Rhodium complex with unsymmetrical vicinal diamine ligand: excellent catalyst for asymmetric transfer hydrogenation of ketones
作者:Sudhindra H. Deshpande、Vaishali S. Shende、Savita K. Shingote、Debamitra Chakravarty、Vedavati G. Puranik、Raghunath V. Chaudhari、Ashutosh A. Kelkar
DOI:10.1039/c5ra08220j
日期:——
investigated. The reaction mixture is homogeneous in methanol unlike in water, where substrate and product are insoluble in water and form separate phase, sodium formate being soluble in water. The activity and enantioselectivity obtained for ATH of ketones using [Rh(Cp*)Cl2]2 and unsymmetrical vicinal diamine ligand as catalyst was comparable with the C2 symmetric benchmark ligands like TsDPEN ((1R,2R)-N-(p-tolylsulfonyl)-1
从便宜的起始原料如去氧麻黄碱合成了新的不对称邻位二胺配体,其胺和磺酰胺基团的区域和立体位置发生系统性变化。已经研究了使用过渡金属配合物和以甲酸钠为氢源的单甲苯磺酸化不对称邻位二胺配体的新衍生物在水中和甲醇中对芳族烷基酮的催化不对称转移加氢(ATH)。以优异的对映选择性(> 95%ee)和[Rh(Cp *)Cl 2 ] 2和配体4转化酮(> 95%)获得手性仲醇作为催化剂。与使用水作为溶剂相比,发现使用甲醇作为酮(以甲酸钠为氢源)进行ATH的溶剂时,对映选择性略高,并且发现与所有研究的酮均相符。与在水中不同,反应混合物在甲醇中是均相的,在水中,底物和产物不溶于水并形成分离的相,而甲酸钠则溶于水。的活性和对映选择性使用酮为ATH获得的[Rh(CP *)氯2 ] 2和不对称连位二胺配体作为催化剂是与可比较的C ^ 2点对称基准的配体等TsDPEN((1 - [R,2 - [R ) - ñ - (p-甲苯基磺酰基)-1