1443500-40-0

Upstream product

• 67-56-1 methanol 
• 1295649-40-9 [carbonylchlorohydrido{bis[2-(diphenylphosphinomethyl)ethyl]amino}ethylamino] ruthenium(II) 
• 1333-74-0 hydrogen 

Relevant academic research and scientific papers

On the Mechanism of the Ruthenium-catalyzed β-methylation of Alcohols with Methanol

Selective β-methylation of alcohols with methanol has been recently described using a catalytic system comprising the ruthenium pincer complex [RuH(CO)(BH4)(HN(C2H4PPh2)2)]-(Ru-MACHO-BH) 1 and alcoholate bases as co-catalysts. Here we present a detailed mechanistic analysis for the mono-methylation of 1-phenyl-propane-1-ol 2 a as prototypical example. Several experimentally observed intermediates were localized as stable minima on the DFT-derived energy surface of the entire reaction network. The ruthenium complex [Ru(H)2(CO)(HN(C2H4PPh2)2)] I was inferred as the active species catalyzing the de-hydrogenation/re-hydrogenation of substrates and intermediates (“hydrogen borrowing”). The hydrogen-bonded alcohol adduct of this complex was identified as the lowest lying intermediate (TDI). The C?C bond formation results from a base-catalyzed aldol reaction comprising the transition state with the highest energy (TDTS). Experimentally determined Gibbs free activation barriers of 26.1 kcal/mol and 26.0 kcal/mol in methanol and toluene as solvents, respectively, are reflected well by the computed energy span of the complex reaction network (29.2 kcal/mol).

Acceptorless dehydrogenative coupling of alcohols catalysed by ruthenium PNP complexes: Influence of catalyst structure and of hydrogen mass transfer

Base-free catalytic acceptorless dehydrogenative homo-coupling of alcohols to esters under neat conditions was investigated using a combined organometallic synthesis and kinetic modelling approach. The considered bifunctional ruthenium aliphatic PNP complexes are very active, affording TONs up to 15,000. Notably, gas mass transfer issues were identified, which allowed us to rationalize previous observations. Indeed, the reaction kinetics are limited by the rate of transfer from the liquid phase to the gas phase of the hydrogen co-produced in the reaction. Mechanistically speaking, this relates to the interconverting couple amido monohydride/amino bishydride. Overcoming this by switching into the chemical regime leads to an initial turnover frequency increase from about 2000 up to 6100?h?1. This has a significant impact when considering assessment of novel or reported catalytic systems in this type of reaction, as overlooking of these engineering aspects can be misleading.

Practical selective hydrogenation of α-fluorinated esters with bifunctional pincer-type ruthenium(II) catalysts leading to fluorinated alcohols or fluoral hemiacetals

Selective hydrogenation of fluorinated esters with pincer-type bifunctional catalysts RuHCl(CO)(dpa) 1a, trans-RuH2(CO)(dpa) 1b, and trans-RuCl2(CO)(dpa) 1c under mild conditions proceeds rapidly to give the corresponding fluorinated alcohols or hemiacetals in good to excellent yields. Under the optimized conditions, the hydrogenation of chiral (R)-2-fluoropropionate proceeds smoothly to give the corresponding chiral alcohol without any serious decrease of the ee value.