手性配体催化二烷基锌—羰基不对称加成制光活性醇的反应

关于手性配体催化二烷基锌一羰基的不对称加成生成光活性醇的反应,从催化剂、不对称催化机理与自催化过程、手性放大等方面进行了概述,参考文献50篇。     

Efficient Preparation of Biologically Important 1,2-Amino Alcohols

An efficient three-step methodology developed for the preparation of 1,2-amino alcohols. In the first step a rapid coupling between bromoketones and potassium phthalimide in ionic liquid produced α-phthalimido ketones in quantitative yields, which is followed by a facile reduction using NaCNBH₃ in acetic acid to give corresponding phthalimido alcohols and finally effecting hydrazinolysis in water at 60 °C to yield biologically important 1,2-amino alcohols.     

Catalytic Enantioselective Addition of Nitro Compounds to Imines-A Simple Approach for the Synthesis of Optically Active beta-Nitro-alpha-Amino Esters

No AbstractSupporting information for this article is available on the WWW under http://www.angewandte.com or from the author.     

Straightforward Synthesis of 1,2-Amino Phosphate Diesters and Application to the Synthesis of Novel 1,2-Amino Ether Diesters

A variety of 1,2-amino alcohol diesters 1 reacted smoothly with diethyl chlorophosphate under basic conditions to afford the corresponding 1,2-amino phosphate diesters 2 in excellent yields. These compounds served as useful precursors for subsequent nucleophilic attack by alcohols in an S_N2 fashion to provide 1,2-amino ether diesters 3.     

Synthesis of Optically Active Isothiazole Derivatives from L-(α)-Amino Acids

Summary. Several enantiomerically pure 3,5-disubstituted isothiazol-5-ylideneamine hydrobromides were prepared by oxidation of chiral 3-amino-2,3-unsaturated thioamides. The starting thioamides derived from natural L-α-amino acids represent a novel group of synthetically useful chiral reactants.     

光学活性有机钛试剂与苯甲醛不对称加成反应

光学活性二醇（１Ｒ，２Ｒ）－（＋）－１，２－二苯基－１，２－乙二醇（Ⅲａ）和（２Ｒ，３Ｒ）－（－）－１，１，４，４－四苯基－２，３－（缩丙酮）－１，４－丁二醇（Ⅲｂ）分别修饰Ｔｉ（ＯＰｒｉ）３Ｃｌ，再与甲基锂和乙基锂进行烷基化，制备出新的手性有机钛试剂Ⅱａ和Ⅱｂ，然后与苯甲醛进行加成，所得１－苯基乙醇（Ⅳａ）和１－苯基丙醇（Ⅳｂ）的光学收率分别为２５～６５％ｅ．ｅ．和１０～２０％ｅ．ｅ．。简单讨论了Ｃ２－对称型二醇对立体选择性及反应条件的影响     

Simple and Mild Syntheses of Optically Active 2-（N,N-Dialkylamino）oxazolines

Chloroamidinium salts and α-amino alcohols derived from commercially available tetraalkyl ureas and α-amino acids, respectively, can be used for the syntheses of optically active 2-(N,N-dialkylamino)oxazolines in moderate to excellent yields without any catalyst. It is a simple and mild method for the syntheses of optically active oxazolines     

Ruthenium-Catalyzed Deaminative Hydrogenation of Amino Nitriles: Direct Access to 1,2-Amino Alcohols

A new approach for the efficient and highly selective synthesis of 1,2-amino alcohols by direct reductive hydrolysis of N-formyl-protected α-amino nitriles is reported. The commercially available RuHCl(CO)(PPh₃)₃ complex was found to be a suitable catalyst for this operationally simple protocol, in which no stoichiometric amounts of undesired metal waste are generated. The deaminative hydrogenation is performed at 55 bar of H₂, using a 6:1 mixture of 1,4-dioxane/water as solvent. In addition, hydroxymethyl alcohols were prepared from cyanoketones under very similar conditions.     

Highly Enantioselective Synthesis of Linear β-Amino Alcohols

β-Amino alcohols derived from α-amino acids have been extensively used as a powerful source of chirality. Transforming the alcohol moiety into a good leaving group has allowed the rearrangement of these β-amino alcohols and the introduction of a large number of nucleophiles through the anchimeric participation of the nitrogen atom. An overview on the recent progress realized on the rearrangement of these β-amino alcohols in the presence of (CF₃CO)₂O and H₂SO₄ is reported.     

Improved Synthesis of Cyclic Tertiary Allylic Alcohols by Asymmetric 1,2‐Addition of AlMe3 to Enones

The development of an improved protocol for the enantioselective Rh^I/binap‐catalysed 1,2‐addition of AlMe₃ to cyclic enones is reported. ³¹P NMR analysis of the reaction revealed that the catalyst in its resting state is a chloride‐bridged dimer. This insight led to the use of AgBF₄ as an additive for in situ activation of the dimeric precatalyst. Thus, the catalyst loading can now be reduced to only 1 mol % with respect to rhodium. Various 5–7‐membered cyclic enones can be transformed into tertiary allylic alcohols with excellent levels of enantioselectivity and high yields. The obtained products are versatile synthetic building blocks, shown by a highly enantioselective formal total synthesis of the pheromone (?)‐frontalin as well as formation of a bicyclic lactone that has the core structure of the natural flavour component “wine lactone”.     

用Sharpless不对称双羟化反应合成手性β-氨基醇

以烯烃为原料合成了一组对映体纯的β-氨基醇．在手性配体1,4-双(9-O-奎宁)-2,3-二氮杂萘[(QN)₂PHAL]存在下, 通过烯烃的Sharpless不对称双羟化、环化、亲核开环和催化氢化等步骤方便地合成了手性β-氨基醇. 从环氧化物到氨基醇的总产率为89%～94%, β-叠氮醇和β-氨基醇的光学纯度高达90%～99% ee. 同时考察了影响环氧化物开环的各种因素．     

手征性杂氮钛三环化合物的合成

杂氮钛三环(titatrane)(Ⅰ)是一类具有五配体特殊结构的杂环化合物,由于对其合成工作研究的不多,所以这类化合物的一些性质还鲜为人知。我们对杂氮钛三环的合成方法做了改进,将手性中心引入到这类化合物中,合成了下列结构图中(Ⅱ)所示的具有手性的杂氮钛三环。     

旋光性高分子的合成（下）

旋光性高分子的合成（下）刘引烽，华家栋（上海科技大学化学系，上海，２０１８００）４不对称聚合由外消旋手性单体制备旋光性高分子必须通过选择性聚合才能实现。选择性聚合是指外消旋的两个对映异构单体进行聚合时，由于体系中存在着某种不对称的诱导因素，其中之一比...     

Simple Synthesis of Versatile Coumarin Scaffolds

We describe an approach using ring‐closing metathesis (RCM) to synthesize versatile coumarin derivatives that present appropriate substitutions both at the aromatic and at the α,β‐unsaturated lactone ring. The obtained compounds can be used as molecular scaffolds suitable for further diversifications through a combinatorial approach.     

Asymmetric Grignard Synthesis of Tertiary Alcohols through Rational Ligand Design

A simple, general and practical method is reported for highly enantioselective construction of tertiary alcohols through the direct addition of organomagnesium reagents to ketones. Discovered by rational ligand design based on a mechanistic hypothesis, it has an unprecedented broad scope. It utilizes a new type of chiral tridentate diamine/phenol ligand that is easily removed from the reaction mixture. It is exemplified by application to a formal asymmetric synthesis (>95:5 d.r.) of vitamin E.