手性氨基醇催化的前手性芳酮的不对称还原反应

首次以天然D-樟脑的衍生物为原料, 合成了两个新型龙脑基氨基醇配体, 研究了它们与硼烷原位制备成手性噁唑硼烷后, 在不对称催化氢化还原前手性芳酮中的性能, 得到的手性仲醇的对映体过量(ee)值最高可达96%, 还考察了反应温度、时间、溶剂等因素对苯乙酮的不对称氢化还原的化学产率和光学收率的影响.     

Catalytic Enantioselective Reduction of Prochiral Ketones with Chiral Ferrocenyl Amino Alcohols

The asymmetric reduction of prochiral ketones was catalyzed by a class of recoverable and highly stable chiral ferrocenyl amino alcohols derived from natural amino acids to yield optically active secondary alcohols in high chemical yields and moderate to good enantiomeric excesses.     

雪松胺醇-硼烷络合物催化的潜手性酮的不对称还原反应

雪松胺醇-硼烷络合物催化的潜手性酮的不对称还原反应     

含流手性β-氨基醇的合成及其在对映选择性还原反应中的应用

S烷基-L-半胱氨酸2a～2c通过酯化、格林亚反应合成了光学活性含硫β-氨基 醇4a-4c，并用于潜手性酮的对映选择性NaBH_4／12还原．光学活性二级醇化学产 率很高，对映体过量最高可达93％．     

含硫手性β-氨基醇的合成及其在对映选择性还原反应中的应用

S-烷基-L-半胱氨酸2a～2c通过酯化、格林亚反应合成了光学活性含硫β-氨基醇4a～4c,并用于潜手性酮的对映选择性NaBH4/I2还原.光学活性二级醇化学产率很高,对映体过量最高可达93%.     

Synthesis of N-Squaramidoacids and Their Application in Asymmetric Borane Reduction of Prochiral Ketones

A series of novel N-squaramidoacid ligands were prepared conveniently. Without converting to corresponding amino alcohols, these ligands could be used in asymmetric borane reduction of prochiral aromatic ketones to give secondary alcohols in good to excellent enantiomeric excesses. The results showed that N-squaramidoacids are more efficient ligands than N-sulfonyl amino acids. N-Squaryl proline was proved to be an excellent ligand in this catalytic asymmetric process.     

手性噁唑硼烷催化的烷基(4-二烷基氨基)苯基酮的不对称硼烷还原

在手性硼杂噁唑烷催化下，用硼烷不对称还原了一系列烷基4-二烷基氨基苯基酮，结果表明由于存在催化剂和硼烷中的硼原子与氮原子的强络合作用，在该不对称还原中，该类酮比相应的烷基4-烷基、4-烷氧基、4-烷硫基酮表现出了较明显的取代基对对映选择性的影响。     

不对称硼烷还原合成手性氨基醇

用原位生成的手性噁唑硼烷为催化剂,用2molBH3对1molα 或β 氨基酮进行了对映选择性还原,生成光学活性氨基醇 硼烷络合物,后者脱去BH3后给出光学活性氨基醇,ee值最高达99%.讨论了氨基酮结构与反应选择性的关系.     

手性噁唑硼烷结构与还原苯基乙基甲酮的对映选择性研究~≠

本文以苯基乙基甲酮为还原底物,研究了原地(in situ)制备的在3、4、5位具有不同取代基的手性1,3,2-(口恶)唑硼烷催化剂的结构与不对称催化效应关系。研究结果表明,在不对称催化硼烷还原反应中(CBS方法),产物的构型和对映选择性主要受手性(口恶)唑硼烷的4位取代基控制。     

Enantioselective Reduction of Prochiral Ketones with NaBH4/Me2SO4/(S)-Me-CBS

The enantioselective reduction of prochiral ketones with NaBH₄/Me₂SO₄/(S)-Me-CBS is described. Borane is generated in situ via the reaction of NaBH₄ with Me₂SO₄ in tetrahydrofuran, which is as efficient as the commercial one. Such in situ–generated borane reagent was applied to reduce prochiral ketones in the presence of chiral oxazaborolidine catalyst directly. The corresponding chiral secondary alcohols were obtained with excellent enantiomeric excesses (93–99% ee) and good to excellent yield (80–99%).     

