苯乙酮酸薄荷醇酯的合成及其不对称Henry反应

在四乙氧基钛催化下,用天然丰产的薄荷醇为手性源与非手性苯乙酮酸乙酯进行酯交换得到含手性基团的苯乙酮酸薄荷醇酯,经手性基团的立体选择性控制让其与硝基甲烷缩合,主要得到2s-2-羟基-2-苯基-3-硝基丙酸薄荷醇酯,用IR、1H NMR、13C NMR确认了合成物结构。并用高效液相色谱法分析了诱导不对称Henry缩合反应效果。     

含平面手性和中心手性双手性因素化合物的合成及应用

[2,2]对二环苯经甲酰化、缩合、拆分得到（Rp）-4-甲酰基[2,2]对二环苯,再与L-亮氨酸的衍生物二齿手性氨基醇经缩合、还原得到由平面手性和中心手性因素构建的化合物（Rp,S）-1,1-二苯基-2-{[2,2]对二环苯基-甲氨基}-4-甲基戊醇.产物结构经IR、MS和1H NMR等进行了表征.用1H NMR考察了其作为主体对客体手性羧酸衍生物消旋体的手性识别能力.     

Co(Ⅲ)(Salen)催化的外消旋环氧化合物不对称开环

用较易得到的(R,R)-1,2-二苯基乙二胺(DPEDA)与-2-羟基-5-甲基-3-叔丁基苯甲醛缩合,得到手性Salen,再与Co络合,氧化后得到Salen型手性催化剂(R,R)-2。(R,R)-2可催化外消旋环氧化物的动力学水解拆分,所得手性二醇和手性环氧化合物对映体过量最高分别可达99%和92%。     

催化的外消旋环氧化合物不对称开环

用较易得到的(R,R)-1,2-二苯基乙二胺(DPEDA)与2-羟基-5-甲基-3-叔丁基苯甲醛缩合,得到手性Salen,再与Co络合,氧化后得到Salen型手性催化剂(R,R)-2.(R,R)-2可催化外消旋环氧化物的动力学水解拆分,所得手性二醇和手性环氧化合物对映体过量最高分别可达99%和92%.     

新型手性氨基醇的合成及其对布洛芬对映异构体的手性识别

5-叔丁基-2-二甲氨基苯甲醛与L-苯甘氨酸经酯化、格氏反应途径的产物二齿手性氨基醇经缩合、还原反应,得到新型三齿手性氨基醇(2S)-2-(5-叔丁基-2-二甲氨基)苯甲氨基-1,1,2-三苯基乙醇,运用1H NMR考察了该新型三齿手性氨基醇作为主体对客体布洛芬消旋体的手性识别能力。     

苯乙酮酸冰片酯的合成及其诱导不对称Henry反应

在四乙氧基钛催化下,用天然丰产的冰片为手性源与苯乙酮酸乙酯进行酯交换得到含手性基团的苯乙酮酸冰片酯,苯乙酮酸冰片酯在冰片基的立体控制下与硝基甲烷缩合,主要得到2R-2-羟基-2-苯基-3-硝基丙酸冰片酯,用高效液相色谱法分析了诱导不对称Henry缩合反应效果,其e.e.值为56.5%,用IR、1HNMR、13CNMR确...     

新型双烯丙基化手性二胺的合成

通过烯丙基溴化锌对手性亚胺的两次不对称加成, 合成了光活性的双烯丙基化的新型手性二胺. 首先经N-Boc保护和Dess-Martin氧化制得了光活性的(S)-N-Boc-3-苯基-2-氨基丙醛. (S)-N-Boc-3-苯基-2-氨基丙醛与(S)-缬氨基酸甲酯缩合生成手性亚胺, 在七水合三氯化铈(CeC1₃•7H₂O)催化以及底物的手性诱导作用下, 该手性亚胺与烯丙基溴化锌经不对称加成反应合成了高光活性的单烯丙基化手性胺. 该手性胺与2-噻吩甲醛缩合生成新的手性亚胺, 再次通过不对称烯丙基加成反应合成了含有四个手性中心的高光学纯的双烯丙基化手性二胺. 目标化合物和关键中间体的结构均被¹H NMR, ¹³C NMR及MS确证.     

