铑(Ⅰ)催化的不对称硅氢化反应合成手性2-氨基-1-芳基乙醇研究

报道了以Rh(I)－手性2－（2－吡啶基）－4－羧甲基－1，3－噻唑烷为催化剂，2－氨基芳香酮的不对称硅氢化反应，在常温常压下手性2－氨基－1－芳基乙醇的产率几乎可达定量，产品光学纯度可达80％e.e以上。     

手性亚磺酰胺催化不对称硅氢化合成手性β-氨基膦酸酯(英文)

以手性亚磺酰胺作为催化剂,三氯硅烷为还原剂,发展了通过有机小分子催化合成有用的手性β-氨基膦酸酯的方法,获得了较好的产率和对映选择性。     

RuPHOX-Ru催化的手性γ-氨基醇的不对称氢化合成

研究了双反应活性中心手性二茂钌催化剂RuPHOX-Ru催化的一系列潜手性β-酰亚胺酮的不对称氢化反应.在优化的反应条件下(无水Na2CO3为碱,乙醇为溶剂),几乎所有的反应都可定量地转化为相应的手性γ-酰亚胺醇产物,且产物的对映选择性最高可达98%ee.产物的结构进行了充分的表征,且绝对构型也得到了确认.报道的β-酰亚胺酮的不对称氢化反应不仅简洁高效,且产物可通过简单的转化得到一系列手性γ-伯胺醇.     

手性磷酰胺类化合物不对称催化合成α-芳基丙醇类化合物

对一系列磷酰胺类化合物进行了考察,发现以芳香醛类化合物与二乙基锌作为底物,手性磷酰胺类化合物4a(N-(1R,2R)-2-(异丙基氨基)-1,2-二苯基乙基)-P,P-二苯基次膦酰胺)作为催化剂,通过发生不对称还原反应合成具有生理活性的α-芳基丙醇类化合物.手性磷酰胺类化合物合成所使用的起始物料不仅廉价易得,而且催化效...     

噻唑烷类手性配体在催化不对称硅氢化反应中的应用

合成了7种手性噻唑烷配体络铑(Ⅰ)络合物催化剂并考察了它们对苯乙酮不对称硅氢化反应的催化性能.研究发现由L-半胱氨酸或其酯制备的取代噻唑烷类手性配体新生成的C_2手性中心的构型对催化不称硅氢化反应的最终结果几乎没有影响,并且首次以定量的结果报道了造成了这一现象的直接原因:在铑(Ⅰ)络合物[Rh(COD)Cl])2催化作用下手性噻唑烷配体的C_2手性中心发生了快速外消旋化反应.     

手性噻唑烷-铑(I)配合物催化的苯乙酮不对称硅氢化反应

由L-半胱氨酸甲酯与α-吡啶甲醛缩合制备了2-(α-吡啶基)-4-羧甲基-1, 3-噻唑烷手性配体。用该手性配体与[Rh(COD)]2反应原位生成的Rh(I)配合物为催化剂进行了苯乙酮的不对称硅氢化反应。反应的化学产率达91%, 光学产率达82.1%e.e.。考察了各种反应条件对催化剂性能的影响。     

手性噻唑烷-铑(I)配合物催化的苯乙酮不对称硅氢化反应

由L-半胱氨酸甲酯与α-吡啶甲醛缩合制备了2-(α-吡啶基)-4-羧甲基-1, 3-噻唑烷手性配体。用该手性配体与[Rh(COD)]2反应原位生成的Rh(I)配合物为催化剂进行了苯乙酮的不对称硅氢化反应。反应的化学产率达91%, 光学产率达82.1%e.e.。考察了各种反应条件对催化剂性能的影响。     

手性金属配合物催化的前手性羰基化合物的不对称硅氢化反应研究进展

评述了近年来手性金属配合物催化的前手性羰基化合物的不对称硅氢化反应研究进展。     

不对称催化合成手性α-氨基酮

“对映异构”是有机化学中的基本概念,也是本科有机化学教学中的重点和难点内容。现有有机化学实验教材中关于对映体合成的实验极其有限,通过不对称催化来实现对映体合成的教学案例尤其少见。本文拟将文献报道的手性布朗斯特酸催化合成α-氨基酮的三组分不对称还原胺化反应开发为教学实验,通过同小组学生使用手性构型不同、取代基不同的催化剂来催化该反应,探究催化剂结构对对映选择性控制结果的影响,并引入核磁共振、比旋光度测定、手性高效液相色谱等分析技术,应用于所合成的手性化合物的结构鉴定、构型判断和对映体过量的测定。这是将现在常规的两组分、非手性合成教学实验升级到多组分、手性合成教学实验的新举措。结果表明,该实验重复性好、时长合适,同时兼具复杂性、探究性和创新性。它的实施有利于学生学习复杂化学反应操作、理解复杂化学反应历程、分析立体选择性控制影响因素以及培养学生进行创新性实验研究的能力。     

不对称氢化法合成手性β－位芳基取代异丙胺

手性胺是有机合成中一种很重要的中间体,对β－位芳基取代的烯酰胺的不对称氢化可以得到手性β－位芳基取代的异丙胺,该手性异丙胺是安非他命、司米吉兰、福莫特罗和坦索罗辛等手性药物的前体．随着手性配体的发展,对α－位芳基取代的烯酰胺的不对称氢化取得了很好的对映选择性,但是,对β－位芳基取代的烯酰胺的不对称氢化却没有获得〉50％的对映选择性．     

Chiral Alkoxy Side Chains from (-)-Amino Acids in Mediating Asymmetric Synthesis of Tricarbonyl(cyclohexadienyl)iron Complexes

The asymmetric induction in the complexation reaction of (S)-1-methyl-2-(5-methyl-cyclohexa-1,4-dienylmethyloxy)-pyrrolidine 5 and (S)-2-(2-N,N-dimethylamino-1-propanoxy)-5-methylcyclohexa-1,4-diene 6 having heteroatom adjacent the stereogenic center has been investigated. The diastereoselectivity was determined directly from the diastereotopic peaks in the ¹H NMR or by chemical correlation with 9 . The conversion of η-1,4-complexes 7a and 8a to 9 proceeded with high retention of configuration while that of the η-2,5-Fe(CO)₃ complexes 7b and 8b undergoes considerable racemization.     

