Synthesis of new chiral 1,2,3,4-tetrahydroisoquinoline β-amino alcohols from L-DOPA

Four new chiral 1,2,3,4-tetrahydroisoquinoline-derived β-amino alcohols were synthesized from L-DOPA in good yields. The structures of the target compounds were confirmed by ^1H NMR, ^13C NMR and MS.

Synthesis of a New Chiral Cyclicβ-Amino Alcohol

A new chiral cyclic β-amino alcohol (R)- 1 -(l '-amino-2'-naphthylethyl)-cyclopentanol2, which had notbeen reported previously, was prepared from (R) - 3 - (2 - naphthy1 )- alanine 3.

A Convenient Method for the Synthesis of Chiral N-Protected 1,2-Amino Alcohols via the Reduction of the Aminoketones

A series of optically active N-protected 1,2-amino alcohols were synthesized via the reduction of the corresponding a-aminoketones starting from the readily available L-amino acids.

Synthesis of new chiral 1,2,3,4-tertrahydroisoquinoline β-amino alcohol for asymmetric diethylzinc addition to aryl aldehydes(Ⅰ)

Four new chiral 1,2,3,4-tetrahydroisoquinoline-derived G-amino alcohols were synthesized from commercially available LDOPA. These ligands were evaluated in the asymmetric addition of diethylzinc to benzaldehydes and showed different catalytic activities （up to 86% ee）. The solvent played an important role in the enantioselective process. The transition state models were proposed to explain the reversion of the product configuration.

Production of Chiral Aromatic Alcohol by Asymmetric Reduction with Vegetable Catalyst

Chiral aromatic alcohols are the key chiral building block for many important enantiopure pharmaceu-ticals. In this work,we studied asymmetric reduction of prochiral aromatic ketone to produce the corresponding chiral alcohol using vegetables as the biocatalyst. Acetophenone was chosen as the model substrate. The results in-dicate that acetophenone can be reduced to the corresponding chiral alcohols with high enantioselectivity by the chosen vegetables,i.e. apple(Malus pumila),carrot(Daucus carota),cucumber(Cucumis sativus),onion(Allium cepa),potato(Soanum tuberosum),radish(Raphanus sativus),and sweet potato(Ipomoea batatas) . In the reaction,R-1-phenylethanol is produced with apple,sweet potato and potato as the catalyst,while S-1-phenylethanol is the product with the other vegetables as the catalyst. In term of the enantioselectivity and reaction yield,carrot(D. ca-rota) is the best catalyst for this reaction. Furthermore,the reaction characteristics were studied in detail using car-rot(D. carota) as the biocatalyst. The effects of various factors on the reaction were investigated and the optimal reaction conditions were determined. Under the optimal reaction conditions(reaction time 50 h,substrate concen-tration 20 mmol·L-1,reaction temperature 35 °C and pH 7),95% of e.e.(to S-1-phenylethanol) and 85% chemical yield can be obtained. This work extends the biocatalyst for the asymmetric reduction reaction of prochiral aromatic ketones,and provides a novel potential route to produce enantiopure aromatic alcohols.

Highly Regio-Selective Synthesis of β-Amino Alcohol by Reaction with Aniline and Propylene Carbonate in Self Solvent System over Large Pore Zeolite Catalyst

The nucleophilic ring opening of epoxides with amines is a well known route for the synthesis of β-amino alcohols. The use of carbonates offers significant advantages over epoxides as they are far less hazardous materials, safe for handling, do not require high-pressure equipment and most notably the possibility of solvent less reactions. In this work, utilization of zeolite as host catalyst in the reaction media for synthesis of β-amino alcohols without using solvent is reported.

A Chiral Phosphorous Derivatizing Agent for the Determination of the Enantiomeric Excess of Chiral Alcohols, Amines by ^(31)P NMR

A chiral phosphorous derivatizing agent prepared from PCl3 and (S)-BINOL was described. It is used to determine the enantiomeric excess of chiral alcohols and amines by 31P NMR.

Enantioselective Synthesis of Chiral 1-Ferrocenyl Alcohol via CBS-Reduction

Reduction of prochiral ferrocenyl ketones 2a-e in the presence of 10 mol% of chiral beta -amino alcohols 4a-b provides 1-ferrocenyl alcohols 1a-e in high yields (> 85%) with high optically purity (e.e. up to 96%).

Enantioselective addition of diethylzinc to aryl aldehydes catalyzed by 1,2,3,4-tetrahydroisoquinoline β-amino alcohol

A highly effective,new chiral 1,2,3,4-tetrahydroisoquinoline catalyst 1 for the diethylzinc addition to aryl aldehydes has been investigated.Using 10 mol%of this chiral catalyst,secondary alcohols can be obtained in up to 87%yield and 99.5%ee under mild conditions.