L-亮氨酸衍生物手性氨基醇的合成与应用

以N,N-二甲基苯胺为原料,经对位溴化、邻位甲酰化得到5-溴-2-(二甲氨基)苯甲醛;L-亮氨酸经酯化、格氏反应得到二齿手性氨基醇;将5-溴-2-(二甲氨基)苯甲醛与上述氨基醇经缩合、还原得到三齿手性氨基醇;产物经红外光谱(IR)、质谱(MS)及核磁共振氢谱(1H-NMR)表征,考察了二齿手性氨基醇和三齿手性氨基醇作为...     

手性硼酸酯介入的不对称合成3(+):(R)-或(S)-1,1''-联-2-萘酚硼酸-(S)-脯氨酸酐促进的前手性亚胺的不对称硼烷还原

手性螺硼酸酯(R)-或(S)-1,1'-联-2-萘酚硼酸-(S)-脯氨酸酐[(R,S)-1或(S,S)-1]对前手性亚胺硼烷还原的不对称催化活性被观察到.在(R,S)-1或(S,S)-1存在下,由前手性二烷基酮或烷基苯酮与苯胺缩合生成的前手性亚胺在THF中被硼烷还原,高产率地给出手性仲胺,其对映体纯度高达74% ee.其中,三种手性仲胺[N-(2-戊基)苯胺,N-(3-甲基-2-丁基)苯胺和N-(4-甲基-2-戊基)苯胺]系首次合成.     

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。     

16种手性化合物在不同自制手性固定相上的拆分比较

采用高效液相色谱法,在自制的纤维素-三(3,5-二甲基苯基氨基甲酸酯)(ATEO-OD)、纤维素-三(4-甲基苯基氨基甲酸酯)(ATEO-OG)和纤维素-三(4-甲基苯基甲酸酯)(ATEO-OJ)3种手性柱上对16种不同结构的手性化合物进行了拆分和比较.试验结果表明:16个手性样品在这3种手性固定相上分别获得了不同程度的拆分,A TEO-OD对所分析样品具有更好的手性识别能力,ATEO-OG和ATEO-OJ的手性识别能力相当.     

非均匀取代淀粉衍生物手性固定相的制备及其手性识别能力

通过区域选择性方法制备了两种新型淀粉衍生物,分别为淀粉2-苯甲酸酯-3-(4-甲基苯基氨基甲酸酯)-6-(3,5-二氯苯基氨基甲酸酯)和淀粉2-苯甲酸酯-3-(3,5-二氯苯基氨基甲酸酯)-6-(4-甲基苯基氨基甲酸酯),将二者分别涂覆于氨丙基硅胶后用作液相色谱手性固定相。研究表明:所制备的手性固定相显示出特异的手性识别能力,其手性识别能力明显高于均匀取代淀粉衍生物——淀粉三(3,5-二氯苯基氨基甲酸酯),取代基的性质及在葡萄糖单元上的位置对手性固定相的手性识别能力有较大的影响。一些未在商品化的手性柱Chiralpak AD上得到有效分离的手性化合物在所制备的固定相上得到了更好的分离。所测试的8对对映体在淀粉2-苯甲酸酯-3-(4-甲基苯基氨基甲酸酯)-6-(3,5-二氯苯基氨基甲酸酯)固定相上均得到了分离,因而此固定相的手性识别能力较强,具有潜在的应用价值。     

(S)-O-acetyllactyl chloride – a versatile chiral auxiliary in stereodifferentiation of enantiomeric flavor components

The stereodifferentiation of chiral secondary alcohols, 4(5)-alkyl-substituted γ (δ)-lactones via corresponding 1, 4(1, 5)-diols, chiral 1, 3-diols, and 1-thioalkan-3-ols was carried out by diastereomeric derivatization with (S)-O-acetyllactyl chloride as a chiral auxiliary. This procedure is a convenient and reliable method for screening the enantiomeric composition of these naturally occurring flavor volatiles.     

