Study On The Catalytic Properties Of Chiral Tetraoxazoline Metal Complexes To 1,3-Dipolar Cycloaddition Reaction

So far, there were four chiral metal-catalysts for 1,3-DC: bisoxazolinyl-, TADDOL, shiffbases, binam-. Especially, chiral bisoxazolinyl-metal catalyst can improve the selectivity, catalyze achiral alkene and nitrone to chiral products. It is more avalable for synthesis of many natural chiral complexes. This paper attempts to control regio-, diastereo- and enantioselectivity between electron-deficient alkenes and nitrones catalyzed by Cu/Zn-tetra(oxazolinyl) phenyl complexes.In this paper, four chiral aminoalcohol, phenylglycinol, phenylalaninol, valinol, leucinol, were synthesized from a series of low-cost amino acid, catalyzed by NaBH4/I2, and the reaction conditions, reflux time, hydrolysis time, hydrolysis temperature were optimized. The optimal condition: reflux 20h, hydrolysis 50℃, 5h, and the yields of all products were over 90%.Four chiral tetra(oxazolinyl)phenyl were synthesized by one step of refluxing with water-separation. Discussed the influence of addition of DMF on the yield of tetra(oxazolinyl)phenyl. The results showed that: the rate of DMF/DMB was 10/60, all of the yields were above 95%, and products were characterized by IR, NMR, MS and so on.Two electron-deficient alkenes, 3-But-2-enoyl-oxazolidin-2-one and 3-Acryloyl-oxazolidin-2-one, were synthesized from crylic acid, butylene, urea and ethanolamine, characterized by IR and NMR.We study the 1,3-dipolar cycloaddition reaction of C,N-diphenylnitrone and two electron-deficient alkenes, 3-But-2-enoyl-oxazolidin-2-one and 3-Acryloyl-oxazolidin-2-one, catalyzed by Cu/Zn-tetra(oxazolinyl)phenyl as chiral metal catalysts. The results show that, enfluence on the reaction rate, reaction time of 3-Acryloyl-oxazolidin-2-one has reduced from 72h to 30h, reaction time of 3-But-2-enoyl-oxazolidin-2-one has reduced from 15 days to 7 days. The impact of regio-selectivity, regioselectivity of 3-Acryloyl-oxazolidin-2-one have been sign-ificantly improved by catalyzers, 3a/3b was from 50/50 of blank reaction to 100/0 of catalysis reaction. Reaction of 3-((E)-2-buteneacyl)-1,3-oxazolidine-2-one only have one regioproduct. The selectivity of endo/exo, a significant incre- ase in the reaction of 3-Acryloyl-oxazolidin-2-one and C,N-diphenylnitrone, endo/exo was improved from 20/80 to 99/1; furthermore, the reaction of 3-But-2-enoyl-oxazolidin-2-one and C,N-diphenylnitrone, endo/exo was increased from 32/68 to 99/1.