Lewis base could catalyze the formation of a-trifluoromethyl alcohol from CF3SiMe3 and carbonyl-containing compounds. It was found that the α-trifluoromethyl alcohol could also be used to promote the synthesis in basic conditions.
A series of novel Meldrum＇s acid C60 derivatives were prepared in moderate yields from a convenient one-pot reaction of C60, the Meldrum＇s acid derivatives, 12 and 1,8-diazabicyclo-[5,4,0]-undec-7-ene （DBU） in toluene at room temperature under nitrogen atmosphere. All the new compounds were fully characterized by the spectral data and elemental analysis. A carbene intermediate mechanism was proposed for this reaction.
Pyrano[2,3-c]pyrazoles are a large class of heterocyclic compounds possessing many important biological activi...
Hongfei Zhang,Zhengqing Ye,Gang Zhao~* and Shizheng Zhu~* Key Laboratory of Synthetic Chemistry of Natural Substances and Key Laboratory of Organofluorine Chemistry,Shanghai Institute of Organic Chemistry,Chinese Academy of Science,345 Lingling Road,Shanghai 200032,China
Asymmetric reduction of diketones with borane reagents generated in situ using cheap and available NaBH4 and SnCl2 in the presence of （S）-（-）-α,a-diphenyl-2-pyrrolidinemethanol was successfully achieved to yield the corresponding chiral diols with excellent stereoselectivity and enantioselectivity. And the chiral diol was transformed into optically pure C2-symmetricl chiral amine or thioether.
The cycloaddition reactions of a-acetyoxyl propynes with difluorocarbene, generated from the decomposition of FSO2CF2CO2SiMe3 in DG in the presence of 10% of NaF at 120℃ gave readily a-acetyoxyl gem-difluorocyclopropenes. When these fluorinated compounds were hydrolyzed under alkaline condition at 0℃, α-hydroxyl cyclopropenones were produced predominantly whereas treated with catalytic amounts of BF3·Et2O in Et2O, α-acetyoxyl cyclopropenones were obtained.
Chiral cyclohexanones are common structural motifs occurring in a number of natural products with biological a...
Hongfei Zhang,Zhengqing Ye,Peng Li,Gang Zhao~* and Shizheng Zhu~* Key Laboratory of Synthetic Chemistry of Natural Substances and Key Laboratory of Organofluorine Chemistry,Shanghai Institute of Organic Chemistry,Chinese Academy of Science,345 Lingling Road,Shanghai 200032,China
Asymmetric epoxidation of α,β-unsaturated ketones has been extensively studied and several important procedures have been developed in the last decade. This review addresses the most significant advances in asymmetric epoxidation of α,β-unsaturated ketones using proline-derived α,α-diarylprolinols as catalysts. Special attention has been paid to the enantioselective epoxidation of chalcones, α,β-unsaturated trifluoromethyl, trichloromethyl ketones and β,γ-unsaturated α-keto esters based on the reseach of our group.
Enantioselective synthesis of functionalized fluorinated dihydropyrano[2,3-c]pyrazoles has been achieved via a diaminocyclohexane-thiourea catalyzed cascade Michael addition and Thorpe-Ziegler type cyclization in high yields （up to 98%） with moderate to good enantioselectivity （up to 90% ee）.
