一个简捷、高效合成松叶蜂性信息素的方法

以从甾体皂甙元降解的废弃物获取的(4R)-甲基-5-溴戊酸甲酯(4)为起始原料, 通过4与正庚基溴化镁选择性的偶联反应, 经关键合成中间体(4S)-甲基溴代十二烷(7)分别以52%和49%的总收率合成了松叶蜂性信息素(2S,3S,7S)-3,7-二甲基十五-2-醇乙酸酯(2)和丙酸酯(3).     

Stereoisomeric Separation of Derivatized 2-alkanols Using Gas Chromatography-Mass Spectrometry: Sex Pheromone Precursors Found in Pine Sawfly Species

Stereoisomers of long-chain secondary alcohols are used as sex pheromone precursors among pine sawflies and some species can be severe pine forest pests. To use their pheromone in environmentally friendly pest management, methods are needed that can determine the stereochemistry of the precursor alcohols. Combinations of 11 acid chloride derivatives and 10 GC columns were evaluated for separation of stereoisomers of 3,7-dimethylundecan-2-ol, 3,7-dimethyldodecan-2-ol, 3,7-dimethyltridecan-2-ol, 3,7-dimethyltetradecan-2-ol, and 3,7-dimethylpentadecan-2-ol. Derivatization with (S)-2-acetoxypropionyl chloride in combination with a Chiraldex B-PA column separated all eight stereoisomers of 3,7-dimethylundecan-2-ol, 3,7-dimethyldodecan-2-ol, and 3,7-dimethyltridecan-2-ol. A combination of two different derivatization methods was needed to separate all stereoisomers of the longer chained alcohols 3,7-dimethyltetradecan-2-ol and 3,7-dimethylpentadecan-2-ol. A female extract of the pine sawfly Neodiprion lecontei was also analyzed and the stereochemistry of the sex pheromone alcohol precursor was determined to be (2S,3S,7S)-3,7-dimethylpentadecan-2-ol at an amount of about 7 ng/female. This paper presents the first GC-MS separation of all eight stereoisomers of 3,7-dimethylundecan-2-ol, 3,7-dimethyldodecan-2-ol, and 3,7-dimethyltridecan-2-ol in a single analytical run and also the first GC-MS determination of the stereochemistry of the sex pheromone precursor found in females of N. lecontei.     

茚及其衍生物的催化不对称合成

茚及其衍生物广泛存在于自然界中,其中多官能团化的茚类化合物大多具有重要的生物活性,因而非常具有成为药物的先导化合物的潜力。特别是茚类化合物的不对称合成吸引了有机化学家们的广泛关注,最近有许多相应的合成方法研究被报道,包括外消旋体拆分、手性辅基及底物诱导的合成和手性催化合成等。本文总结了茚及其衍生物的催化不对称合成研究进展,重点介绍过渡金属及有机小分子不对称催化反应,并对该领域的研究前景进行了展望。     

Synthesis of the Stereoisomers of the Sex Pheromones of the Southern Corn Rootworm

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利用甾体皂甙元氧化降解废弃物(R)-4-甲基-δ-戊内酯合成松叶蜂主要性信息素(2S,3S,7S)-3,7-二甲基-2-十五醇乙酸酯和丙酸酯

首次利用甾体皂甙元氧化降解废弃物(R)-4-甲基-δ-戊内酯合成了松叶蜂性信息素(2S,3S,7S)-3,7-二甲基-2-十五醇乙酸酯(2)和丙酸酯(3). 甾体皂甙元氧化降解废弃物(R)-4-甲基-δ-戊内酯首先被转化成为性质稳定易保存的(R)-5-溴-4-甲基戊酸甲酯(5), 化合物5经过偶联、还原、溴代、环氧加成开环和酰化反应给出目标分子. 本研究结果不仅为松叶蜂性信息素化合物2和3提供了一个简洁有效的合成方法, 同时也丰富了资源化学(即基于资源性化合物合理利用的有机合成化学)的内涵.     

Facile Asymmetric Synthesis of α-Amino Acids Employing Chiral Ligand-Mediated Asymmetric Addition Reactions of Phenyllithium with Imines

A three-step methodology involving an external chiral ligand-mediated asymmetric addition of phenyllithium to an anisidine imine, oxidative removal of N-PMP group, and finally oxidative conversion of the phenyl group to a carboxyl group provides a facile synthesis of optically pure α-amino acid derivatives bearing a bulky α-substituent.     

