Ru-TsDPEN

Preparation of polymer-supported ru-tsdpen catalysts and their use... 

Ru-TsDPEN CATALYZED TRANSFER HYDROGENATION REACTION OF S,y-UNSATURATED-a-KETOESTERS... 

Table 3.8 Ru-TsDPEN catalyzed transfer hydrogenation reaction of /i,y-unsaturated-a- ...

PREPARATION OF POLYMER-SUPPORTED RU-TSDPEN CATALYSTS AND THEIR USE FOR ENANTIOSELECTIVE SYNTHESIS OF (5)-FLUOXETlNE... 

As the transfer hydrogenation reactions using Ru-TsDPEN catalyst could take place in aqueous solution [108-111], the next stage was to develop a polymeric catalyst suitable for the aqueous conditions. One such example was the use of PEG as a polymer support, as reported by Xiao [112]. The PEG-supported TsDPEN 176 (Scheme 3.54) was highly effective in the Ru(II)-catalyzed transfer hydrogenation of simple ketones by sodium formate in water. The same polymeric catalyst was also effective for the same reaction by using a formic acid-triethylamine azeotrope [113]. 

The above catalytic systems for the asymmetric hydrogenation of quinolines are mainly iridium catalysts. In 2008, Fan and coworkers developed recyclable phos phine free chiral cationic ruthenium catalyzed asymmetric hydrogenation of qui nolines [23]. They found that the phosphine free cationic Ru/TsDPEN catalyst exhibited unprecedented reactivity and high enantioselectivity in the hydrogenation of quinolines in neat ionic liquid. The results were very excellent and enantioselec... 

The high enantioselectivity in the hydrogenation of ketones to chiral secondary alcohols, achieved by using chiral diphosphines and amine-based Ru complexes under neutral to slightly basic conditions, was reviewed. The high reactivity was attributed to a concerted six-membered transition state. The j -arene/TsDPEN-Ru (TsDPEN = A -(p-toluenesulfonyl)-l,2-diphenylethylenediamine) and MsDPEN-Cp Ir catalysts affected the asymmetric reaction under slightly acidic conditions. ... 

Another magnetically recoverable catalytic silica microreactors 156 were prepared and tested in the ATH of ketones in aqueous medium [135]. Magnetite nanoparticles were coated with shells synthesised via co-polymerisation of Si(OEt)4 and the Ru-TsDPEN complex 157 functionalised with a trimethoxysilane group. The transport of the hydrophobic reactants from the water medium to an entrapped catalyst in a sol-gel matrix was ensured by the surfactant CTAC. Under these conditions, ring-substituted acetophenones were almost quantitatively reduced with HC02Na giving the corresponding alcohols in over 90 % ees within 24 h (Fig. 49). 

Fig. 1 Asymmetric transfer hydrogenation of imines using Ru/TsDPEN complexes...

Zhang, J. Blazecka, P. G. Bruendl, M. M. Huang, Y. Ru-TsDPEN with formic acid/Hunig s base for asymmetric transfer hydrogenation, a practical synthesis of optically enriched N-propyl pantolactam. /. Org. Chem. 2009, 74, 1411-1414. 

RuH(Tsdpen)(u°-arene) Cp MH(Tsdpen) tethered arene Ru(Tsdpen) tethered Cp M(Tsdpen)... 

PNU-142721, a potent anft-HIV medicine. Wills reported that his tethered version of the Ru(TsDPEN) catalyst is also highly effective for asymmetric reduction of 2,6-diacetylpyridine with a mixture of HC02H/N(C2H5)3 to a chiral diol with 99.6% ee in 91% yield [36]. 

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