关键词： 糖化学   不对称合成   溶液性质   缩水内醚糖   碳原子   脱保护   反应   卤代物   不饱和   自然界  

摘要： 本书共分七章，第一章是糖的基本概念、糖之间的关系、糖的形状及溶液性质；第二章主要涉及糖端基异头碳的性质及反应，详细地介绍了糖基酯、糖基卤代物、糖的氧苷（包括缩水内醚糖）、氮苷、硫苷、碳苷等；第三章主要介绍除端基异头碳外的其他碳原子的性质和反应，包括脱氧糖、不饱和糖、多羰基糖、支链糖等；第四章是讲述糖的羟基的性质及反应、保护和脱保护；第五章谈及寡糖合成的进展；第六章论述以糖为原料或辅剂的不对称合成第七章介绍自然界中存在的单糖、寡糖、多糖．

关键词： desymmetrization   cyclohexa-1,4-diene   intramolecular haloetherification   (+)-hydrobenzoin   ene acetal  

摘要： A novel asymmetric synthesis of the cyclohexane derivative functionalized by some substituents has been developed from the diene acetals (1), prepared from the corresponding diene aldehyde and (+)-hydrobenzoin. The treatment of 1 with NBS in the presence of MeOCH2CH2OH predominantly afforded 2 in a stereoselective manner. Subsequent alkylation of the methoxyethoxy group produced the optically active cyclohexene compounds (3) in good yields. The stereoselective chemical modification of the remaining olefin in 3 was made by OsO4-oxidation.

摘要： Research, inspired by nature, provides ample opportunity for discovery, ingenuity, and creative endeavor. For these reasons, the work and accomplishments presented herein focus on the total syntheses and related investigations of a variety of natural product derivatives, specifically (+)-nootkatone and jasmone. While the former consists of several independent projects: (a) an enantioselective synthetic route to (+)-nootkatone and derivatives, (b) examination of the valencane ring system, (c) determination of the absolute configuration of (+)-nootkatone, and (d) rearrangements of various sesquiterpenoid derivatives; the latter focuses on the construction of, -unsaturated carbonyl compounds, hetero Pauson-Khand substrates, via [3,3]-sigmatropic rearrangements.

关键词： METHYLENE-GAMMA-BUTYROLACTONES   ONE-POT SYNTHESIS   ALPHA-METHYLENE   SESQUITERPENE LACTONES   XANTHIUM-STRUMARIUM   ALLYLIC ALCOHOLS   TETRAHYDROFURAN DERIVATIVES   PALLADIUM(II) ACETATE   AROMATIC KETONES   VINYL ETHERS   Metathesis   allyl alcohol   vinyl ether   Asymmetric synthesis   4-Butyrolactone   alkenes   sesquiterpenoid lactones   one pot synthesis   Lactones  

摘要： The catalytic stereoselective Oshima-Utimoto reaction is useful for the construction of five-membered oxacycles from simple starting materials and was employed for the preparation of the lactone group in the asymmetric synthesis of (-)-11 alpha,13-dihydroxanthatin. Completion of the synthesis is facilitated by ring-closing enyne metathesis and alkene cross metathesis reactions.

关键词： Transfer reactions   Adsorption   Organic polymers   Stereoselectivity   Fungi  

摘要： Asymmetric reduction of beta-oxo ester to chiral beta-hydroxy ester by yeast cells is one of the most promising routes for synthesis of chiral pharmaceutical intermediates. But the stereoselectivity and initial substrate concentration of this asymmetric reduction reaction are usually unsatisfactory. When asymmetric reduction of ethyl 4-chloro-3-oxobutanoate to chiral ethyl 4-chloro-3-hydroxybutanoate by baker's yeast was chosen as the model reaction, it was investigated to improve the stereoselectivity and initial substrate concentration of this asymmetric reduction reaction by introducing resin to slowly release the substrate and in situ adsorb the product. The experiments indicated that the stereoselectivity could be promoted from about 78% to 95% with this technique, and the initial substrate concentration could be increased from 70 to 150 mmol/L, but the yield and stereoselectivity were still satisfactory with introducing resin.

