| Budget Amount *help |
¥2,100,000 (Direct Cost: ¥2,100,000)
Fiscal Year 1996: ¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 1995: ¥1,400,000 (Direct Cost: ¥1,400,000)
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| Research Abstract |
Cyanuric fluoride was found to be effective for the activation of alkenylboronic acids and the activated alkenylboronic acids reacted with alpha, beta-unsaturated ketones through a 1,4-addition manner to provide gamma, delta-unsaturated ketones selectively. As a variety of functional groups both in alkenyl boronic acids and alpha, beta-unsaturated ketones can tolerate under the reaction conditions, polyfuncionlized gamma, delta-unsaturated ketones can be prepared directly by the 1,4-addition reaction of the functionalized alkenylboronic acids to the functionalized alpha, beta-unsaturated ketones using cyanuric fluoride as activating reagent.
It was also found that the 1,4-addition reaction rate of alkenylboronic acids to alpha, beta-unsaturated ketones was influenced by the substituents on ketones. The balky substituents such as t-butyl group on beta-position of carbonyl group disturb the 1,4-addition reaction drastically. On the other hand, any alkyl substituents at alpha-position have large effect to reduce the reaction rate. The alkenylboronic acids activated by cyanuric fluoride can discriminate the two alpha, beta-unsaturated ketone functions of unsymmetrical alpha, beta, alpha', beta'-unsaturated dienones when the rate reducing substituents were introduced into only one of their double bonds. The alkenylboronic acids reacted from the more reactive site of dienones selectively to give alpha, beta, gamma', delta'-unsaturated dienones. The introduction of other nucleophiles into the less reactive alpha, beta-unsaturated ketone part of the resulting dienones is possible using more reactive organometallic species.
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