Gas chromatographic enantiomer separation of chiral ketones — Order of elution and configurational stability of oxime derivatives

Summary Oximes of chiral ketones can be separated into enantiomers by capillary gas chromatography on the chiral polysiloxanes XE-60-L-valine-(S)- or (R)--phenylethylamide. Usually predominantly E-isomers are formed and are better separated than Z-isomers. From time-dependent gas chromatographic measurements it can be concluded that the oximes are configurationally stable and that racemization during oxime formation is negligible. The order of elution of enantiomers depends on the structure of the ketone and is different for aliphatic and alicyclic compounds.     

Asymmetric total synthesis of the indole alkaloid cyclopiazonic acid and first structure-activity data

The indole alkaloid α-cyclopiazonic acid (CPA) is one of the few known inhibitors of sarco(endo)plasmic reticulum Ca²⁺-ATPase (SERCA) besides the terpenoids thapsigargin and artemisinin. We report here the first asymmetric total synthesis of cyclopiazonic acid by a modification of the Knight synthesis, currently the most efficient route to CPA. First structure-activity data of CPA derivatives and stereoisomers are presented and will be discussed in connection with the published crystal structures of CPA-SERCA complexes.     

Syntheses of homochiral 1,2-ferrocene-functionalized Lewis acids and acid/base pairs

We report a facile approach for the synthesis of homochiral 1,2-disubstituted ferrocene-functionalized Lewis acids and acid/base pairs. The synthesis is based on chiral induction facilitated by the ortho sulfinyl subsitutent in S-Fc{S(O)p-tol}, S-1, to obtain the key intermediate S,S_p-1,2-fc{S(O)p-tol}(BMes₂), S,S_p-2a (p-tol = C₆H₄Me-4, Mes = C₆H₂Me₃-2,4,6). Subsequent substitution of the -S(O)p-tol substituent in S,S_p-2a gives access to a range of enantiomerically pure S_p-1,2-ferrocene-functionalized Lewis acids and acid/base pairs including the first homochiral 1-phosphino-2-borylferrocene. Enantiomeric excesses (e.e.s) of >95% have typically been achieved using this methodology.     

Stereoselective synthesis of (2S,3S,7S)-3,7-dimethylpentadec-2-yl acetate and propionate, the sex pheromones of pine sawflies

The stereoselective synthesis of (2S,3S,7S)-3,7-dimethylpentadec-2-yl acetate (2) and propionate (3) was accomplished by utilizing the cheap and easily available chiron (R)-4-methyl-δ-valerolactone (4). The key steps were chelation-controlled addition of Gilmann reagent to chiral β-alkoxy aldehyde 12 and the Cu(I)-catalyzed coupling of Grignard reagent with bromoester 5 in the presence of NMP.     

Practical Syntheses of Some Insect Sex Pheromones, 10- and 12-Alken-1-ol Acetates

Some insect sex pheromones 10-dodecen-1-ol acetates 5a(Z/E) and 12-tetradecen-1-ol acetates 5b(Z/E) have been synthesized from cis-13-docosenoic acid la and cis-15-tetracosenoic acid Ib via the isomerization of key intermediates 11-dodecen-1-ol acetate 4a and 13-tetradodecen-1-ol acetate 4b.     

Insect Pheromones and Their Analogs. LXI. Synthesis of 4E,10Z-Tetradecadien-1-ylacetate, a Component of the Lithocolettis ringoniella Sex Pheromone

A new scheme for synthesizing 4E,10Z-tetradecadien-1-ylacetate, the principal component of the apple leaf miner(Lithocolettis ringoniella)sex pheromone, is developed using a highly stereoselective Claisen rearrangement     

Stereoselective and Enantioselective Syntheses of the Four Stereoisomers of Muscol from (3RS)‐Muscone

Two trans stereoisomers of 3‐methylcyclopentadecanol (=muscol), (1R,3R)‐ 2 and (1S,3S)‐ 2 , were efficiently synthesized from (3RS)‐3‐methylcyclopentadecanone (=muscone; (3RS)‐ 1 ) by a highly stereoselective reduction (Scheme). L‐Selectride^® (=lithium tri(sec‐butyl)borohydride) was used, followed by the enantiomer resolution by lipase QLG (Alcaligenes sp.). The cis stereoisomers of muscol, (1S,3R)‐ 2 and (1R,3S)‐ 2 , were obtained by the Mitsunobu inversion of (1R,3R)‐ 2 and (1S,3S)‐ 2 , respectively (Scheme). The absolute configuration of (1R,3R)‐ 2 was determined by X‐ray crystal‐structure analysis of its 3‐nitrophthalic acid monoester, 2‐[(1R,3R)‐3‐methylcyclopentadecyl hydrogen benzene‐1,2‐dicarboxylate ((1R,3R)‐ 3b ), and by oxidation of (1R,3R)‐ 2 to (3R)‐muscone.     

