Four chiral 1,1?bis(oxazolinyl)ferrocenes(1a-1d) have been prepared and used as ligands in the copper catalyzed asymmetric cyclopropanation of styrene with ethyl diazoacetate (EDA) and the magnesium catalyzed Diels-Al...Four chiral 1,1?bis(oxazolinyl)ferrocenes(1a-1d) have been prepared and used as ligands in the copper catalyzed asymmetric cyclopropanation of styrene with ethyl diazoacetate (EDA) and the magnesium catalyzed Diels-Alder reaction between 3-acryloyl-2-oxazolidinone and cyclopentadiene. Enantioselectivities up to 24% and 41%, respectively, for cyclopropanation and Diels-Alder reaction were observed.展开更多
In order to have efficient and highly stereoselective cyclopropanating reagents, the cyclopropabation reaction of ethylene promoted with Samarium（Ⅱ） carbenoid [Simmons-Smith（SS）reagent] were studied by means of B...In order to have efficient and highly stereoselective cyclopropanating reagents, the cyclopropabation reaction of ethylene promoted with Samarium（Ⅱ） carbenoid [Simmons-Smith（SS）reagent] were studied by means of B3LYP hybrid density functional method. The geometries for reactants, transition states and products are completely optimized. All transition states were verified by the vibrational analysis and the intrinsic reaction coordinate （IRC） calculations. The results showed that, identical with the lithium carbenoid, CH3SmCH2X（X=Cl, Br and Ⅰ） can fairly react with ethylene via both methylene transfer pathway （pathway A） and carbometalation pathway （pathway B）. And the cyclopropanation reaction via methylene transfer pathway proceeds with a lower barrier and at lower temperatures.展开更多
The packed density, detonation velocities, and detonation pressures of a series of cyclopropane derivatives were investigated to look for high energy density compounds. For exploring the possibility of synthesis, the ...The packed density, detonation velocities, and detonation pressures of a series of cyclopropane derivatives were investigated to look for high energy density compounds. For exploring the possibility of synthesis, the bond order, heats of formation(HOF), bond dissociation energy(BDE), and characteristic height were calculated. Based on our results, A3 has the best detonation characters. Both A1 and A2 showed comparative detonation parameters and compact sensitivity with RDX, and could be regarded as the candidates of high energy density molecules.Both the heats of formation and explosive heats rose with the increase of nitrimino groups and the strain energy of three-membered ring. For A1 compound, pyrolysis mechanism might be a mix one(breakages of C–C and N–NO2 bonds). However, for A2 and A3 compounds, the N–NO2 is the trigger bond in explosive reactions. Our results may provide the basic information for further study of this kind of compounds.展开更多
文摘Four chiral 1,1?bis(oxazolinyl)ferrocenes(1a-1d) have been prepared and used as ligands in the copper catalyzed asymmetric cyclopropanation of styrene with ethyl diazoacetate (EDA) and the magnesium catalyzed Diels-Alder reaction between 3-acryloyl-2-oxazolidinone and cyclopentadiene. Enantioselectivities up to 24% and 41%, respectively, for cyclopropanation and Diels-Alder reaction were observed.
基金This work was supported by the Northwest Normal University Science Foundation of Gansu Province （No. NWNU-QN-2001-08）.
文摘In order to have efficient and highly stereoselective cyclopropanating reagents, the cyclopropabation reaction of ethylene promoted with Samarium（Ⅱ） carbenoid [Simmons-Smith（SS）reagent] were studied by means of B3LYP hybrid density functional method. The geometries for reactants, transition states and products are completely optimized. All transition states were verified by the vibrational analysis and the intrinsic reaction coordinate （IRC） calculations. The results showed that, identical with the lithium carbenoid, CH3SmCH2X（X=Cl, Br and Ⅰ） can fairly react with ethylene via both methylene transfer pathway （pathway A） and carbometalation pathway （pathway B）. And the cyclopropanation reaction via methylene transfer pathway proceeds with a lower barrier and at lower temperatures.
基金supported by the National Natural Science Foundation of China(51374121)
文摘The packed density, detonation velocities, and detonation pressures of a series of cyclopropane derivatives were investigated to look for high energy density compounds. For exploring the possibility of synthesis, the bond order, heats of formation(HOF), bond dissociation energy(BDE), and characteristic height were calculated. Based on our results, A3 has the best detonation characters. Both A1 and A2 showed comparative detonation parameters and compact sensitivity with RDX, and could be regarded as the candidates of high energy density molecules.Both the heats of formation and explosive heats rose with the increase of nitrimino groups and the strain energy of three-membered ring. For A1 compound, pyrolysis mechanism might be a mix one(breakages of C–C and N–NO2 bonds). However, for A2 and A3 compounds, the N–NO2 is the trigger bond in explosive reactions. Our results may provide the basic information for further study of this kind of compounds.
