Several borohydride reagents: sodium borohydride, sodium cyanoborohydride, soudium acetoxyborohydride and soudium triacetoxyborohydride were screened, respectively, for the reduction of 7-demethylsinomenine, which was an α,β-dicarbonyl compound derived from sinomenine. Highly regio-and stereo-selectivity was acquired when sodium cyanoborohydride or NaBH(OAc)3 was used. The product was structurally confirmed as 7R configuration by NMR, X-ray crystal diffraction analysis. Some preliminary discussion was also made on the mechanism of the selective reduction.
LI Yu-fengBU Qing-minQIAN YiPAN YiLI Jian-xinHUANG Le-qunZHU Hong-jun
The combination of benzamide and NCS was found to be an efficient nitrogen/halogen source for aminohalogenation of β-nitrostyrenes.The reaction was convenient to carry out by using 4-dimethylaminopyridine as the catalyst,resulting in vicinal dichlorinated haloamino nitroalkanes with opposite regiochemistry to that generated from other electron-deficient olefins observed previously.The reaction proceeded smoothly at room temperature with good yields and excellent regioselectivities.A mechanism involving a chloronium intermediate was proposed to explain the resulting regiochemistry.The current system explored a new type of nitrogen sources for aminohalogenation of functionalized olefins.
ZHI SanJun1,2,MEI HaiBo1,ZHANG GuangQian1,SUN Hao1,HAN JianLin1,LI GuiGen4 & PAN Yi1,3 1 School of Chemistry and Chemical Engineering,Nanjing University,Nanjing 210093,China 2 School of Chemistry and Chemical Engineering,Huaiyin Normal University,Huai’an 221003,China 3 State Key Laboratory of Coordination Chemistry,Nanjing University,Nanjing 210093,China 4 Department of Chemistry and Biochemistry,Texas Tech University,Texas 79409-1061,USA
Aminohalogenation reaction of β-nitrostyrenes with N-halosuccinimides(N-chloro and N-bromosuccinimides) has been successfully conducted by using nickel acetate as a catalyst in the presence of potassium carbonate and succinimide as co-additives.The reaction was easily performed at room temperature under nitrogen gas protection to give dihalorinaed haloamino products in good to excellent yields(60%-98%).The structure has been confirmed by X-ray crystal structure analysis.
ZHI SanJun1,2,SUN Hao2,LIN Chen2,ZHANG GuangQian2,LI GuiGen4 & PAN Yi2,3 1 Department of Chemistry,Huaiyin Normal University,Huai’an 221003,China
An efficient direct asymmetric aldol reaction with zinc triflate and prolinamides as combined catalysts is reported.A series of chiral prolinamides have been designed and used in the direct aldol reaction resulting in the desired products with excellent yields(up to 94% yield) and high enantioselectivities(up to 96% ee).Water was found to play a significant role in the formation of the aldol products,which suggests a new strategy in the design of new organic catalysts.
LU ZhiJin1,MEI HaiBo1,ZHANG GuangQian1,HAN JianLin1* & PAN Yi1,2* 1School of Chemistry and Chemical Engineering,Nanjing University,Nanjing 210093,China 2State Key Laboratory of Coordination Chemistry
