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

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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