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A chiral (mesitylene)RuCl(monosulfonated diamine) catalysed dynamic kinetic resolution (DKR)–asymmetric transfer hydrogenation (ATH) process is developed for highly enantio- (up to 99% ee) and diastereo- (up to 98 : 2 dr) selective reduction of challenging racemic α-aryl-γ-keto malononitriles. A spontaneous cyclization reaction of the hydrogenation products delivers a cascade process for efficient synthesis of useful enantioenriched 3,4-dihydro-2H-pyran-carbonitriles. [ABSTRACT FROM AUTHOR]

In an enantioselective reaction, we expect to obtain two types of chiral products through a controllable strategy in asymmetric catalysis. Herein, we develop Ru-catalysed asymmetric transfer hydrogenation of α-ketoimides to realise an enantioselective construction of chiral α-hydroxy imides or chiral α-hydroxy esters. The transformation of α-ketoimides catalysed by ( S, S)-[RuCl(η6-mesitylene)diamine] can afford various chiral α-hydroxy imides with high yields and enantioselectivities, whereas that catalysed by ( S, S)-[RuCl(η6-hexamethylbenzene)diamine] gives the desirable chiral α-hydroxy esters through a slight adjustment of the reaction conditions. The method described here is a controllable organic transformation with sodium formate as a hydrogen source under mild reaction conditions, and the benefit of this transformation is that various chiral α-hydroxy imides or α-hydroxy esters can be obtained selectively from α-ketoimides. [ABSTRACT FROM AUTHOR]

An important challenge in asymmetric cascade reactions is solving the intrinsic incompatibility of two types of distinct organometallic complexes that participate in a one-pot reaction. Herein, we develop an organoruthenium-/organopalladium-bifunctionalized periodic mesoporous organosilica and realize one-pot cascade reactions of Ru-catalyzed asymmetric transfer hydrogenation and Pd-relay-catalyzed cross-coupling of haloacetophenones and arylboronic acids to various chiral biaryl alcohols, with quantitative conversions and up to 98 % enantioselectivity in an aqueous medium. This characteristics is attributed to the site-isolated, uniformly distributed, well-defined single-site palladium and ruthenium active species. Furthermore, the heterogeneous catalyst is conveniently recovered and reused repeatedly for eight times without loss of its catalytic activity, showing particular attractiveness for practicing organic transformation. [ABSTRACT FROM AUTHOR]

α-Ketoimides undergo transfer hydrogenation with sodium formate as hydrogen source in the presence of chiral ruthenium catalyst. [ABSTRACT FROM AUTHOR]

Review: 50 refs. [ABSTRACT FROM AUTHOR]

A mildtransformation in an aqueous medium for the one-pot synthesisof optically active β-hydroxy sulfones is described. The intermediatesof β-keto sulfones obtained via a nucleophilic substitutionreaction of α-bromoketones and sodium sulfinates in H2O/MeOH (1:3, v/v) at 50 °C were reduced through Ru-catalyzedasymmetric transfer hydrogenation in one-pot using HCOONa as a hydrogensource providing a variety of chiral β-hydroxy sulfones withhigh yields and excellent enantioselectivities. [ABSTRACT FROM AUTHOR]

The nucleophilic substitution reaction of α-bromoketones with sodium sulfinates followed by Ru-catalyzed asymmetric transfer hydrogenation using sodium formate as hydrogen source provides β-hydroxy sulfones in high yields and excellent enantioselectivities. [ABSTRACT FROM AUTHOR]