The fluorine-containing trans-l,2-cyclopropane derivatives 4ba--4dd were synthesized from the fluorine-containing electron-deficient alkenes 3a--3d with semistabilized arsonium ylides 2b--2d, in biphasic system of dic...The fluorine-containing trans-l,2-cyclopropane derivatives 4ba--4dd were synthesized from the fluorine-containing electron-deficient alkenes 3a--3d with semistabilized arsonium ylides 2b--2d, in biphasic system of dichloromethane-50% aqueous sodium hydroxide, generated in situ from the corresponding arsonium salts 1b-1d at room temperature in good yields with high stereoselectivity. The structure of fluorine-containing trans-1,2-cyclopropane derivatives were also studied.展开更多
In the presence of KF·2H2O, furoylmethyltriphenylarsonium bromide （1a） or thienoylmethyltriphenylarsonium bromide （1b） reacted with 2-[（un）substituted benzylidene]malononitrile （2） in chloroform at room t...In the presence of KF·2H2O, furoylmethyltriphenylarsonium bromide （1a） or thienoylmethyltriphenylarsonium bromide （1b） reacted with 2-[（un）substituted benzylidene]malononitrile （2） in chloroform at room temperature to give trans-3,3-dicyano-1-furoyl-2-[（un）substituted phenyl]cyclopropane （3a） or trans-3,3-dicyano-1-thienoyl-2- [（un）substituted phenyl]cyclopropane （3b） respectively in good yield with high stereoselectivity. The structures of product 3 were confirmed by IR, MS, 1^H NMR, 1^H-1^H COSY and microanalysis. The relative configuration of product 3 was determined by 1^H-1^H NOESY technique. The mechanism for the formation of product 3 was also proposed.展开更多
Multi-substituted dihydrofurans are valuable intermediates for the synthesis of natural products and pharmaceuticals. Considerable attention has been focused on the development of efficient and regioselective methods ...Multi-substituted dihydrofurans are valuable intermediates for the synthesis of natural products and pharmaceuticals. Considerable attention has been focused on the development of efficient and regioselective methods for their preparation. Using K2CO3 as a base, with the reaction of fur-2-oylmethyltriphenylarsonium bromide 1 and ethyl 2-acetyl-3-arylacrylate 2 in tetrahydrofuran at room temperature, we found an efficient protocol was achieved to synthesize trans-3-aryl-4-carbethoxy-2,3-dihydro-2-fur-2＇-oyl-5-methylfurans 3 in good yield with high stereoselectivity. The structure of compound 3 was confirmed by IR, ^1H NMR, MS and HRMS. The mechanism for the formation of 3 was proposed.展开更多
基金Project supported by the the National Natural Science Foundation of China （Nos. 20872086 and 20872088）, and the Project of Shanghai Municipal Education Commission （Nos. 09YZ19 and J50102）.
文摘The fluorine-containing trans-l,2-cyclopropane derivatives 4ba--4dd were synthesized from the fluorine-containing electron-deficient alkenes 3a--3d with semistabilized arsonium ylides 2b--2d, in biphasic system of dichloromethane-50% aqueous sodium hydroxide, generated in situ from the corresponding arsonium salts 1b-1d at room temperature in good yields with high stereoselectivity. The structure of fluorine-containing trans-1,2-cyclopropane derivatives were also studied.
基金Project supported by the National Natural Science Foundation of China （No. 20472047）, the Natural Science Foundation of Shanghai （No. 04ZR14060） and the Education Commission of Shanghai Municipality （Nos. 05AX12 and B.99-0303-06-034）.
文摘In the presence of KF·2H2O, furoylmethyltriphenylarsonium bromide （1a） or thienoylmethyltriphenylarsonium bromide （1b） reacted with 2-[（un）substituted benzylidene]malononitrile （2） in chloroform at room temperature to give trans-3,3-dicyano-1-furoyl-2-[（un）substituted phenyl]cyclopropane （3a） or trans-3,3-dicyano-1-thienoyl-2- [（un）substituted phenyl]cyclopropane （3b） respectively in good yield with high stereoselectivity. The structures of product 3 were confirmed by IR, MS, 1^H NMR, 1^H-1^H COSY and microanalysis. The relative configuration of product 3 was determined by 1^H-1^H NOESY technique. The mechanism for the formation of product 3 was also proposed.
基金Project supported by the National Natural Science Foundation of China （No. 20472047）, the Natural Science Foundation of Shanghai （No 04ZR14060） and the Education Commission of Shanghai Municipality （Nos. 05AX12 and B.99-0303-06-034）.
文摘Multi-substituted dihydrofurans are valuable intermediates for the synthesis of natural products and pharmaceuticals. Considerable attention has been focused on the development of efficient and regioselective methods for their preparation. Using K2CO3 as a base, with the reaction of fur-2-oylmethyltriphenylarsonium bromide 1 and ethyl 2-acetyl-3-arylacrylate 2 in tetrahydrofuran at room temperature, we found an efficient protocol was achieved to synthesize trans-3-aryl-4-carbethoxy-2,3-dihydro-2-fur-2＇-oyl-5-methylfurans 3 in good yield with high stereoselectivity. The structure of compound 3 was confirmed by IR, ^1H NMR, MS and HRMS. The mechanism for the formation of 3 was proposed.
