Ruthenium complexes amino

Other amino alcohols have also been used as chiral ligands in asymmetric catalytic hydrogen transfer. Scheme 6-54 depicts another example. Ruthenium complex bearing 2-azanorbornyl methanol was used as the chiral ligand, and the corresponding secondary alcohols were obtained in excellent ee.116... 

ATH with Ruthenium Complexes of Amino Alcohol Complexes Linked to the Primary Face of P-Cyclodextrin 48... 

Fig. 17. Noyori s ATH system using ruthenium complexes of chiral 1,2-amino alcohols 41 and monotosylated 1,2-diamines 42, respectively.

To improve the rate of reduction the amino alcohol ligand of the ruthenium complexes was exchanged for monotosylated 1,2-diamine ligands. For exploratory experiments AT-tosylethane-1,2-diamine was prepared hy monotosylation of ethane-1,2-diamine and attached to the primary face of P-CD yielding 80. With P-CD as the only chiral unit the ruthenium complex of 80 could reduce aromatic and aliphatic standard ketones 63 and 69 in 91% 5deld, 25% ee (S) and 68% 5deld, 58% ee, respectively, within only 4h under standard conditions (Fig. 24). 

Reactivity studies revealed that the ruthenium complexes of monotosylated 1,2-diamines linked to P-CD such as 80 react about three times faster than their amino alcohol counterparts. Several... 

Sinou and coworkers evaluated a range of enantiopure amino alcohols derived from tartaric acid for the ATH reduction of prochiral ketones. Various (2R,iR)-i-amino- and (alkylamino)-l,4-bis(benzyloxy)butan-2-ol were obtained from readily available (-I-)-diethyl tartrate. These enantiopure amino alcohols have been used with Ru(p-cymene)Cl2 or Ir(l) precursors as ligands in the hydrogen transfer reduction of various aryl alkyl ketones ee-values of up to 80% have been obtained using the ruthenium complex [93]. Using (2R,3R)-3-amino-l,4-bis(benzyloxy)butan-2-ol and (2R,3R)-3-(benzylamino)-l,4-bis(benzyloxy)butan-2-ol with [lr(cod)Cl]2 as precursor, the ATH of acetophenone resulted in a maximum yield of 72%, 30% ee, 3h, 25 °C in PrOH/KOH with the former, and 88% yield, 28% ee, 120 h with the latter. 

By introducing long alkyl side chains into the poly(p-phenylenevinylene) (PPV) backbones and to the amino groups on the NLO chromophores, a low-7), polymer X (Scheme 8) containing ruthenium complexes and a conjugated system is... 

Asymmetric hydrogen transfer shows promise for use at industrial scale because ruthenium complexes that contain chiral vicinal diamino 164 or amino alcohol 165 ligands allow the reductions of substrates such as aryl ketones and imines to be achieved under mild conditions.13 207... 

A fluorescent complex [Ru(r 6-p-cym)Cl(L)]Cl (L = 2-[(2-aminoethyl)amino] ethyl-2-(methylamino)benzoate) has been synthesised by tagging a small fluoro-genic reporter onto the chelating ligand. The interaction of this complex with porcine liver esterase (PLE) showed that esterase-catalysed hydrolysis reactions can liberate methylisatoic acid (MIAH) from the ruthenium complex suggesting a possible use of similar derivatives in esterase-activated Ru-based prodrug delivery systems. The hydrolysis reaction appears to be slow [156]. 

Ruthenium complexes have been used for the hydrogenation of alkenes but they had not been used for hydrogenations of carbonyl compounds until recently, when several highly selective catalytic hydrogenations of carbonyl compounds (P-keto esters, a-diketones, a-amino ketones etc., ee > 95%) were reported using BINAP-Ru" complexes (equation 18). ° ... 

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