手性钯络合物催化下2-硝基环酮的不对称烯丙基化反应

在用氮杂冠醚改良的手性二茂铁膦与钯的络合物催化下, 2-硝基环酮可进行不对称烯丙基化反应. 讨论了配位基的形状, 反应物的构造, 碱的类型以及反应时间对反应速率和立体选择性的影响. 通过增加反应的空间位阻改进了反应的立体选择性 .     

Synthesis of chiral vinylic sulfoxides by Pd-catalyzed asymmetric sulfinylzincation

Novel asymmetric sulfinylzincation of alkynoates has been accomplished via a Pd-catalyzed sulfinylzincation using 1-alkynyl sulfoxides bearing chiral auxiliaries as a sulfinylating reagent. The reaction proceeded in a highly syn-selective fashion, giving the (E)-β-sulfinyl α,β-unsaturated ester exclusively. Among the chiral sulfinylating reagents tested, an isoborneol-type compound (Rs)-4 showed the best results in terms of both yield and diastereoselectivity. As a result of optimization of the reaction, the selectivity was improved up to 92:8 dr, and stereochemistry of the newly formed sulfur stereogenic center was revealed as (Ss)-configuration.     

Design and synthesis of chiral 1,10-phenanthroline ligand,and application in palladium catalyzed asymmetric 1,4-addition reactions

Pd-catalyzed asymmetric 1,4-addition of phenylboronic acid to α,β-unsaturated carbonyl compounds was developed using chiral 1,10-phenanthroline derivative as ligand. Good yields (up to 97%), and high enantioselectivities (up to 97% ee) were achieved.     

Catalytic activity of chiral chelating N-heterocyclic carbene palladium complexes towards asymmetric allylic alkylation

Abstract

The catalytic activity of a series of chiral heteroaryl coordinated chelating N-heterocyclic carbene (NHC) palladium complexes towards asymmetric allylic alkylation (AAA) were presented here. The effects of different N-substituents, NHC backbones and chelate rings on the catalytic activity and the enantioselectivity of the alkylation of (E)-1,3-diarylallyl acetates with dialkyl malonate were investigated. The results showed that, under the optimized conditions, complexes 3a, 3b, and 3i carrying the pyridinyl-coordinated five-membered chelate ring showed high catalytic activity and chiral induction efficiency. The corresponding alkylated products were obtained in high yields with moderate ee. Furthermore, it was found that the substituents of (E)-1,3-diarylallyl acetates and the type of the nucleophile affect the results as well.     

不对称催化反应在手性药物合成中的应用进展

本文从官能团的转换和碳硫键形成的角度概述了我国近年来在不对称催化反应领域的研究进展,特别是在手性药物及其中间体合成中的应用进展。参考文献42篇。     

Catalytic asymmetric Mannich-type reactions of fluorinated ketoesters with N-Boc aldimines in the presence of chiral palladium complexes

The catalytic enantioselective Mannich reaction promoted by chiral palladium complexes is described. The treatment of α-fluoro-β-ketoesters with N-Boc-aldimines under mild reaction conditions afforded the corresponding β-aminated α-fluoro-β-ketoesters with excellent enantioselectivities (up to 99% ee).     

催化不对称硅氧化反应研究进展

综述了催化不对称硅氢化反应的研究进展情况，重点介绍了最近十年来手性催 化剂配体的研究情况。     

手性助剂诱导催化不对称Strecker反应研究进展

亚胺的不对称Strecker反应是合成α-氨基酸化合物的重要途径之一,一般在手性助剂的诱导下进行.近年来,用于诱导不对称Strecker反应的各类手性助剂的研究受到广泛关注.本文综述了α-苯乙胺、α-氨基酸、α-氨基酸衍生的酰胺、α-苯甘氨醇、亚磺酰基亚胺、糖胺、肼等七类化合物作为手性助剂在不对称Strecker反应中的应用研究现状,就该研究领域存在的问题进行了分析,并对其前景进行了展望.     

Recent topics on catalytic asymmetric 1,4-addition

Catalytic asymmetric 1,4-addition (conjugate addition; Michael addition) is one of the most powerful methods for carbon-carbon bond formation. Following the first efficient catalyst system developed by Feringa, which is composed of Cu(OTf)₂ and phosphoramidite with dialkylzincs, a variety of chiral catalysts have been reported for the catalytic asymmetric conjugate addition. In this digest review, we will first summarize novel chiral ligands that work efficiently for cyclic and acyclic enones and demonstrate the wide applicability of Michael acceptors. We will also introduce unique phenomena that include the nonlinear effect and reversal of enantioselectivity. Organomagnesium reagents have also been used instead of organozincs. Finally, we introduce the recent examples of the synthesis of natural products based on the catalytic asymmetric reaction. The rare experimental studies into the mechanism of copper-catalyzed 1,4-addition reported by Kitamura and Noyori’s group are also introduced.     

