The Application Of Novel Chiral First Amine Catalysts In Aldol Reaction

Asymmetric organic synthesis is one of the most attractive research areas in organic synthesis. As a new method for asymmetric synthesis, enantioselective organocataiysis is more and more popular, so it has become a chemical challenges to explore many new and effective small molecular catalysts. The asymmetric aldol reaction is considered to be one of the important reaction of the carbon-carbon bond forming. It provides an atom-economic approach toβ-hydroxy-carbonyls which make up a large family of chiral intermediates for synthesis of many drugs. In previous research, most of the small molecular catalysts are proline or their derivatives, proline is second amine but few first amine catalysts were reported.In this thesis, a series of new primary amine catalysts were synthesized from readily available amino acid. Moreover, extension of acetone and 3-pentylone to aryl aldehydes are observed by addition of optimal additives.1. A series of catalysts Va-Vg were synthesized and the effects on the catalytic activity and enantioselectivity were studied.2. The catalytic activity and enantioselectivety of the suitable catalyst V f have been studied in organic phase in the influence of the type and amount of the additives, different solvents, temperature and the amount of catalyst etc.3. The results indicated that different additives have great effects on the enantioselectivity . 2, 4-dinitrophenol is the optimal additive among them which can raise the ee from 56% to 93%. The amount of additive and catalyst make little effect on the results. Low temperature can increase enantioselectivity. The most important is that we expand the scope of the substrate , the aldol reaction of 3-pentylone and aryl aldehydes leads to the formation of syn product with high yield, excellent diastereoselectivity and enantioselectivity in neat 3-pentylone.