关键词： PIPECOLIC ACID-DERIVATIVES   STEREOSELECTIVE-SYNTHESIS   ALKALOID SYNTHESIS   REVISED STRUCTURE   ENAMINONES   CHEMISTRY   ESTERS   KANOKO  

摘要： N-Sulfinyl delta-amino beta-ketoester enaminones, a new sulfinimine-derived chiral building block, undergoes, on hydrolysis in one pot, an intramolecular Michael addition followed by a retro-Michael-type elimination to give enantiopure 2,4,5-trisubstituted piperidines, a structural motif found in numerous biologically active alkaloids. This new chiral building block is readily prepared by treating N-sulfinyl delta-amino beta-ketoesters with dimethylformamide dimethyl acetal. This new protocol was illustrated with a concise formal asymmetric synthesis of marine alkaloid pseudodistomin B triacetate.

关键词： stereoselective synthesis   alkaloids   addition reactions   metathesis   dihydroxylations  

摘要： The first stereoselective synthesis of 1,4-dideoxy- 1,4-imino-D-Talitol has been achieved in 24% overall yield from conveniently protected (S)-glyceraldimine (1), which is easily prepared from inexpensive D-mannitol. The synthesis is based on the addition of vinylmagnesium bromide to this N-benzylimine followed by N-acylation, ring-closing metathesis and asymmetric dihydroxylation. In this synthesis as many as three stereogenic centres are constructed with total stereoselectivity.

关键词： Amides   Chemical synthesis   Enantioselective synthesis   Rearrangement   Molecular structure  

摘要： A new, efficient, and general asymmetric synthesis of enantiomerically pure trans-3,4-dialkyl-,gamma-lactones has been developed. The key steps are (1) copper-catalyzed three-component coupling of chiral amine, aldehyde, and alkyne, (2) acyl-Claisen rearrangement, and (3) iodolactonization. The products, chiral gamma-lactones, are versatile synthetic intermediates and structural units of natural products and modified nucleosides.

关键词： 不对称合成   中间体   不对称环氧化   受体阻滞剂   肾上腺素能   苯并吡喃   合成路线   反应产率   乙二醇   总收率   二氢   环化   烯化   药物  

摘要： (S，R，R，R）-奈必洛尔是一种新型、强效的β1-肾上腺素能受体阻滞剂降压药物．采用氧化／Wittig烯化一锅煮反应和Sharpless不对称环氧化／环化一锅煮反应，经八步反应，不对称合成出(S，R，R，R)-奈必洛尔的两个关键中间体1-6-氟-(2S)-3，4-二氢-2H-2-苯并吡喃]-(1R)-1，2-乙二醇和1-[6-氟-(2R)-3，4-二氢-2H-2-苯并吡哺]-(1S)-1，2-乙二醇．该合成路线工艺简单，单步反应产率高，八步反应总收率达19％．

关键词： pheromones   asymmetric synthesis   SAMP/RAMP-hydrazones   quaternary stereocenters   epoxide opening  

摘要： The asymmetric synthesis of (1S,3R,5R,7S)-(+)-sordidin and 7-epi-(1S,3R,5R,7R)-(-)-sordidin, both components of the natural male-produced aggregation pheromone of the banana weevil Cosmopolites sordidus (Germar), starting from 2,2-dimethyl-1,3-dioxan-5-one is described. Two of the stereogenic centers were generated by three alpha-alkylations of the corresponding RAMP-hydrazone. Diastereoselective epoxide opening as another key step of the synthesis employing the aza-enolate of 3-pentanone SAEP-hydrazone as nucleophile and subsequent acidic intramolecular acetalisation furnished the sordidin C-7 epimers in good overall yield (39%) as a 1.5:1 diastereomeric mixture. The epimers could be separated by preparative GC and thus, each of them could be obtained in high diastereomeric and enantiomeric purity (de >= 97 %, ee >= 98 %). ((c) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005).