| Budget Amount *help |
¥3,700,000 (Direct Cost: ¥3,700,000)
Fiscal Year 2006: ¥1,300,000 (Direct Cost: ¥1,300,000)
Fiscal Year 2005: ¥2,400,000 (Direct Cost: ¥2,400,000)
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| Research Abstract |
Recently, proline or its derivatives-catalyzed asymmetric carbon-carbon bond-forming reactions such as aldol reaction, the Michael addition, and Mannich-type reaction were studied intensively by many organic chemists. Excellent enantioselectivity was attained in various types of organocatalytic asymmetric reactions, but the Michael addition has some serious limitations. For example, there are scattered examples over 90% ee, and substrate generality is not so high. On the other hand, we have developed a novel asymmetric Michael addition reaction of ketone to b-nitrostyrene and its derivatives using (5)-homoproline as a chiral organocatalyst. The reaction was performed in a highly diastereoselective and enantioselective manner over 90% ee. Furthermore, we have developed solvent-free organocatalytic asymmetric conjugate addition of thiols to a, b-unsaturated aldehydes. In the presence of well-designed organocatalyst, the reaction proceeds without any organic solvents, giving the corresponding chiral sulfides in almost enantiomerically pure form (up to 99% ee). Moreover, b, b-disubstituted a, b-unsaturated aldehydes also reacted with phenylmethanethiol. This method is environment-friendly, economical, and convenient.
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