关键词： 固态超分子   不对称合成   柏木醇   4-对羟基苯基-3-丁烯-2-醇   主客体包结法   手性主体分子  

摘要： 利用羟醛缩合法和主客体包结法 (主体为柏木醇 )分别制备了一个客体 4-对羟基苯基 - 3 -丁烯 - 2 -酮和一个超分子化合物 .以四氢硼钠为还原剂 ,在固态超分子环境下将其中的客体还原为 4-对羟基苯基 - 3 -丁烯 - 2 -醇 ,硅胶薄板分离提纯得目的产物 ,通过对目的产物的检测 ,它具有光学活性 ,其比旋光度值为 +2 .44°.该结果表明 :在固态超分子中 ,具有单官能团的手性主体分子 (如柏木醇 )

关键词： ASYMMETRIC synthesis   ANILIDES   ENANTIOSELECTIVE catalysis  

摘要： Catalytic asymmetric N-allylation reaction of ortho-tert-butylanilide derivatives with diallyl carbonate proceeds in the presence of tol-BINAP-Pd catalyst to give chiral N-allyl ortho-tert-butylanilides of 32-44%ee in excellent chemical yields ( greater than or equal to 90%).

关键词： .asymmetric synthesis   enantiomeric excess   dithiane   thiolester   Acyl Anion Equivalent   Esquivel-Zamora   Synthesis of Salbutamol  

摘要： An enantioselective synthesis of (R)-salbutamol has been carried out using the chiral, C-2\ symmetric acyl anion equivalent, (1-R,3R)-1,3-dithiane 1,3-dioxide, which undergoes addition to an aromatic aldehyde with very high stereocontrol at 0 degreesC. Pummerer reaction and work-up with lithium ethanethiolate generated the alpha-hydroxy thiolester in high yield and further transformations led to the target compound with high enantiomeric excess.

关键词： ESTERS   ELECTROLYTIC reduction   ASYMMETRIC synthesis  

摘要： The electroreduction of Ar-substituted methyl cinnamates in acetonitrile gave all-trans cyclized hydrodimers stereoselectively (58similar to90% de). In all cases, small amounts (<10% yield) of meso hydrodimers were also formed. The electrolysis was performed conveniently using an undivided cell at a constant current. The transition states for the hydrocoupling were calculated with semiempirical methods. The all-trans cyclized hydrodimers were transformed to C-2-symmetric dl-3,4-diaryladipic acids and trans-3,4-diarylcyclopentanones. The chiral auxiliary [(1R)-exo]-3-exo-(diphenylmethyl)borneol, prepared from (1R)-(+)-camphor, was highly effective for the stereoselective hydrocoupling of its cinnamates by electroreduction. From the resulting hydrodimers, (3R,4R)-3,4-diaryladipic acid esters and (3R,4R)-3,4-diarylhexane-1,6-diols were synthesized in 87-95% ee.

关键词： Absolute configuration   Family Members   Natural products   Asymmetric synthesis   antipodes  

摘要： The relative and absolute configuration of the pneumocandin B-0 side chain has been established as (10R,12S)-dimethylmyristoyl by the stereocontrolled synthesis of both antipodes of the side chain acid and their comparison to a sample derived from the natural product.

关键词： AMINO acids   SULFUR compounds  

摘要： Addition of the Reformatsky reagent derived from ethyl bromodifluoroacetate to alkyl- and aryl-substituted N-tert-butylsulfinimines furnishes beta-tert-butylsulfinamyl-beta-substituted alpha,alpha-difluoroproponiates in diastereomeric ratios ranging from 80:20 to 95:5. The diastereomers are easily separated and the enantiomerically pure, protected beta-amino esters are readily transformed to the corresponding acid, amide, and amine derivatives as useful synthons for medicinal chemistry targets.

关键词： Redox reactions   Urea   Enantioselective synthesis   Complexation   Receptors  

摘要： [GRAPHICS] A new strategy for the asymmetric synthesis of chiral primary alpha-ferrocenylalkylamines has been utilized to generate homochiral redox-active receptors that bind chiral carboxylate anions with moderate enantioselectivity and undergo a redox response to complexation.

关键词： Hydrocarbons   Stereoselectivity   Enantioselective synthesis   Aromatic compounds   Solvents  

摘要： [GRAPHICS] highly diastereoselective addition of i-BuLi to a triethylmethylsulfinamide derived aldimine was used as the key step in the first asymmetric synthesis of (R)-didesmethylsibutramine, a metabolite of sibutramine for the potential treatment of CNS disorders.

关键词： β-氨基酸   不对称合成   研究进展   手性辅基   不对称催化   立体选择性  

摘要： β 氨基酸是一类在医药开发和生物化学研究中有重要用途的化合物 ,立体选择性地合成光学纯 β 氨基酸具有挑战性 .近 10多年来人们在该领域开展了许多工作 .

关键词： ASYMMETRIC synthesis   AMINO acids  

摘要： Polyhydroxylated sulfinimines derived from protected 1,2-O-isopropyliden-L-threoses undergo the sulfinimine-mediated Strecker syntheses to give alpha-amino nitriles in good yield and de. A double stereodifferentiation effect was not observed and the diastereoselectivity is controlled by the absolute configuration of the sulfinyl group. Hydrolysis of the amino nitriles afforded the lactone rather than polyoxamic acid.