalytic systems used.     

Recent developments in asymmetric reduction of ketones with biocatalysts

Herein we review recent advances in the asymmetric reduction of ketones by biocatalysts. Included are discussions on recent developments in methodologies to control enantioselectivities of catalytic reactions, and examples of practical applications that reduce various types of ketones are also shown.     

模拟醛缩酶催化不对称直接Aldol反应新进展

对天然醛缩酶的作用机理进行了一般性阐述，在此基础上详细回顾了近几年对 两类醛缩酶的模拟催化不对称直接Aldol反应，并对其发展前景作了展望。     

Recent progress on direct catalytic asymmetric vinylogous reactions

Direct catalytic asymmetric vinylogous reaction serves as a powerful tool to introduce stereocenter(s) at the γ- or/and even more remote position(s) of the vinylogous products in an atom-economical and efficient way. A variety of direct catalytic asymmetric vinylogous reactions with broad substrate scope and mild reaction conditions has been developed. Both metal catalysis and organocatalysis contributed in this field and led to the vinylogous products in high stereoselectivity. These vinylogous reactions provided efficient pathways for the synthesis of highly functionalized optically pure compounds, especially these with potential biological activity and pharmacological activity. This digest paper mainly focuses on the most recent developments in this field, including both nucleophilic addition and nucleophilic substitution.     

醚选择性氧化研究的新进展

本文综述了近年来醚选择性氧化研究的新进展. 主要介绍了铬(Ⅵ)类试剂, 过氧化物, 硝酸,氧和臭氧等各类氧化剂对选择性氧化以及醚的阳极电氧化研究状况 .     

烯烃不对称双羟化及其反应机理的研究进展

本文综述了近年来四氧化锇催化烯烃不对称双羟化及其反应机理的研究进展。Sharpless等对烯烃双羟化机理的透彻研究导致了不对称双羟化方法的优化。     

Recent development of heterogeneous catalysis in ring-opening,biocatalysis, and selective partial oxidation reactions on metal oxides

In this review article, we analyze the state of the art and future developments in three important domains of heterogeneous catalysis, namely ring opening, biocatalysis, and partial oxidation on metal oxides. After recollecting the scientific bases of each domain, we consider several examples, some recent improvements/developments, and some prospective views.     

Recent progress in advanced core-shell metal-based catalysts for electrochemical carbon dioxide reduction

Electrochemical carbon dioxide reduction（CO₂RR） plays an important role in solving the problem of high concentration of CO₂in the atmosphere and realizing carbon cycle. Core-shell structure has many unique features including tandem catalysis, lattice strain effect, defect engineering, which exhibit great potential in electrocatalysis. In this review, we focus on the advanced core-shell metal-based catalysts（CMCs） for electrochemical CO₂RR. The recent progress of ...     

光催化选择性氧化还原体系在有机合成中的研究进展

21世纪,化学研究的一个主要目标是发展一种高效能技术,用于取代那些对环境有害的耗能过程.光催化选择性氧化还原体系的出现和应用极大地满足了人们对能源和环境的要求.在光催化选择性氧化还原体系中,反应发生所需要的条件比传统催化温和,同时它也避免了一些强氧化剂和危险还原性物质的使用,通过优化反应环境可以实现对某种目标产物的高选择性,从而为有机合成提供了一种绿色、节能的途径,成为21世纪最具潜力的绿色有机化学技术.本文重点阐述了光催化选择性氧化还原体系在有机合成领域中的重要进展,并对其存在的问题及相关领域的发展趋势作了展望.     

Recent advances in biocatalysis by directed enzyme evolution

Naturally occurring enzymes are remarkable biocatalysts with numerous potential applications in industry and medicine. However, many of their catalyst properties often need to be further tailored to meet the specific requirements of a given application. Within this context, directed evolution has emerged over the past decade as a powerful tool for engineering enzymes with new or improved functions. This review summarizes recent advances in applying directed evolution approaches to alter various enzyme properties such as activity, selectivity (enantio- and regio-), substrate specificity, stability, and solubility. Special attention will be paid to the creation of novel enzyme activities and products by directed evolution.     

Recent progress in the immobilization of catalysts for selective oxidation in the liquid phase

Reliable strategies are presented for the immobilization of molecular catalysts for selective oxidation in the liquid phase. Besides classical strategies such as ion exchange or covalent anchoring, new approaches are emerging, e.g. based on supported ionic-liquid phases or on incorporation of the active centre in a coordination polymer or a metal-organic framework.     

铂族金属催化剂低温 CO氧化研究近期进展

CO氧化可能是多相催化领域最常见的反应,它不仅能作为探针反应研究催化剂结构、反应活性位等,而且在诸多实际过程如空气净化、汽车尾气污染物控制、燃料电池所用氢源净化等扮演重要角色.最早的 CO氧化催化剂为霍加拉特剂,其组分主要为 CuO与 MnO2混合氧化物,然而在实际应用过程中存在低温活性低、吸湿易失活等缺点.1987年, Haruta等发现湿化学法制备的氧化物负载 Au催化剂表现出非常高的低温 CO氧化活性及耐水稳定性,其 Au粒子以纳米尺度分散,进而引发了催化研究领域的“淘金热”及纳米催化研究热潮.而 CO氧化通常作为考察 Au催化剂结构性质的探针反应,也成为考核其它金属催化剂是否具有高活性的判据之一. Pt族金属上 CO氧化反应从 Langmuir等研究开始至今已有100多年,然而低温下该金属催化剂活性与 Au催化剂相比要低一个数量级.本质原因为 Pt族金属上 CO吸附较强, O2吸附与活化受到抑制,而该步骤被认为是 CO氧化的速控步,因而表现出较低的催化活性.通常 Pt族金属催化剂需要100oC以上 CO才能脱附, O2进而得以吸附.目前研究人员采取多种策略,其基本原则为削弱 Pt族金属上 CO吸附强度或者提供其它活性位供 O2吸附与活化.本综述将概括近十年来Pt族金属催化剂 CO氧化研究进展,主要总结室温甚至超低温条件下的研究成果.高活性 CO氧化催化剂主要是通过采用可还原氧化物为载体或助剂,或者改变催化剂表面性质如使表面富 OH基物种来形成. Au催化剂的研究发现,改变金属粒子尺寸极有可能获得不同寻常的催化性能,而常规的 Pt族金属催化剂研究主要是在纳米尺度.近期人们发现逐渐减小 Pt族金属粒子尺寸,从纳米到亚纳米甚至单原子时,其电荷状态逐渐呈正价形式,这有利于削弱其 CO吸附强度.此外,可通过增强金属载体间的相互作用,改变金属载体接触方式,如从核壳到交叉结联结构,构筑出更多的金属载体界面,使得 O2更容易吸附与活化或稳定更多的 OH基物种进而在此界面与吸附的 CO反应.伴随着表征技术的发展, CO氧化机理的认识也更加深入,这给催化剂的设计带来更多新的思路.(1)改变 CO吸附活化位,将 CO吸附活化位从金属转移到载体上,从而大大降低 CO吸附强度,活化的 CO物种在反应过程中容易溢流到金属载体界面处,这甚至有利于超低温度下(–100oC左右) CO氧化.(2)改变 O2活化形式. O2通常在 Pt族金属上容易以解离氧原子形式存在,通过改变载体、金属载体界面性质使得 O2以分子氧形式活化,如形成超氧或过氧物种,这有利于降低 CO氧化的活化能垒,进而提高其低温甚至超低温下 CO氧化活性.今后,设计并合成出在超低温度下能够氧化 CO的 Pt族金属催化剂将成为 CO氧化催化剂研究的重要方向之一.