The Synthesis Of Chiral Thioureas And The Ionic Liquids Research Of Their Application In Asymmetric Synthesis

This dissertation includes two parts as follows.1. Synthesis of novel chiral thioureas and their application in catalytic asymmetric reactionsIn this part, three novel chiral thioureas10,16and19have been designed and synthesized from amine acid and D-Glucose. First, we used thiourea10as a catalyst for asymmetric Micheal reaction to obtain products with high yield (65-91%) and high diastereoselectivity (89:11->99:1) and high enantioselectivity(79-99%ee) Second, we explored the asymmetric F-C reaction with thioureas10,16and19as catalysts and found products could be obtained in satisfactorying yields (up to96%), but low enantioselectivities (up to40%ee).2. Synthesis of chiral ionic liquids and study of their application in asymmetric reactionsWe have designed and synthesized chiral ionic liquids28-30,37,44and46. We explored the asymmetric epoxidation of different aldehydes and benzyl bromide with28-30as catalysts and found that in the optimal condition the diaryl epoxides could be obtained in satisfactorying yields (41-67%) with excellent diastereoselectivities (91:9-100) and moderate enantioselectivities (42-72%ee). The ctalysts could be recycled and reused for at least six times without significant loss of activity. Moreover the organocatalyst37could conduct the Micheal products with good enantioselectivities and good yield, but for Aldol reaction the result is not satisfactory. We conducted the asymmetric D-A via chiral ionic liquids44and46, but both the yield and ee ratio are low.