Preparation of a chiral organocatalyst and their application for asymmetric carbon-carbon bond construction

我们已经开发了一种实用的合成手性内酰胺作为一种新的手性积木的许多不对称诱导。手性内酰胺的动力学拆分及消旋化反应收率> 99%ee，手性内酰胺的化学转化经10步反应得到手性（-）-epi-lentiginosin，收率20%，对映体过量没有损失，同时也实现了Pulchellalactam及其相关化合物的简便合成。以市售廉价的柠康酸酐为原料，经5步反应，总收率为55%，经8步反应，总收率为43%。在无有机溶剂的水相中，研究了甘氨酸叔丁酯-二苯甲酮Schiff碱的手性相转移催化不对称烷基化反应。在水介质中反应顺利进行，得到的目标产物产率高于标准的液-液两相条件。 ...更多信息 一个。在水介质中，Schiff碱原位水解生成二苯甲酮的反应受到抑制。我们发展了直接不对称交叉羟醛缩合反应，该反应可在水中进行，无需添加有机溶剂。具有长疏水烷基链的双功能催化剂有效地催化反应，并以优异的产率提供所需的羟醛产物，具有高对映体过量，即使当仅使用等摩尔比的供体和受体时。这些结果揭示了一个有效的设计策略，为发展水性有机催化systems.We开发了一个直接的，不对称迈克尔反应，可以在盐水或海水中进行，而无需添加有机溶剂。具有长疏水烷基链的双功能催化剂有效地催化Michael反应，并以优异的产率和高对映体过量提供所需的产物，即使当仅使用等摩尔比的供体与受体时。少

We have developed a practical synthesis of the chiral lactam as a new chiral building block for a multitude of asymmetric induction. Excellent kinetic resolution of the lactam, followed by racemization of the resolved product provided the chiral lactam in good yield with >99% ee. Chemical transformation of the lactam furnished chiral (-)-epi-lentiginosin in 20% yield in 10 steps with no loss of enantiomeric excess.Convenient synthesis of Pulchellalactam and its related compounds was also accomplished. Total yields of (Z)-Pulchellalactam and (E)-Pulchellalactam were 55% for 5 steps and 43% for 8 steps from commercially available and inexpensive citraconic anhydride, respectivelyChiral phase-transfer catalyzed enantioselective alkylations of tert-butyl glycinate-benzophenone Schiff base were investigated in aqueous media without any organic solvent. Reactions in aqueous media smoothly proceeded to give the desired product in higher yield than under standard liquid-liquid biphasic conditi … More ons. In aqueous media the formation of benzophenone, which was caused by in-situ hydrolysis of Schiff base, was depressed.We have developed direct asymmetric cross-aldol reactions that can be performed in water without addition of organic solvents. A bifunctional catalyst with a long hydrophobic alkyl chain efficiently catalyzed the reactions and afforded the desired aldol products in excellent yield with high enantiomeric excess, even when only an equal molar ratio of the donor and acceptor was used. These results reveal an effective design strategy for the development of aqueous organocatalytic systems.We have developed a direct, asymmetric Michael reaction that can be performed in brine or seawater without addition of organic solvents. A bifunctional catalyst with long hydrophobic alkyl chains efficiently catalyzed Michael reactions and afforded the desired products in excellent yield with high enantiomeric excess, even when only an equal molar ratio of the donor to acceptor was used. Less