It was found that, when the Baylis-Hillman reaction of arylaldehydes withmethyl vinyl ketone was carried out at below - 20℃ in the presence of boron (Ⅲ) tribromide ortitanium (Ⅳ) bromide using a catalytic amount of...It was found that, when the Baylis-Hillman reaction of arylaldehydes withmethyl vinyl ketone was carried out at below - 20℃ in the presence of boron (Ⅲ) tribromide ortitanium (Ⅳ) bromide using a catalytic amount of Lewis base such as amine, the brominated compoundsand the Baylis-Hillman adducts could be obtained as the major products in good yields for variousaryl aldehydes. But at room temperature, the elimination products were the major products. Inaddition, the palladium catalyzed allylic substitution reactions of the e-limination products werealso examined.展开更多
A novel catalyst indium(Ⅲ) tribromide is shown to efficiently promote 5-carbonyl-4-aryl-3,4-dihydropyrimidin-2(1H)-ones from a three-component coupling of β-diketones, aldehydes and urea in ethanol. This modified on...A novel catalyst indium(Ⅲ) tribromide is shown to efficiently promote 5-carbonyl-4-aryl-3,4-dihydropyrimidin-2(1H)-ones from a three-component coupling of β-diketones, aldehydes and urea in ethanol. This modified one-pot Biginelli′s cyclocondensation not only features simple operation, but also takes place in nonpolluted environment. The structure of the Biginelli reaction product from β-diketones, salicylaldehyde and urea has been proposed to possess an oxygen-bridge.展开更多
文摘It was found that, when the Baylis-Hillman reaction of arylaldehydes withmethyl vinyl ketone was carried out at below - 20℃ in the presence of boron (Ⅲ) tribromide ortitanium (Ⅳ) bromide using a catalytic amount of Lewis base such as amine, the brominated compoundsand the Baylis-Hillman adducts could be obtained as the major products in good yields for variousaryl aldehydes. But at room temperature, the elimination products were the major products. Inaddition, the palladium catalyzed allylic substitution reactions of the e-limination products werealso examined.
文摘A novel catalyst indium(Ⅲ) tribromide is shown to efficiently promote 5-carbonyl-4-aryl-3,4-dihydropyrimidin-2(1H)-ones from a three-component coupling of β-diketones, aldehydes and urea in ethanol. This modified one-pot Biginelli′s cyclocondensation not only features simple operation, but also takes place in nonpolluted environment. The structure of the Biginelli reaction product from β-diketones, salicylaldehyde and urea has been proposed to possess an oxygen-bridge.