The Ability of Edible Mushrooms to Act as Biocatalysts: Preparation of Chiral Alcohols Using Basidiomycete Strains

To examine the potential ability of edible mushrooms to act as biocatalysts, 19 basidiomycete strains were screened. Modified media (PG, O, and PGO medium) for liquid cultivation of these basidiomycete strains were designed and tested. Wet cells (>10 g) of 4 basidiomycete strains (Pleurotus salmoneostramineus H7, P. salmoneostramineus H13, Ganoderma lucidum NBRC31863, Flammulina velutipes NBRC31862) were harvested from PGO medium for 7 days. The stereoselective reduction of α-keto esters using the 4 strains was tested. It was found that each of these strains had a reducing activity toward 6 aliphatic α-keto esters. In the presence of L-alanine as an additive, the reduction of ethyl 2-oxobutanoate and ethyl 2-oxopentanoete by P. salmoneostramineus H7 produced the corresponding alcohol with a high conversion ratio and with excellent enantiomeric excess (>99% e.e. (R)). Furthermore, ethyl pyruvate, ethyl 2-oxobutanoate, and ethyl 2-oxopentanoate were predominantly reduced to the corresponding (R)-hydroxy ester (>99% e.e.) by G. lucidum. Thus, we found that these edible mushrooms have great potential to be used as biocatalysts for the stereoselective reduction of carbonyl compounds.

Synthesis,Characterization and Structure of Chiral Amino Acids and Their Corresponding Amino Alcohols with Camphoric Backbone

Chiral amino acids and their corresponding amino alcohols bearing camphoric backbone were prepared from D-（＋）-camphoric imide and characterized by infrared, elemental analysis, ESI-MS, and NMR measurements. Among them, one intermediate （1S,3R）-3-amino-2,2,3- trimethyl cyclopentane-1-carboxylic acid hydrochloride 3 was structurally elucidated by X-ray diffraction techniques. Versatile intermolecular hydrogen bonding interactions observed in its packing structure result in a two-dimensional framework.

基于TRIZ理论的酶催化制备手性仲醇工艺改进

手性仲醇在化工制品的合成中总是被作为重要的手性中间体,其光学纯对映体的制备是手性化合物制备过程中的关键步骤。根据现有制备手性仲醇工艺中所存在的收率较低、对映体纯度不高、生产成本高等问题,运用TRIZ理论,按照发现问题、分析问题和解决问题的逻辑,对制备工艺进行优化,提出了一锅法制备手性仲醇工艺,预期有效提高收率和对映体纯度,降低生产成本。为进一步优化制备手性仲醇工艺提供了理论指导和实践参考。

Synthesis of Unprotectedα-Tertiary Amines and 1,2-Amino Alcohols from Vinyl Azides by Light Induced Denitrogenative Alkylarylation/Dialkylation

Sterically congestedα-tertiary primary amines are ubiquitous substructures in pharmaceutical and agrochemical agents yet are challenging to access.Herein,straightforward photoredox-catalyzed access to structurally diverseα,α,α-trisubstituted primary amines from denitrogenative alkylarylation or dialkylation of vinyl azides with N-hydroxyphthalimide(NHPI)esters and cyanoarenes or aryl aldehydes has been developed.The use of vinyl azide as a precursor to a primary aminewas enabled by the dual role of the Hantzsch ester to form an electron donor-acceptor complex and serve as a sacrificial reductant.This strategy provides a modular synthesis ofα-tertiary primary amines,including unprotected 1,2-amino alcohols,from simple materials with excellent functional group tolerance.The synthetic applicability of this method was demonstrated by streamlined access to 2,2-disubstituted tetrahydroquinolines.Preliminary investigations support two parallel reductive photocatalytic cycles allowing for the denitrogenative alkylarylation or dialkylation of vinyl azides via decarboxylative radical addition followed by heteroradical cross-coupling betweenα-amino radicals and aryl anion radicals or ketyl anion radicals.

Boosting chiral carboxylic acid hydrogenation by tuning metal-MO_(x)-support interaction in Pt-ReO_(x)/TiO_(2) catalysts

Engineering the surface microenvironment by tuning the binary interactions between a supported metal with a secondary metal oxide(MO_(x))or support has been a common method for improving the catalytic performance of supported metal catalysts.However,few studies have investigated the ternary interactions among the metal,MO_(x),and support.Here,we report for the first time the formation of metal-MO_(x)-support interaction(MMSI)in reducible TiO_(2)-supported PtReO_(x) catalysts,affording 87% yield and 100% ee in the tandem hydrogenation of an aqueous chiral cyclohexane-1,2-dicarboxylic acid into the corresponding diol;the catalytic activity is eight times higher than that obtained with non-reducible support counterparts in the same reaction via traditional batch synthesis with multiple steps and unfriendly reagents.Detailed experimental and computational studies suggest that the TiO_(2) crystalline phase-dependent density of the oxygen vacancies induces different Pt-ReO_(x)-TiO_(2) interactions,which dominate the electron transfer therein and tune the adsorption strength of the carbonyl moiety of the substrate/intermediate,thus promoting the hydrogenation activity and selectivity.In addition,the strong MMSI endows the optimal rutile TiO_(2) supported PtReO_(x) catalyst with an outstanding lifetime of 400 h in a fixed-bed reactor under acidic aqueous conditions and ensures efficient applications in the selective hydrogenation of aliphatic dicarboxylic acids and functional carboxylic acids.This work provides a promising strategy for the development of efficient and stable supported catalysts for the selective hydrogenation of diverse C-O and C=O bonds.