不对称冠醚碲碳菁染料的合成

合成了５种不对称冠醚碲碳菁染料．对合成关键中间体冠醚苯并碲唑所用的４－硝基苯并１５－冠－５的还原酰化方法进行了改进，比较和研究了杂原子在同一主族的４个菁染料的可见吸收光谱，计算了它们的“Ｂｒｏｏｋｅｒ偏差”     

1,2,4-三苯基环戊二烯的合成及其烷基化反应

测定了颇哪醇在酸性条件下所得的脱水产物的分子结构.结果表明,在酸性条件下颇哪醇的脱水反应优于重排反应,由此合成了1,2,4-三苯基环戊二烯.该环戊二烯衍生物的烷基化反应,在通常条件下优先发生在碳环的第5位碳原子上,但在苛刻的剧烈反应条件下,进而发生在碳环的第3位碳原子上.讨论了脱水反应和烷基化反应的机理.     

Synthetic Applications of the Baylis–Hillman Reaction: Simple and Convenient Synthesis of Five Important Insect Pheromones

A simple and convenient synthesis of five important insect pheromones by means of Baylis–Hillman adducts is described, i.e., of (2E,4S)‐2,4‐dimethylhex‐2‐enoic acid ( 1 ), a mandibular‐gland secretion of the male carpenter ant in the genus Camponotus, of (+)‐(S)‐manicone ( 2 ) and (+)‐(S)‐normanicone ( 3 ), two mandibular‐gland constituents of Manica ants, and of (+)‐dominicalure‐I ( 6 ) and (+)‐dominicalure‐II ( 7 ), two aggregation pheromones of the lesser grain borer Rhyzopertha dominica (F). For the first time, the potential of the Baylis–Hillman chemistry for the stereoselective synthesis of trisubstituted olefins was successfully applied to the synthesis of these pheromone compounds.     

Asymmetric Synthesis of a Quaternary Carbon Stereogenic Center by Organocatalysis Using a Primary Amino Acid and Its Salt

In this personal account, our recent developments on the asymmetric synthesis of a quaternary carbon stereogenic center by organocatalysis using a primary amino acid and its salt as a catalyst are described in three chapters: (1) conjugate addition to nitroalkenes and vinyl ketones, (2) nucleophilic addition to π-allyl palladium complexes, and (3) nucleophilic substitution reactions with allyl and propargyl halides. By these methods, asymmetric α-allylation of α-branched aldehydes and ketones smoothly proceeded to give γ-nitroaldehydes, ketoaldehydes, α-allylated aldehydes, and α-allylated β-ketoesters possessing a quaternary carbon stereogenic center in good yields with high enantioselectivities.     

手性膦氮配体的合成及其钯配合物催化的不对称烯丙基烷基化反应

以价廉的天然产物辛可宁和奎宁为原料,在温和的条件下方便地合成了两个手性膦氮配体.考察了它们与过渡金属钯配合物在不对称烯丙基烷基化反应中的催化活性和不对称诱导作用.在1,3-二苯基-2-烯丙基-1-醇的乙酸酯与丙二酸二甲酯的反应中,两个配体均表现出中等的手性诱导活性(最高为73.5%e.e.).     

芳基取代四甲基环戊二烯基铼羰基化合物的合成、晶体结构及催化性能

芳基取代的四甲基环戊二烯 C₅HMe₄Ar（Ar=Ph,4-CH₃Ph,4-OCH₃Ph,4-ClPh,4-BrPh） 分别与Re₂（CO）₁₀在二甲苯中加热回流,得到了5个单核配合物[（η⁵-C₅Me₄Ar）Re（CO）₃]（Ar=Ph （1）,4-CH₃Ph （2）,4-OCH₃Ph （3）,4-ClPh （4）,4-BrPh （5））。通过元素分析、红外光谱、核磁共振氢谱对配合物1~5的结构进行了表征,用X射线单晶衍射法测定了配合物的结构。同时,研究了这五种配合物在芳香族化合物Friedel-Crafts烷基化反应中的催化活性。