奎宁与钴（Ⅱ）手性络合物用于前手性酮的不对称催化还原

奎宁与钴（Ⅱ）手性络合物用于前手性酮的不对称催化还原刘湘＊李纪国张正（无锡轻工大学化工系无锡２１４０３６）（南京大学化学系南京）关键词手性络合物，不对称还原，前手性芳香酮１９９６－１０－２５收稿，１９９７－０４－２２修回前手性酮的不对称催化还原作为光...     

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。     

Catalytic Enantioselective Reduction of Ketones by a Chiral Gallium Complex and Catecholborane

A catalytically active version of Noyori's famous BINAL reagent Li[AlH(OEt)(BINOL dianion)] is formed by the combination of LiGaH₄, monothiobinaphthol (MTB), and catecholborane. With this mixture unsymmetrical ketones can be reduced in high enantioselectively. Un=unsaturated unit; R=alkyl.     

Asymmetric Reduction of Prochiral Ketones in Aqueous Micelles of Chiral Surfactants (-)-Trialkylmskthylammcnium Bromides

Prochiral Ketones were reduced by NaBH₄ in aqueous micelles formed from chiral surfactants (-)-N-alkyl-N,N-dimethylmenthylammonium bromides, giving optically active alcohols with enantioselectivity up to 17.7%.     

Amino Acid Mediated Borane Reduction of Ketones IIa

Summary.  Acetophenone, 2,2-dimethylcyclopentanone, 3,3-dimethyl-2-butanone, 3-methyl-2-butanone, and 2-pentanone were reduced with borane mediated by (S)-alanine, (S)-methionine, (S)-leucine, (S)-valine, and (S)-isoleucine in very good yields giving predominantly alcohols of (R)-configuration (ee = 23–89%). A molecular topology based model was developed for describing the influence of the substituents, both in the oxazaborolidine type reagent and in the ketone, on the observed chiral induction. Received May 31, 2001. Accepted June 25, 2001     

Synthesis of Novel Chiral Ionic Liquid and Its Application in Reduction of Prochiral Ketones to the Corresponding Chiral Alcohols Using NaBH4

A novel chiral ionic liquid (CIL) based on nicotinium salt has been synthesized and used as an efficient asymmetric chiral catalyst for reduction of acetophenone derivatives with NaBH₄ in methanol at room temperature. The optically active alcohols were obtained in low to moderate enantiomeric excess in a short reaction time.     

Asymmetric Transfer Hydrogenation of Prochiral Ketones in Aqueous Media with New Water-Soluble Chiral Vicinal Diamine as Ligand

As a consequence of the increasing demand for atom economy and environmental friendly methods, the water soluble ligands and their metal complexes are of great interest in catalytic synthesis because of simpler product sepa ration and the possibility of recycling. [1] Unique reactivity and selectivity are often observed in aqueous reactions. [2]Recently, we have developed a new water-soluble chiral vicinal diamine and synthesized its mono-N-tosylated derivative for the first time. The application of its mono-N-tosylated derivative in catalytic asymmetric transfer hydrogenation of prochiral ketones was examined in aqueous media. High activity (up to ＞ 99 % conv. ) and good enatioselectivity ( up to 98% ee ) were achieved for most of prochiral aromatic ketones in organic solvent free system. [3]     

A Facile Enantioselective Reduction of Acetylferrocene with Chiral Sodium Hydroboro—L—prolinate

IntroductionChiral ferrocene and their derivatives have at-tracted much attention of some researchers workingin the fields of asymmetric synthesis and nonlinearoptical material. In asymmetric catalysis,chiralferrocenyl phosphine and ferrocenyl amine are ex-cellent chiral ligands in the asymmetric hydrogena-tion,asymmetric allylic substration,asymmetricaldol reaction and asymmetric Michael additionetc.[1— 6] . While the starting material used to syn-thesize the chiral ferrocene is optically ac…