手性亚砜的合成及其在不对称合成中的应用

本文综述了手性亚砜的合成。由于亚砜结构上的特征以及与金属离子的络合能力,使手性亚砜在不对称合成中具有强烈的诱导作用,使它成为进行不对称合成的一个手段。本文列举了它在不对称合成中的应用情况。     

Synthesis of a Stimuli‐Responsive P‐Chiral Polymer with Chiral Phosphorus Atoms and Azobenzene Moieties in the Main Chain

A reaction of the P‐chiral compound (S,S)‐1,2‐bis(boranato(tert‐butyl)methylphosphino)ethane with an azobenzene derivative gave stimuli‐responsive polymers with P‐chiral phosphines in the main chain. This is the first example of a stimuli‐responsive P‐chiral polymer. The polymer isomerized from the trans to the cis form upon UV irradiation and reverted to the trans form reversibly. The polymer was able to coordinate to platinum, and the resulting polymer complex exhibited the Cotton effect owing to the chirality of the phosphorus atoms. The structure of the P‐chiral polymer obtained could be changed reversibly by light and thermal stimuli, and the polymer chain was induced to rotate helically when complexed with transition metals through the chiral phosphorus atoms.     

Construction of Axially Chiral Compounds via Central‐to‐Axial Chirality Conversion

Central‐to‐axial chirality conversion represents a fascinating class of chemical processes consisting of the destruction of stereogenic centers and the simultaneous installation of axial chiral elements, which provides efficient methods for the preparation of axially chiral compounds. Using the strategy, a wide range of axially chiral compounds, including biaryls, heterobiaryls, aromatic amides, allenes and vinyl arenes, have been synthesized with high efficiency and excellent enantioselectivity. In addition, central‐to‐axial chirality conversion strategy has been applied to the synthesis of natural products. The strategy has undoubtedly become and will continue to be a hot research topic in the field of asymmetric catalysis and synthesis. In this minireview, we selected some examples to introduce the developments and trends in the central‐to‐axial chirality conversion strategy up to April 2020.     

Synthesis of Chiral Exocyclic Amines by Asymmetric Hydrogenation of Aromatic Quinolin‐3‐amines

Asymmetric hydrogenation of aromatic quinolin‐3‐amines was successfully developed with up to 94 % enantiomeric excess (ee). Introduction of the phthaloyl moiety to the amino group is crucial to eliminate the inhibition effect caused by the substrate and product, to activate the aromatic ring, and to improve the diastereoselectivity. This new methodology provides direct and facile access to chiral exocyclic amines. Notably, this report is the first on the highly enantioselective hydrogenation of aromatic amines.     

Helical Mechanoclinic Deformation of Main‐Chain Chiral Smectic Elastomers

The helical mechanoclinic deformation of a main‐chain chiral smectic elastomer, which is prepared by a crosslinking reaction under twist deformation, is investigated. The twist deformation induces a layer tilt angle that depends on the handedness of twist. The layer tilt angle in the right‐handedly twisted elastomer, of which the handedness is consistent with that of the helix in the SmC* phase of the non‐crosslinked backbone polymer, is estimated to be up to 16° at room temperature, although that in the left‐handedly twisted elastomer is less than several degrees. The experiments provide evidence of chiral coupling between tilt and twist for helical mechanoclinic deformation in the chiral smectic system.

     

不对称催化反应在手性农药不对称合成中的一些应用

近十多年来，不对称催化反应在单一手性农药研发中的应用渐渐引起人们的关 注，结合自己的研究对这一领域的不对称催化反应及手性催化剂的发展进行了归纳 总结。     

Control of the Alternating Sequence for N‐Isopropylacrylamide (NIPAM) and Methacrylic Acid Units in a Copolymer by Cyclopolymerization and Transformation of the Cyclopendant Group

An alternating copolymer of methacrylic acid and N‐isopropyl acrylamide (NIPAM) was synthesized by selective cyclopolymerization of a special divinyl monomer and transformation of repeating cyclo‐units in the resultant cyclopolymer. Crucial to the breakthrough is the monomer design in view of two types of cleavable bonds (3° ester and activated ester) in the pendant group of the monomer and the lower reactivity ratio of the two double bonds (methacrylate and electron‐poor acrylate) for the polymerizable groups. The thus‐obtained cyclopolymer was transformed into the alternating copolymer by transformation of the activated ester into amide by isopropyl amine and cleavage of the 3° ester by trifluoroacetic acid. The resultant copolymer showed thermal and pH response in aqueous solution that was different from the 1:1 random copolymer as well as the homopolymers.     

Base‐Dependent Stereodivergent Intramolecular Aza‐Michael Reaction: Asymmetric Synthesis of 1,3‐Disubstituted Isoindolines

The nucleophilic addition (A_N) / intramolecular aza‐Michael reaction (IMAMR) process on Ellman’s tert‐butylsulfinyl imines, bearing a Michael acceptor in the ortho position, is studied. This reaction affords 1,3‐disubstituted isoindolines with a wide range of substituents in good yields and diastereoselectivities. Interestingly, careful choice of the base for the aza‐Michael step allows either the cis or the trans diastereoisomers to be exclusively obtained. This stereodivergent cyclization has enabled the synthesis of C₂‐symmetric bisacetate‐substituted isoindolines. In addition, bisacetate isoindolines bearing two well‐differentiated ester moieties are also noteworthy because they may allow for the orthogonal synthesis of β,β′‐dipeptides using a single nitrogen atom as a linchpin.     

