Synthesis of Pincer Ruthenium RuCl(CNN)(PP) Catalysts from [RuCl(μ-Cl)(η6-p-cymene)]2

Efficient transfer hydrogenation of ketones by molybdenum complexes through comprehensively verifying auxiliary ligands

Molybdenum complexes, ligated with N1,N1-dialkyl-N2-(5,6,7,8-tetrahydroquinolin-8-yl)ethane-1,2-diamines along with auxiliary ligands, provide various structural features as [NNH/NNHN]Mo(CO)4/3 (Mo1 – Mo3), [NNHN]Mo(CO)2Br] (Mo4 – Mo5), [NNH]Mo(CO)(η3-C3H5)Br](Mo6) and [NNHN/S] Mo(CO)(PPh3)2] (Mo7 – Mo8). All...

Transfer Hydrogenation from 2-propanol to Acetophenone Catalyzed by [RuCl2(η6-arene)P] (P = monophosphine) and [Rh(PP)2]X (PP = diphosphine, X = Cl−, BF4−) Complexes

The reduction of ketones through homogeneous transfer hydrogenation catalyzed by transition metals is one of the most important routes for obtaining alcohols from carbonyl compounds. The interest of this method increases when opportune catalytic precursors are able to perform the transformation in an asymmetric fashion, generating enantiomerically enriched chiral alcohols. This reaction has been extensively studied in terms of catalysts and variety of substrates. A large amount of information about the possible mechanisms is available nowadays, which has been of high importance for the development of systems with excellent outcomes in terms of conversion, enantioselectivity and Turn Over Frequency. On the other side, many mechanistic aspects are still unclear, especially for those catalytic precursors which have shown only moderate performances in transfer hydeogenation. This is the case of neutral [RuCl2(η6-arene)(P)] and cationic [Rh(PP)2]X (X = anion; P and PP = mono- and bidentate phosphine, respectively) complexes. Herein, a summary of the known information about the Transfer Hydrogenation catalyzed by these complexes is provided with a continuous focus on the more relevant mechanistic features.

An air and moisture tolerant iminotrihydroquinoline-ruthenium(ii) catalyst for the transfer hydrogenation of ketones

Both amine- and imine-containing E and F are highly effective in the transfer hydrogenation of a wide range of ketones with F significantly operating in bench quality 2-propanol and in vessels open to the air.

Asymmetric calixarene derivatives as potential hosts in chiral recognition processes

New chiral derivatives of 15,35,55,75-tetra-tert-butyl-1,3,5,7(1,3)-tetrabenzenacyclooctaphane-12,32,52,72-tetraol [(1); tert-butyl-calix[4]-arene] were synthesized by coupling modified chiral quinuclidines derived from the natural-product-based alkaloids quincorine and quincoridine with the calix[4]arene 1 via either an ester bond or an amide bond. X-ray analyses of two products were performed. Applications of the products in asymmetric catalytic hydrogen transfer reactions are described. A protocol is presented to multi-substitute calix[4]arene at the methylene bridges, resulting in, e.g., 2,6-carboxyl-all-tert-butyl all-methoxy-calix[4]arene.

1,2,3-Triazolylidene ruthenium(ii)(η6-arene) complexes: synthesis, metallation and reactivity

Three bis(1,2,3-triazolylidene) silver(i) complexes were reacted with [RuCl₂(p-cymene)]₂ and the ruthenium complexes [RCH₂N₂(NMe)C₂Ph]RuCl₂(p-cymene) (R = C₆H₂Me₃4a1, C₆H₂iPr₃4b1, Ph 4c1) were isolated as major products with the minor C(sp²)–H activated products [RCH₂N₂(NMe)C₂C₆H₄]RuCl(p-cymene) (R = C₆H₂Me₃4a2, C₆H₂iPr₃4b2, Ph 4c2) and [(C₆H₄)CH₂N₂(NMe)C₂Ph]RuCl(p-cymene) (4c3).