| 1,4-dicarbonyl compounds are common in nature and are also a valuable compound structure in the fields of agriculture,medicine,chemical industry and so on.In particular,1,4-dicarbonyl is an important structural unit for the synthesis of five-membered heterocyclic compounds such as furan,thiophene,pyrrole and cyclopentenone.In this paper,we investigated the effects of ?,?-diarylene allyl alcohol and benzaldehyde on the condensation reaction under no metal catalysis to obtain 1,4-dicarbonyl compounds.1.In this paper,?,?-diaryl-allyl alcohol as the substrate,TBPB(tert-butyl benzoate)as a green oxidant,benzaldehyde is a cheap and easy acylation reagent,toluene as the reaction solvent,The reaction was carried out at 120 oC for 24 hours to give 1,4-dicarbonyl compounds in 94% yield.The novel is that there is no need for substrate modification,no strong acid or base participation,and it has the advantages of simple operation,efficient,environmentally friendly,and there is no surplus by-product,the atomic economic effect is outstanding.(?)2.In order to elucidate reaction mechanism,a comparative test was designed.The results showed that the presence of ?,?-diarylene allyl alcohol and benzaldehyde did not detect the presence of the corresponding target product without adding TBPB.The smooth progress of the reaction plays a key role.And under the standard conditions,2 equiv of the free radical scavenger,TEMPO(2,2,6,6-tetramethylpiperidine-nitrogen oxide),was added to the reaction system without obtaining the desired product,indicating that there might be presence of free radicals in the reaction.According to the comparison experiment and the publishedliterature,the possible reaction mechanism is deduced:(?)... |
PDF Full Text Request