关键词： Alcohols   Ketones   Stereoselectivity   Enones   Post-translational modification  

摘要： The enantioselective syntheses of daumone and two analogues have been achieved in seven to eight steps. This route relies upon a diasteroselective palladium-catalyzed glycosylation reaction for the formation of the anomeric bond. The asymmetry of the sugar and aglycone portion of daumone were introduced by Noyori reduction of an acylfuran and a propargyl ketone. A highly diastereoselective epoxidation and reductive ring opening established the desired C-2 and C-4 stereochemistry of daumone.

关键词： AROMATIC compounds   RING formation (Chemistry)   CHEMICAL reactions   GRIGNARD reagents   ORGANIC compounds   ORGANIC chemistry  

摘要： [GRAPHICS] The enantio-controlled synthesis of trans-4,5-benzhydrindan-1-ones was achieved by means of a stereoselective [4+2] cycloaddition of o-quinodimethanes generated by a thermal cleavage of benzocyclobutene derivatives as a key step. The chiral substrates of the thermal reaction were synthesized by a diastereoselective Grignard addition to the chiral O-isopropylideneglyceroketones connected to a benzocyclobutene ring, which were simply prepared from D-mannitol as a chiral source. This approach can provide a new efficient access to A-nor B-aromatic steroidal compounds.

关键词： Ligands   Stereoselectivity   Addition reactions   Organic compounds   Conjugate acid-base pairs  

摘要： A general route to enantioenriched tert-butyl 3,3-diarylpropanoates is presented. These useful building blocks are prepared via an asymmetric rhodium-catalyzed conjugate addition of arylboronic acids to unsaturated tert-butyl esters in the presence of chiral dienes as ligands. The addition of both electron-poor and electron-rich boronic acids proceeds smoothly with various enoates in 63-90% yield with high enantioselectivites (89-94% ee).

关键词： Reagents   Alcohols   Enantioselective synthesis   Ethers   Pharmaceuticals  

摘要： An efficient and stereocontrolled total synthesis of (+)-SCH 351448, a novel activator of low-density lipoprotein receptor promoter, has been achieved with a longest linear sequence of 21 steps. Key steps include applications of the recently developed asymmetric allyl- and crotylsilane reagents and a new protodesilylative version of the tandem silylformylation/allyisilylation reaction, which provides an efficient synthesis of 1,5-syn-diols.

关键词： CARBYNES   COMPLEX compounds   DRUGS   SERTRALINE   AROMATIC compounds   ALDEHYDES  

摘要： Compounds incorporating diarylmethine stereogenic centers are found innatural products and a number of notable Pharmaceuticals,such as tolterodine ***,the stereoselective preparation of building blocks leading to these ischallenging,particularly when little differentiates the two arenes electronically or *** especially problematic in cases where the only differentiation occurs at the para position ofthe aromatic *** current state of the art for the preparation of nonracemic3,3-diarylpropanals is the amine-catalyzed addition of aromatic nu-cleophiles to 3-substitutedacrolein derivatives(74-92% ee).

关键词： 手性化合物   不对称合成   固体催化剂   手性药物   生命过程   手性分子   生命体系   相互作用   生物活性  

关键词： 手性辅基法   不对称合成   α-氨基酸   甘氨酸等当体  

摘要： 特殊结构的α-氨基酸对于生命过程研究和生物医药开发有重要意义.不对称合成α-氨基酸的方法学中,手性辅基方法是较多研究和应用的领域.介绍了该方法近二十年来的发展,对近十年的甘氨酸等当体合成策略做了详尽述评.

关键词： L-脯氨酸   D-脯氨酸   D-脯氨酰胺   不对称合成   消旋  

摘要： 以L脯氨酸为起始原料,运用不对称转换的方法,以S酒石酸为拆分剂,合成D脯氨酸。然后进一步以手性源技术通过上保护基、酯化、氨化和脱保护基等步骤,不对称合成D脯氨酰胺。选择苄氧羰基氯为保护基,研究酰胺化的最佳实验条件是:氯甲酸乙酯与N苄氧羰基D脯氨酸的物质的量此为1.1。温度-5℃,通氨1h(300mL/min)后,静置36h,用Pd/C催化剂通氢气脱保护基。D脯氨酰胺的收率达到78.7%,比原不上保护基的路线收率提高1倍以上,光学纯度为99.3%,不易发生消旋等副反应。同时研究了pH值、温度及消旋时间对D脯氨酰胺消旋的影响。

关键词： (-)-Epibatidine   生物碱   不对称合成  

摘要： 小分子生物碱Ep ibatid ine的合成已经引起了各国化学家的极大关注,但大部分的合成路线得到的是Ep ibatid ine的一对外消旋体,本文综述了天然(-)-Ep ibatid ine的合成研究.

关键词： 1,3-偶极环加反应   不对称合成   立体选择性   手性配体   络合物  

摘要： 综述了手性配体金属络合物催化剂催化1,3-偶极环加成反应的研究进展。主要介绍了唑硼烷催化剂以及α,α,α’,α’-四芳基-1,3-二氧戊环-4,5-二甲醇、双唑啉、联萘二酚等手性配体的金属络合物在不同反应中的立体选择性。