Screening of a modular sugar-based phosphite-oxazoline ligand library in asymmetric Pd-catalyzed heck reactions

We have synthesised a library of phosphite-oxazoline ligands derived from readily available D-glucosamine. These ligands have been successfully screened in the palladium-catalysed Heck reaction of several substrates with high regio- (up to 99 %) and enantioselectivities (ee's up to 99 %) as well as with improved activities under standard thermal conditions. The results indicate that the catalytic performance is highly affected by the oxazoline and biarylphosphite substituents and the axial chirality of the biaryl moiety of the ligand. The Heck reactions were also performed under microwave irradiation conditions, allowing a considerably shorter reaction time (full conversion in minutes) maintaining the excellent regio- and enantioselectivities.     

新型手性环状胺膦配体的设计合成及在酮的不对称还原中的应用

新型手性配体的设计合成是不对称催化研究的重要内容,其中手性胺膦配体因同时含有"软"的磷原子和"硬"的氮原子而具有丰富的配位化学性能和优秀的不对称诱导能力.本文总结了本研究组最近设计合成的手性环状胺膦配体的制备、表征及其在铁催化酮的不对称还原中的应用.手性1,2-环己二胺与双(2-甲酰基苯基)苯基膦通过[2+2]环缩合反应能够顺利获得手性22元环的亚胺膦配体21,该配体经Na BH4还原后生成大环胺膦配体22.利用手性大环胺膦配体22与Fe3(CO)12原位生成的催化体系,能够高活性、高对映选择性地实现包括杂环芳香酮在内50多种酮的不对称转移氢化和不对称氢化反应,其S/C(底物与催化剂的摩尔比)最高可达5000:1,产物手性芳香醇的光学纯度高达99%ee.     

手性炔丙醇的不对称催化合成研究进展

手性炔丙醇是一种重要中间体化合物,作为合成多种光学活性化合物的重要合成前体受到学者们广泛关注。目前通过酮的不对称催化反应合成手性炔丙醇的研究开发具有极大发展前景,因此本文围绕酮类化合物的不对称催化反应来进行综述,结合相关反应最新研究进展,全面总结并分类了不对称催化还原、催化不对称加成等反应类型,介绍了合成不同结构手性炔丙醇的新思路,并对酮的不对称催化反应在未来能成为工业化重要生产途径作出展望。     

Modular phosphite-oxazoline/oxazine ligand library for asymmetric pd-catalyzed allylic substitution reactions: scope and limitations-origin of enantioselectivity

A library of phosphite-oxazoline/oxazine ligands L1-L15 a-h has been synthesized and screened in the Pd-catalyzed allylic substitution reactions of several substrate types. These series of ligands can be prepared efficiently from easily accessible hydroxyl amino acid derivatives. Their modular nature enables the substituents/configurations in the oxazoline/oxazine moiety, alkyl backbone chain and in the biaryl phosphite moiety to be easily and systematically varied. By carefully selecting the ligand components, therefore, high regio- and enantioselectivities (ee values up to 99 %) and good activities have been achieved in a broad range of mono- and disubstituted linear hindered and unhindered liner and cyclic substrates. The NMR studies on the Pd-pi-allyl intermediates provide a deeper understanding about the effect of the ligand parameters on the origin of enantioselectivity. It also indicates that the nucleophilic attack takes place predominantly at the allylic terminal carbon atom located trans to the phosphite moiety.     

BINAP versus BINAP(O) in asymmetric intermolecular Mizoroki-Heck reactions: substantial effects on selectivities

2,2′‐Bis(diphenylphosphino)‐1,1′‐binaphthyl (BINAP) was employed as chiral ligand in the enantioselective intermolecular Mizoroki–Heck reaction, whereas the use of cognate BINAP(O) (monooxidized BINAP) is unprecedented. The regio‐ and enantioselectivity of the arylation of representative cyclic alkenes changes dramatically in the presence of hemilabile BINAP(O) instead of BINAP. The arylation of 2,3‐dihydrofuran is perfectly regiodivergent (98:2 versus 0:100) and the arylation of cyclopentene is only enantioselective with BINAP(O) [60 versus 10 % enantiomeric excess (ee)]. Use of [Pd₂(dba)₃] ? dba (dba=dibenzylideneacetone) instead of Pd(OAc)₂ produces as high as 86 % ee in the arylation of cyclopentene.     

手性金属催化剂在不对称环丙烷化反应中的应用进展

手性金属催化剂在不对称环丙烷化反应中的应用一直是不对称合成领域的一个热点。对三十多年来的这一领域的手性金属催化剂的发展作了详细的归纳和评述。