Deep eutectic solvents as H2-sources for Ru(II)-catalyzed transfer hydrogenation of carbonyl compounds under mild conditions
作者:Marzia Cavallo、Davide Arnodo、Alberto Mannu、Marco Blangetti、Cristina Prandi、Walter Baratta、Salvatore Baldino
DOI:10.1016/j.tet.2021.131997
日期:2021.3
affordable ruthenium(II)-complexes as pre-catalysts in the transfer hydrogenation of carbonyl compounds in deep eutectic media is described for the first time. The eutectic mixture tetrabutylammonium bromide/formic acid = 1/1 (TBABr/HCOOH = 1/1) acts both as reaction medium and hydrogen source. The addition of a base is required for the process to occur. An extensive optimization of the reaction conditions has
首次描述了在深度共晶介质中羰基化合物转移加氢中使用廉价的钌(II)络合物作为预催化剂的方法。低共熔混合物四丁基溴化铵/甲酸= 1/1(TBABr / HCOOH = 1/1)既充当反应介质,又充当氢源。要进行该过程,需要添加碱。在催化剂负载量,配合物类型,H 2-给体,反应温度和时间方面,已经对反应条件进行了广泛的优化。二聚体复合物[RuCl(p- Cymene)-μ- Cl] 2的组合(0.01–0.05当量)和配体dppf(1,1'-二茂铁基-双(二苯基膦)二茂铁)的摩尔比为1/1,已被证明是一种适合的催化体系,可将多种醛和酮还原为在空气中温和条件(40–60°C)下,其相应的醇显示出对不同官能团(卤素,氰基,硝基,苯酚)的中等至极好的耐受性。还研究了亚胺化合物还原成其相应的胺衍生物。此外,在TBABr / HCOOH和有机溶剂中获得的结果之间的比较表明,在此过程中,DES介质具有无害的作用。