关键词： .enantioselective synthesis   shown in Fig  

摘要： Homochiral diene diols of type 1, derived biocatalytically by microbial dioxygenation of halogenated aromatic compounds, have served as precursors to a number of oxygenated natural products. Specifically, D-chiro-inositol (9), D-erythuronolactone (10), (+)-lycoricidine (14), (+)-kifunensine (19), and L-threosphingosine (25) have all been synthesized from 1.

关键词： .asymmetric synthesis   methyl ketone   Process Research   asymmetric amplification  

摘要： The asymmetric synthesis of L-699,392, a leukotriene antagonist, is reported. The main framework of the molecule is formed via a Heck reaction. The introduction of the asymmetric center was accomplished by the chiral reduction of prochiral ketone using B-chlorodiidopinocampheylborane. A very high asymmetric amplification was observed in which 95% ee product can be obtained from 70% optically pure alpha-pinene. A new reagent, which is prepared in situ from methylmagnesium chloride and lithium-hexamethyldisilazide, is used to convert the methyl ester to the methyl ketone in one step with essentially no impurities formed under the reaction conditions.

关键词： .achiral   enantiotopic   deprotonation   stereoselectionis   enantioselectivesynthesis  

摘要： The deprotonation of achiral alkyl carbamates with sec-butyllithium/(-)-sparteine proceeds with a high degree of chiral recognition to form substituted alcohols usually with greater-than-or-equal-to 95 % ee after reaction with electrophiles followed by deprotection. The stereoselection is kinetically controlled and a qualitative transition state model is proposed. Some studies, concerning the discrimination between both enantiomers of stereogenic alkyl carbamates and on its utilization for the kinetic resolution are reported. The competition between external and internal competition was investigated in few cases. - Finally, we disclose a short report on the enantioselective electrophilic substitution of 1-methylindene;here the origin of stereoselection is an thermodynamically driven epimerization of diastereomeric indenyl-lithium sparteine complexes.

关键词： 芳基甘氨酸   不对称合成   光学活性  

摘要： 介绍了利用手性唑啉衍生物的不对称诱导作用，合成具有光学活性的芳基甘氨酸的方法，芳基甘氨酸的总产率为１７％～２４％，光学产率为５．６％～１０．５％，共合成了５个具有光学活性的芳基甘氨酸。

关键词： Cram规则   不对称合成   有机化学   合成  

摘要： 本文对Ｃｒａｍ规则作了改进，把常用的Ｎｅｗｍａｎ投影式表达法改为Ｆｉｓｃｈｅｒ投＊式表达法，并将它应用于某些不对称合成，改进后的Ｃｒａｍ规则不仅能圆满地解释反应事实，且应用起来更为方便快捷。

关键词： 不对称合成   热力学   有机合成  

摘要： 本文首次建立了不对称合成反应中热力学函数之间的相互关系，阐明了不对称合成手性产率随构型熵和温度变化的规律，在不对称合成中具有重要的理论和实际意义．

关键词： 对映选择加成   苯甲醛   乙基锌   非线性效应  

摘要： 报道了以手性３－Ｎ，Ｎ，－二甲氨基－１，２－二苯基醇为配体，催化苯甲醛与乙基锌对映选择了加成反应中的非线性效应：１Ｒ，２Ｓ构型的配体使反应呈非线性效应；而１Ｓ，２Ｒ构型的配体使反应呈负非线性效应。