Asymmetric synthesis of new chiral long chain alcohols

Sixteen new chiral alcohols with alkyl (C₁₁–C₁₉) and aryl, substituted aryl, hetero aryl and biaryl groups 2a–2t were synthesized by three different asymmetric reduction methods from their corresponding ketones 1a–1t. Chiral NaBH₄ (method A), chiral BH₃ (method B) and chiral AIP (method C) were used as asymmetric reduction catalysts. Chiral NaBH₄ was modified by four different ligands 3a–3d, chiral BH₃ and chiral AIP by four different ligands 4a–4d. Ligand 4c was synthesized for the first time in this work. Chiral NaBH₄ generated chiral alcohols of (R)-configuration and chiral BH₃ and chiral AIP of (S)-configuration with high enantiomeric excesses, were analysed by chiral HPLC. In order to determine the ee values by chiral HPLC, sixteen corresponding racemic alcohols, synthesized by reducing their corresponding ketones via NaBH₄, were used for chiral resolution on a Daicel OD HPLC column. The sixteen starting ketones were synthesized in this study by Friedel–Craft acylation. The new chiral alcohols were characterized by IR, NMR, (¹H and ¹³C), MS, elemental analyses and specific rotation. The reduction methods A, B and C were applied to these ketones for the first time in this study and were compared with each other. The relationship between the structure of the ketone and the yield and the enantiomeric excess was discussed.     

New pyrimidino-crown ether ligands

Eight new macrocyclic ligands containing the pyrimidine subcyclic unit ( 3-10 , Figure 1) have been prepared. Two of these new crown ethers are chiral. Pyrimidino-crowns 3-8 were prepared by treating the di-tosylate derivative of the appropriate oligoethylene glycol with 4-methoxy-5-raethyl-2,6-pyrimidinedimeth-anol in basic conditions. The yields were in the 30-50% range giving the crowns as viscous oils. Chiral dimethyl-substituted pyrimidino-crown 9 was prepared from 4-methoxy-5-methyl-2,6-pyrimidinedimethyl di-tosylate and chiral dimethyl-substituted tetraethylene glycol. Treatment of dimethyl 4-methoxy-5-methyl-2,6-pyrimidinedicarboxylate with the diamine derivative of chiral dibenzyl-substituted tetraethylene glycol gave the chiral dibenzyl-substituted pyrimidino-crown diamide 10. Starting 4-methoxy-5-methyl-2,6-pyrimidinedi-methanol was prepared by a six step process from acetamidine hydrochloride and diethyl oxalpropionate.     

丙烯／CO交替共聚物还原制备新型手性聚多元醇

手性Pd(Ⅱ)/P-PHOS(S)催化的丙烯/CO交替聚酮通过还原合成了一类新型手性聚多元醇.考察了4种还原剂LiAlH4,NaBH4,BH3·THF和Pd/C加氢对该聚酮的还原作用,其中LiAlH4和NaBH4可将聚酮分子链中羰基完全还原,生成手性交替聚多元醇,BH3·THF只能部分还原聚酮羰基,而Pd/C氢对聚酮没有还原作用.     

光学活性3-(1′-羟基乙基)-4-乙酰氧基-β-内酰胺的立体选择性合成

(1′R,3R,4R)-N-取代-3-(1′-羟基乙基)-4-乙酰氧基-β-内酰胺(3)是合成青霉烯和碳青霉烯类β-内酰胺抗生素的关键中间体.以廉价的L-抗坏血酸为原料,制得S-缩异丙氧叉甘油醛(5),与胺反应定量转变成相应的手性亚胺(6a～6d),6与双烯酮[2+2]环加成反应,高立体选择性地合成3(S)-乙酰基-β-内酰胺(Sa～8d),其非对映体过量由类似反应的80％提高到接近100％.8a经四步反应得到目标化合物3a.     