Schiff-base Amino Alcohol-zinc Complex for Enantioselective Addition of Phenylacetylene to Aromatic Ketones

A complete study of the asymmetric addition of phenylacetylene to ketones catalyzed by Schiff-base amino alcohol-Zn complex is reported in this article. The Schiff-base amino alcohols were easily prepared from amino acids in three steps. When the amount of ligand was 1%（molar fraction）, an e.e. value up to 94% was obtained. A series of practical chiral ligands were applied in the enantioselective addition of phenylacetylene to ketones without adding another stronger Lewis acid except zinc.

Chiralcel OD-H手性柱拆分醇类对映体

以Chiralcel OD-H手性商品柱在正相条件下对9种醇类对映异构体进行拆分,考察了流速、流动相中异丙醇含量、柱温等主要因素对手性拆分的影响.试验结果表明:当流动相为正己烷∶异丙醇(90∶10,v/v)、流速为0.5 mL/min、柱温为25℃、检测波长为254 nm时,8种手性醇得到分离,其中7种化合物达到基线分离,且分离度分别为R s1=12.73、R s 3=4.67、R s4=1.75、R s5=11.80、R s6=1.84、R s8=2.22、R s9=12.34,对映体在色谱固定相上的分离过程中主要受吸附焓控制.该方法快速、高效、简便,适用于手性醇类化合物的拆分.

Asymmetric hydrogenation of aromatic ketones using new chiral-bridged diphosphine/diamine-Ru(Ⅱ) complexes

A series of chiral secondary alcohols were easily prepared by means of asymmetric hydrogenation of prochiral aromatic ketones using a new（（Rax）-BuP）/（R,R）-DPEN-Ru（Ⅱ） complex catalyst system.The hydrogenation of 2-methylacetophenone in n-butanol （t-BuOK/Ru =45.6/1,S/C = 500,20 atm.of H2,20℃,48 h） afforded（S）-1-（2＇-methylphenyl）ethanol in 92%ee and〉99% conversion.

Enantiomeric Separation of Amino Alcohols by Ion-pair Chromatography

Enantiomers of four amino alcohols were resolved by ion-pair chromatography with (+)-10-camphorsulphonic acid as chiral counter ion. Studies of the influence of the mobile phase composition, the solute structure and the mobile phase flow-rate on separation are presented. Under the optimized conditions enantiomeric propanolol, norephedrine, metropolol and salbutamol were separated using dichloromethane-1-pentanol (97:3 v/v) as mobile phase on Lichrospher-100-DIOL column.

Microbial Production of Chiral Hydroxy Esters and Their Analogs: Biocatalytic Reduction of Carbonyl Compounds by Actinobacteria, <i>Agromyces</i>and <i>Gordonia</i>Strains

We screened 15 Agromyces strains from the Microbacteriaceae family and 16 Gordonia strains from the Gordoniaceae family to investigate their biocatalytic ability to reduce carbonyl compounds. Two Agromyces strains (A. soli NBRC109063 and A. humatus NBRC109085) and two Gordonia strains (G. hydrophobica NBRC16057 and G. malaquae NBRC108250) grew well in 230 medium. The stereoselective reduction of various carbonyl compounds using these four strains was investigated. We discovered that these strains can reduce aliphatic and aromatic α-keto esters and an aromatic α-keto amide. On the basis of the conversion rate and stereoselectivity of the alcohols produced, G. hydrophobica NBRC16057 is a potential biocatalyst for the stereoselective reduction of α-keto esters and an aromatic α-keto amide to the corresponding chiral alcohols. Our results also suggest that the reduction of ethyl 2-methylacetoacetate by wet G. hydrophobica NBRC16057 cells in the presence of L-glutamate is useful for the production of chiral ethyl 3-hydroxy-2-methylbutanoate.

Binol Based Chirality Conversion Reagents for Underivatized Amino Acids

Four binol based pyrrole carboxamide chiral receptors has been synthesized and effectively used as a Chirality Conversion Reagent (CCR) for underivatized amino acids. Three points of interactions take place for the conversion process. They are the reversible imine formation, the internal resonance assisted Hydrogen Bonding (RAHB) and the additional hydrogen bonds between the amino acids and the heterocylic moiety of the pendant groups. The conversion efficiency of all the receptors was found to be comparable with those of the receptors reported earlier.