Highly Enantioselective Transfer Hydrogenation of Prochiral Ketones Using Ru(II)-Chitosan Catalyst in Aqueous Media
作者:György Szőllősi、Vanessza Judit Kolcsár
DOI:10.1002/cctc.201801602
日期:2019.1.23
Unprecedentedly high enantioselectivities are obtained in the transferhydrogenation of prochiral ketones catalyzed by a Ru complex formed in situ with chitosan chiral ligand. This biocompatible, biodegradable chiral polymer obtained from the natural chitin afforded good, up to 86 % enantioselectivities, in the aqueous‐phase transferhydrogenation of acetophenone derivatives using HCOONa as hydrogen donor. Cyclic
在与壳聚糖手性配体原位形成的Ru络合物催化的前手性酮的转移氢化中,获得了前所未有的高对映选择性。这种从天然几丁质中获得的生物相容性,可生物降解的手性聚合物,在使用HCOONa作为氢供体的苯乙酮衍生物的水相转移氢化中,提供了高达86%的良好对映选择性。环酮的对映选择性更高,超过90%,而在杂环酮的转移氢化中,进一步增加,最高可达97%。手性催化剂前体制备易地通过扫描电子显微镜,FT-中期和-far-IR光谱法检测。原位结构通过1 H NMR光谱和使用各种壳聚糖衍生物研究了形成的催化剂。结果表明,Ru预催化剂是通过氨基将生物聚合物与金属配位而形成的。加入氢供体后,该前体转化为水不溶性钌氢化物络合物。通过以高收率和光学纯度制备二十多种手性醇,验证了所开发方法的实用价值。在单次结晶后,将催化剂用于以克为单位获得光学纯的手性醇。
Synthesis and Reactivity of 2-Aminoethanethiolato-Bridged Dinuclear Ru(hmb) Complexes (hmb = η<sup>6</sup>-hexamethylbenzene): Mechanistic Consideration on Transfer Hydrogenation with Bifunctional [RuCl<sub>2</sub>(hmb)]<sub>2</sub>/2-Aminoethanethiol Catalyst System
enantioselectivity for the asymmetrictransferhydrogenation of aromatic ketones using HCO2H−N(C2H5)3. In agreement with these results, the crossover experiment using a symmetrically bridged dinuclear complex, [Ru(μ-SCH2CH2NH2)(hmb)]2Cl2, and its Cp*Ir dinuclear congener, [Cp*Ir(μ-SCH2CH2NH2)]2Cl2 (Cp* = η5-C5(CH3)5), suggested that the catalytic performance in the hydrogentransfer is originated from the
Ru-catalyzed mechanochemical asymmetric transfer hydrogenations in aqueous media using chitosan as chirality source
作者:Vanessza Judit Kolcsár、György Szőllősi
DOI:10.1016/j.mcat.2022.112162
日期:2022.3
energy transmission. Chitosan is a chiral biopolymer of natural origin, which can be used in asymmetric catalysis. The application of Ru-chitosan complexes along with the mechanochemical activation may open great opportunities for sustainable preparation of optically pure alcohols. In the present study, we optimized the mechanochemical asymmetrictransferhydrogenation of 4-chromanone, carried out in