A one-pot synthesis of α,β-unsaturated esters from unactivated esters and aldehydes using strong bases, such as sodium alkoxide and potassium tert-butoxide, was reported. However, the ionic liquid (IL) catalyzed probase method for producing α,β-unsaturated esters was not reported until now. In this work, a series of ILs with fluoride anions were firstly prepared and used as catalysts in combination with the probase N,O-bis(trimethylsilyl) acetamide (BSA) for the α,β-unsaturated esters synthesis. This process could also be promoted through the introduction of another IL with Lewis acid sites. The yield and selectivity of the product could reach up to 84.2% and 95.0%, respectively, when [Bmim]F was used in combination with [Bmim]Cl/AlCl₃ (the molar fraction of AlCl₃ is 0.67). The mechanism investigation through GC-MS indicates that BSA would convert into onium amide, which acted as a strong base for α-H abstraction, with the catalysis of [Bmim]F. Meanwhile, [Bmim]Cl/AlCl₃ played an important role in the condensation step between enolates and aldehydes. On the basis of mechanism insights, kinetic and thermodynamic studies were also carried out for a better understanding of this new route.

中文翻译：

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离子液体催化的Probase方法在温和条件下从酯和醛一锅合成α，β-不饱和酯

据报道，使用强碱（如醇钠和叔丁醇钾）从未活化的酯和醛进行一锅法合成α，β-不饱和酯。然而，迄今为止，尚未报道离子液体（IL）催化的脯氨酸制备α，β-不饱和酯的方法。在这项工作中，首先制备了一系列带有氟阴离子的ILs，并与Probase N，O-双（三甲基甲硅烷基）乙酰胺（BSA）结合用作催化剂，用于合成α，β-不饱和酯。也可以通过引入另一个带有路易斯酸位点的IL来促进这一过程。当[Bmim] F与[Bmim] Cl / AlCl ₃结合使用时，产物的收率和选择性分别达到84.2％和95.0％。（AlCl ₃的摩尔分数为0.67）。通过GC-MS进行的机理研究表明，BSA会在[Bmim] F的催化下转化成酰胺，成为α-H提取的强碱。同时，[Bmim] Cl / AlCl ₃在烯醇盐和醛之间的缩合步骤中起重要作用。在机理研究的基础上，还进行了动力学和热力学研究，以更好地理解这一新途径。