Rh(I)-Catalyzed Asymmetric Hydrosilylation and Hydroboration/Oxidation Reactions Using Berens Ligand

The Berens ligand 2 was used in a number of Rh(I)-catalyzed asymmetric hydrosilylations of acetophenones under standard conditions, affording the corresponding 1-arylalcohols in ees up to 65%. Some novel Rh catalysts were generated in situ from the neutral precatalyst [Rh(µ-Cl)(COD)]₂ and screened in the catalytic asymmetric hydroboration/oxidation of styrenes, gave enantioselectivities of up to 62%.     

Asymmetric Synthesis of Novel Vicinal Amino Alcohols via Intramolecular Ketone-N-sulfinylimine Pinacol-Type Reductive Coupling Promoted by SmI2

A novel intramolecular asymmetric ketone-N-sulfinylimine pinacol-type reductive coupling reaction induced by SmI₂ was reported. A series of 1-amino-1,2,3,4-tetrahydronaphthalen-2-carbinols were obtained in moderate to good yields with excellent ee and high dr.

[Supplementary materials are available for this article. Go to the publisher's online edition of Synthetic Communications® for the following free supplemental resource(s): Full experimental and spectral details.]     

Convenient Asymmetric Borane Reduction of Ketones Catalyzed by Simple Amino Alcohols and Corresponding Amino Acids

The catalytic enantioselective borane reduction of ketones is a well-studied theme1. Since the pioneering work of Corey2, a variety of good catalysts have been synthesized through further modification on simple amino alcohols and their corresponding amino acids,3,4 . But when simple amino alcohols were directly used in the reduction their catalytic efficiency was very low. For the first time Buono5 has reported through carefully chosen reaction condition the catalytic efficiency of a simple…     

Synthesis of 1,3‐Amino Alcohols by Hydroxy‐Directed Aziridination and Aziridine Hydrosilylation

We describe an approach to N‐tosyl 1,3‐amino alcohols that consists of a diastereoselective aziridination reaction of acyclic allylic alcohols and an unprecedented regioselective hydrosilylation of α‐hydroxy aziridines. The products contain up to three contiguous stereocenters. Computational studies outline key aspects of the aziridination mechanism, which is different and more intricate than anticipated.     

N-方酰麻黄碱配体的合成及催化前手性芳酮的不对称还原反应

方酸与醇反应成方酸二酯,后者与天然麻黄碱反应得到N-方酰麻黄碱或N-方酰双麻黄碱。单N-方酰麻黄碱与脂肪胺及硫氢化钠等反应合成了C-3位含氮和含硫的系列配体。首次将这些方酰麻黄碱配体经原位制备手性恶唑硼烷催化前手性芳酮及二酮的不对称还原反应,得到化学产率和e.e.值分别为85%-98%和52.5%-87.4%的手性仲醇。新化合物的结构已IR,^1H NMR,MS和元素分析所证实,化合物4b的晶体结构用X射线射确认。     

偕双硅取代的手性α-氨基酸和β-氨基醇的不对称合成

以3,3-偕双硅醛和(S)-叔丁基亚磺酰胺为原料,经7步反应,以20.2%和29.5%的收率合成了偕双硅α-氨基酸(12)和偕双硅β-氨基醇(14)。其中,14可进一步以50%的收率转化为相应的手性单噁唑啉配体(15),产物结构经¹H NMR, ¹³C NMR和HR-MS(ESI)表征,绝对构型经XRD确证,光学纯度由HPLC手性OD柱测定。      

Iron‐ and Cobalt‐Catalyzed Asymmetric Hydrosilylation of Ketones and Enones with Bis(oxazolinylphenyl)amine Ligands

Chiral bis(oxazolinylphenyl)amines proved to be efficient auxiliary ligands for iron and cobalt catalysts with high activity for asymmetric hydrosilylation of ketones and asymmetric conjugate hydrosilylation of enones.     

Chemoenzymatic Synthesis of Enantiopure Amino Alcohols from Simple Methyl Ketones

This study highlights the straight-forward synthesis of substituted 1,2-amino alcohols from simple and readily available aromatic methyl ketones. Starting from acetophenone derivatives, the straight-forward synthesis strategy involved an initial bromination of the alpha-positioned methyl group in the first step, followed by a simple hydrolysis to the hydroxyketone (2-hydroxyacetophenone). The hydroxylated intermediate was subsequently converted from Silicibacter pomeroyi to the final 1,2-amino alcohol by using the transaminase. The transaminase-catalyzed reaction proceeded with yields up to 62 % and always excellent enantiomeric excess of >99 %. Interestingly, the keto-enol-tautomerism of the hydroxyl ketone yields an unexpected amino alcohol isomer.