The Mechanism Study Of The Reactionof Bisketene And Imine

Because of the good reactive activity of the ketene group, ketene compounds as a kind of important intermediate have been paid extensive attention for a long time. And the bisketene which has two active ketene groups shows much better reactivity.As active intermediates, bisketenes can react with a lot of different compounds. Among them, the reactions of bisketenes and imines give two different kinds of products, which are dihydrogen oxazione compounds and bis(β-lactam) compounds. But the cyclization selectivity of this reaction was not clear. The cyclization selectivity of the reaction of bisketenes and imines was researched in this paper. This has important significance for the control and application of the reaction.To figure out the mechanism and selectivity of the reaction of bisketene and imine, the method of combining the experiment and the density functional theory calculation is used in this research. First, the reactions of the bis(acyl chloride)s with various carbon chains and imines were studied. Adipoyl chloride and pimeloyl chloride gave oxazinones after reactions with imines. While glutaryl chloride, suberoyl chloride and azelaoyl chloride gave bis(β-lactam)s. And the two products could be gained at the same time in the reaction of pimeloyl chloride and imines. Then the energy profiles of the reaction of adipoyl chloride and imine were studied through the density functional theory calculation. The calculation suggested:the formation of two products is competitive when bis(acyl chloride)s and imines react with triethylamine. The generation of dihydrogen oxazinones is affected by ring strain. Only the oxazione products of adipoyl chloride and pimeloyl chloride whose ring strain is small enough can be obtained. The [2+2] cyclization of ketene group and imine need more activation energy. Only oxazinones can be obtained when reactions are proceeding at room temperature. When the temperature is high enough, bis(P-lactam)s can form.Conclusion in this paper interprets the mechanism and selectivity of the reaction of bisketene and imine clearly. We also extends the application of this reaction, and increases the depth of biskektene’s basic researches.