Michael Type Addition Catalyzed by Sodium Azide

• Main Authors: Hsien-Chieh Chang, 張賢傑
• Other Authors: Chia-Hsi Yang
• Format: Others
• Language: zh-TW
• Published: 2010
• Online Access: http://ndltd.ncl.edu.tw/handle/06133495071638436066

碩士 === 中原大學 === 化學研究所 === 98 === In our speculation, in Michael type addition of alcohol to alkene, the catalyst is actually added to alkene in the first step. The intermediate then undergoes nucleophilic substition from alkoxide ion to form the product. Therefore, the catalyst should be a good Michael donor in the first step, and a good leaving group in the second step. We selected NaN3, NaNO2, Na2SO3 as the catalyst to catalyze for Michael type reaction of methanol and acrylonitrile, and found that they have similar catalytic properties. the catalytic effect of sodium azide is the best. It only takes 1.5 hours, the yield was 93%. Using NaN3 to catalyze the reaction of methanol and a series of electron-withdrawing group alkene, we find that the activity of alkene is: acrylonitrile> methyl vinyl ketone> methyl acrylate. When there is substition at β position, the reaction does not proceed. In the reaction of different alcohols with acrylonitrile : (1) both primary and secondary alcohols give good yields, but not tertiary alcohol. (2) even if the alcohol having alkenyl or alkynyl substituent, the reaction does proceed Based on the previous results, we also use N3- ion as a catalyst to Michael type addition of C-C formation. If the reactant has an acidic enough C-H (pKa≦25), it can be a Michael donor. In the case of penta-1,3-dione with methyl vinyl ketones other than the double Michael addition product (4c), a ring-closing product from 4c also was obtained as the minor product. By adding methyl vinyl ketone dropwise to penta-1,3-dione and the catalyst, the side product can be reduced to negligibly. This result also supports our mechanism. As a further test of our mechanism, CD3OD was used to replace CH3OH in the reaction of Michael addition of methanol to acrylonitrile, from 1H and 13C-NMR spectra of the product, we was obtained α-proton was replaced by deuterium. This result also supports our mechanism of the reaction.