Convergent and Stereoselective Synthesis of Sarcophytol-Q Precursor: (11S)-3,7,11,15-Tetramethyl-11-hydroxy-14-oxo-3E,7E,12E-hexadecatrienal

A chiral precursor of sarcophytol-Q, (11S)-3,7,11,15-tetramethyl-11-hydroxy-14-oxo-3E,7E,12E-hexadecatrienal, was synthesized in a convergent and stereoselective manner starting from geraniol and 4-hydroxy-2-butanone in nine steps. The key steps were asymmetric Sharpless epoxidation, base-induced dehydrohalogenation rearrangement of chiral epoxy chloride 5 and the phase transfer catalytic coupling reaction of allylic phenyl sulfone 4 with chiral allylic chloride 3 .     

Synthesis and structural chemistry of alkali metal tris(HMDS) magnesiates containing chiral diamine donor ligands

Six alkali metal tris(HMDS) magnesiate complexes (HMDS, 1,1,1,3,3,3,-hexamethyldisilazide) containing chiral diamine ligands have been prepared and characterised in both the solid- and solution-state. Four of the complexes have a solvent-separated ion pair composition of the form [{M·(chiral diamine)(2)}(+){Mg(HMDS)(3)}(-)] [M = Li for 1 and 3, Na for 2 and 4; chiral diamine = (-)-sparteine for 1 and 2, (R,R)-TMCDA for 3 and 4, (where (R,R)-TMCDA is N,N,N',N'-(1R,2R)-tetramethylcyclohexane-1,2-diamine)] and two have a contacted ion pair composition of the form [{K·chiral diamine}(+){Mg(HMDS)(3)}(-)](n) [chiral diamine = (-)-sparteine for 5 and (R,R)-TMCDA for 6]. In the solid-state, complexes 1-4 are essentially isostructural, with the lithium or sodium cation sequestered by the respective chiral diamine and the previously reported anion consisting of three HMDS ligands coordinated to a magnesium centre. As such, complexes 1-4 are the first structurally characterised complexes in which the alkali metal is sequestered by two molecules of either of the chiral diamines (-)-sparteine (1 and 2) or (R,R)-TMCDA (3 and 4). In addition, complex 4 is a rare (R,R)-TMCDA adduct of sodium. In the solid state, complexes 5 and 6 exist as polymeric arrays of dimeric [{K·chiral diamine}(+){Mg(HMDS)(3)}(-)](2) subunits, with 5 adopting a two-dimensional net arrangement and 6 a linear arrangement. As such, complexes 5 and 6 appear to be the only structurally characterised complexes in which the chiral diamines (-)-sparteine (5) or (R,R)-TMCDA (6) have been incorporated within a polymeric framework. In addition, prior to this work, no (-)-sparteine or (R,R)-TMCDA adducts of potassium had been reported.     

Chirality induction of π-conjugated chains through chiral complexation

Chirality induction of π-conjugated polyanilines through chiral complexation with the chiral palladium(II) complexes was demonstrated to afford the chiral conjugated polymer complexes. Complexation of the emeraldine base of poly(o-toluidine) (POT) with the chiral palladium(II) complex bearing one labile coordination site led to the formation of the chiral conjugated polymer complex, which exhibited an induced circular dichroism (ICD) based on the chirality induction into a π-conjugated backbone. The mirror image of the CD signal was observed with the chiral conjugated polymer complex, which was obtained from the chiral palladium(II) complex possessing the opposite configuration. The chirality of the podand ligand moieties of the palladium complex is considered to induce a propeller twist of the π-conjugated molecular backbone. The crystal structure of the chiral conjugated complex of N-bis(4′-dimethylaminophenyl)-1,4-benzoquinonediimine (L³) as a model compound of the polyaniline revealed a chiral propeller twist conformation of the π-conjugated backbone. Furthermore, chiral complexation with the cationic palladium(II) complexes provided the ionic chiral conjugated complexes.