RuCl2 -binap

Asymmetric hydrogenation of -oxo estersf The preferred catalyst for this reaction is RuCl2[BINAP], prepared by reaction of Ru(OAc)2[BINAP], with HC1 (2 equiv.). Details for the preparation of the catalyst and use in asymmetric hydrogena-... 

Asymmetric hydrogenation of proprietary P-keto esters with [RuCl2(BINAP)]n in 98-99% ee had been performed by NSC Technologies (Scheme 12.13). Substrate-to-catalyst loadings of 10,000-20,000 have been achieved. These reductions have been performed at small-scale production to ton scale.23 Phoenix Chemicals, whose specialty is in continuous processes, has developed methodology and equipment that can perform this type of transformation up to -100 tons/year for a proprietary P-hydro ester with enantioselectivities of 98-99% ee (see Chapter 31).6768... 

Except for unsaturated residues R, p-hydroxy esters (4) of excellent optical purity can also be obtained by enantioselective hydrogenation of the corresponding p-keto esters catalyzed by RuCl2(BINAP).i ... 

To hydrogenate prochiral ketones to the corresponding chiral alcohols, Noyori et al. have developed ternary catalyst systems from [RuCl2(binap)(dmf) ], a chiral diamine, and KOH. [13, 14] By this route methyl(l-naph-thyl)ketone can be hydrogenated to l-(l-naph-thyl)ethanol with [RuCl2(binap)(dmf) ], 1,2-diphenylethyldiamine, and KOH in the ratio 1 1 2 in isopropanol (substrate catalyst = 500 1, 4 bar H2, 28 °C, 6 h) in greater than 99 % yield with 97 % ee. 

The application of dynamic kinetic discrimination to the ruthenium-catalysed hydrogenation of cyclic ketones such as 2-arylated cycloalkanones was reported by Noyori s group in 2004. Hence, the asymmetric hydrogenation of various 2-arylcycloalkanones with tra s -RuCl2(BINAP)(l, 2-diamine) and t-BuOK in ijo-propyl alcohol selectively gave the corresponding cis-2-arylcycloalkanols in excellent enantiomeric purity and quantitative yield, as shown in Scheme 2.25. 

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