Asymmetric radical cyclization of (2S,3S)-2,3-butanediyl, (2S,4S)-2,4-pentanediyl,and (2S,5S)-2,5-hexanediyl bis(4-vinylbenzoate)s as a model reaction for asymmetric cyclocopolymerization

The asymmetric cyclocopolymerization of bis(4-vinylbezoate) of a chiral diol with styrene is a promising method for the preparation of optically active polystyrene derivatives because of main-chain chirality. However, the mechanism for chirality induction from the chiral diol to the main chain is still unknown. To clarify the chirality induction mechanism, we carried out the radical cyclizations of (2S,3S)-2,3-butanediyl bis(4-vinylbenzoate), (2S,4S)-2,4-pentanediyl bis(4-vinylbenzoate), and (2S,5S)-2,5-hexanediyl bis(4-vinylbenzoate) with tri-n-butyltin hydride or allyltri-n-butyltin as a chain-transfer reagent as model reactions for asymmetric cyclocopolymerization. The absolute configuration was determined with single-crystal X-ray crystallography and a circular dichroism exciton chirality method. The distribution of the stereoisomer showed (R)-configuration selectivity (21–34% diastereomeric excess) in the intramolecular cyclization and an extremely low extent (<1%) of the (S,S)-cyclized product among the four stereoisomers. Therefore, chirality induction is caused by the selective inhibition of the (S,S)-racemo configuration. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 4671–4681, 2004     

Palladium‐Catalyzed Enantioselective Cacchi Reaction: Asymmetric Synthesis of Axially Chiral 2,3‐Disubstituted Indoles

We report herein the first examples of a palladium‐catalyzed enantioselective Cacchi reaction for the synthesis of indoles bearing a chiral C2‐aryl axis. In the presence of a catalytic amount of Pd(OAc)₂ and (R,R)‐QuinoxP* ligand, reaction of N‐aryl(alkyl)sulfonyl‐2‐alkynylanilides with arylboronic acids under oxygen atmosphere afforded enantioenriched 2,3‐disubstituted indoles in high yields and enantioselectivity. The indole ring is constructed de novo in this process and a complexation‐induced chirality transfer is proposed to account for the observed enantioselectivity.     

手性磷酸催化剂在不对称合成中的应用

手性磷酸是2004年报道的一类具有新型结构的强酸性Bronsted酸催化剂,近几年来的研究取得了很大的进展,已经成为有机小分子催化剂的一个重要分支。手性磷酸在催化一系列亚胺的加成和还原反应比如Mannich、亚胺的氢转移、亚胺的膦酰化、Pictet-Spengler、 Strecker、aza-Diels-Alder、 Friedel-Craft和α-重氮酯的烷基化等反应时都表现出了非常好的催化活性和立体选择性。本文主要综述了手性磷酸催化剂应用于亚胺相关反应的研究进展。     

Asymmetric Catalytic Assembly of Triple-Columned and Multilayered Chiral Folding Polymers Showing Aggregation-Induced Emission (AIE)

Unprecedented chiral multilayer folding 3D polymers have been assembled and regulated by uniform and differentiated aromatic chromophore units between naphthyl piers. Screening catalysts, catalytic systems and monomers were proven to be crucial for asymmetric catalytic Suzuki–Miyaura polycouplings for this assembly. X-ray crystallography of the corresponding dimers and trimers revealed the absolute configuration and the intermolecular packing pattern. Up to 61 960 M_w/41 900 M_n and m/z 4317 for polymers and oligomers, as confirmed by gel permeation chromatography (GPC) and MALDI-TOF MS, indicated that these frameworks were composed of multiple stacked layers. The resulting multiple π-assemblies exhibited remarkable optical properties in aggregated states (photoluminescence in solids and aggregation-induced emission in solutions), as well as reversible redox properties in electrochemical performance.     

Asymmetric Synthesis of Chiral Atropisomeric Bis‐Aryl Organophosphorus from Menthyl H‐Phosphinate

This review describes new methods for the synthesis of chiral monophosphine ligands with menthyl phenylphosphinate as a chiral auxiliary through asymmetric Suzuki‐Miyaura cross‐coupling reactions and asymmetric C–H functionalization. The chiral menthyl phenylphosphinate as a chiral auxiliary is easy to prepare and the menthyl group can easily be transformed into other functional groups, with the chiral center synchronously remaining. These methodologies provide highly efficient and practical strategies for the synthesis of novel axially chiral biaryl monophosphine oxides and their corresponding phosphines. Meanwhile, these reactions are easy to handle and exhibit wide scope for substrates with excellent diastereomeric ratios.     

手性膦配体合成及其在不对称催化中的应用*

本文较为详细地综述了手性膦配体的合成进展, 并介绍了其在不对称氢化反应、不对称氢甲酰化反应及不对称氢酯基化反应中的应用。     

含硫手性配体催化的有机锌试剂在不对称加成反应中的最新研究进展

按配位原子的数目和种类进行分类, 综述了近年来含硫的手性配体在有机锌试剂和醛等化合物的不对称加成反应中的最新研究进展.     

手性铝催化剂在不对称合成中的应用

综述了手性铝催化剂在不对称Diels-Alder、Michael加成、1, 3-偶极环加成、Ene反应、磷氢化、氰硅化、烯丙基化、氢化、Claisen重排、Friedel-Crafts烷基化、Aldol等反应中的应用.     

新型手性稀土配合物的合成、表征及其在不对称催化反应中的应用

作为符合绿色化学标准的稀土三氟甲磺酸盐Ln(OTf)3化合物打破了传统路易斯酸催化的模式，以其在水中稳定、催化用量少(一般少于10 mol％)和可回收再用的独特性质而受到广泛关注。Ln(OTf)3化合物可以催化许多有机合成反应，得到多种多样重要的合成中间体。但是，到目前为止，手性