4-取代-脯氨醇催化的前手性酮不对称硼烷还原

(2S)-(二苯基羟甲基)-(4S)-苯氧基-四氢吡咯(10)由羟脯氨酸(6)经4步反应制得。用10催化6种前手性酮的不对称硼烷还原反应,其结果与(S)-二苯基脯氨醇催化的同一反应的结果进行了对比。     

金属配合物/手性磷酸参与的不对称接力催化反应

金属配合物和有机小分子双体系联合催化的不对称接力催化反应是一新兴热点研究领域. 接力催化可以由易得的起始原料生成结构复杂的化合物, 实现单一催化剂无法实现的新反应, 并且避免了对不稳定中间体的分离纯化, 提高了反应的步骤经济性和原子经济性. 手性磷酸是近年来研究最为热门的有机小分子催化剂之一, 其与金属催化剂结合催化也得到了深入的研究. 本工作即针对金属催化剂和手性磷酸结合的接力催化反应的研究进展, 做一简要评述.     

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。     

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。     

New Trends in Asymmetric Phase Transfer Catalysis

Phase Transfer Catalysis (PTC) is a powerful tool to perform reactions in a practical fashion, both in laboratory and industrial scale. Significant cost savings and major process improvements can be achieved in reactions performed under PTC conditions. In the last few years remarkable results in stereoselective reactions were achieved using chiral, non-racemic quaternary ammonium salts. Moreover, the use of bulky, chiral phosphate anions paired with achiral cations to generate lipophilic ion pairs allowed to design new avenues for the stereoselective construction of important building blocks. Hydrogen bond interactions were also shown to provide new pathways for asymmetric nucleophilic substitutions using insoluble reagents under PTC conditions. This Review will focus on recent advances in developing practical synthetic routes to construct molecules in a stereoselective fashion under PTC conditions.     

手性方酸衍生物的合成及在前手性酮的不对称催化还原反应中的应用研究进展

本文评述手性方酸衍生物的研究进展，包括多个系列的新型手性方酰化氨基醇及氨基酸配体的设计合成以及它们在前手性单酮和二酮的不对称催化还原反应中的应用。     

钯配合物和手性磷酸连续催化的烯丙醇和醛的不对称羰基烯丙基化反应

利用钯配合物/手性磷酸催化剂体系,通过不对称连续催化,实现了烯丙醇和醛的不对称羰基烯丙基化反应.该反应使用廉价易得的烯丙醇底物,在催化量的手性磷酸作用下,以优秀的产率和立体选择性得到了高烯丙醇产物.     

Catalytic asymmetric borane reduction of prochiral ketones using chiral camphor-derived mercapto-alcohols

Easily available D-(+)-camphor-derived chiral mercapto-alcohols 2 and 3 were employed for catalytic asymmetric borane reduction of aromatic ketones. Moderate enantioselectivities with e.e. 20.2-72.1% were obtained with 10 mol% catalyst. Opposite asymmetric induction was achieved when mercapto-alcohols 2 and 3 were used.     

Asymmetric reduction of ketones with sodium aluminum hydride modified with chiral amino alcohols

Asymmetric reduction of ketones with hydride complexes, which were prepared by in situ modification of NaAlH₄, with various chiral amino alcohols or diamines, was studied. The highest enantioselectivity (up to 93% ee) was achieved using 2-(hydroxydiphenylmethyl)pyrrolidine as a chiral inducing agent.     

Enantioselective metal-free reduction of ketones by a user-friendly silane with a reusable chiral additive

1-Hydrosilatrane, a safe and easy-to-handle reducing reagent that can be inexpensively accessed, has been shown to reduce prochiral ketones asymmetrically in the presence of chiral 1,2-aminoalcohols with ees ranging from 8% to 86%. The best result was achieved using ephedrine as the source of chirality, which is readily commercially available. The additive can be recovered through extraction and reused without any erosion of enantioselectivity.     

New and efficient catalysts for enantioselective borohydride reduction of ketones and imines

Optically active aldiminato cobalt(II) complexes have been found to catalyze the enantioselective reduction of ketones with sodium borohydride affording the corresponding optically active secondary alcohols in high chemical yields with high enantioselectivities. The enantioselective borohydride reduction is also applicable to not only C=O bonds in aromatic ketones but also to C=N bonds in aromatic imines.     

Chiral Borated Esters in Asymmetric Synthesis： 1. The First Asymmetric Reaction Catalyzed by Chiral Spiroborated Esters with an O3BN Framework

The first asymmetric reaction catalyzed by chiral spiroborated esters with an O3BN framework was reported. In the presence of 0.1 equivalent of (R,S)-1 or (S,S)-1, acetophenone was reduced by 0.6 equivalent of borane in THF at 0-5℃ for 2 h to give (R)-1-phenylethanol of up to 76% ee and 73% isolated yield. Influence of reaction conditions on the stereoselectivity of the reduction was investigated and a possible catalytic mechanism of the chiral spiroborated esters toward the reduction was also suggested.     

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.     

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...