BINAP-RuCL complexes

Fig. 1. P MAS NMR spectrum of (a)Ru-BrNAP/PTA/y-Al203, and (b)Ru-BINAP crt rlex In order to find the characteristics of the immobilized catalyst, asymmetric hydrogenation of the prochiral C=C bond was performed as a model reaction. Firstly, three different homogeneous Ru-BINAP complexes including [RuCl2((R)-BINAP)], [RuCl((R)-BINAP)(p-cymene)]Cl and [RuCl((R)-BINAP)(Benzene)]Cl were immobilized on the PTA-modified alumina. Reaction test of immobilized catalysts showed that [RuCl2((R)-BINAP)] was the most active and selective so all the experiment were done using this catalyst afterwards.

CH2CI2 occurs 9.8-fold faster than that of the S isomer, and the equilibration between the enantiomeric substrates is 4.4-fold faster than hydrogenation of the slow-reacting S substrate. On the other hand, hydrogenation of racemic 3-acetyltetrahy-drofuran-2-one catalyzed by the cationic (l )-BINAP-RuCl()7 -C6H6) complex gives the 3S,ri syn) alcohol in up to 97% e.e. (Eq. 2.22) [120, 158bj. A similar result is obtained by use of a tetraMe-BITIANP-Ru complex [49]. 

The decrease in the dihedral angle of the biaryl backbone had a profound effect on both reactivity and enantioselectivity. It was determined that the catalyst [NH2Me2]+ (RuCl(/ -ScgPIIOS) 2(Li-Cl)3] can hydrogenate 2-oxo-l-propanol to (2R)- 1,2-propanediol in 98.5% ee and with an S/C ratio of 10,000. (2R)- 1,2-propanediol is used in the production of Levofloxacin (see Section 12.2.2.5). The current catalyst used in production is a R-Tol-BINAP-Ru(II) complex.130... 

Asymmetric lactonization of prochiral diols has been performed vsdth chiral phosphine complex catalysts (Ru2Cl4((-)-DIOP)3 and [RuCl((S)-BINAP)(QH6)]Cl [17, 18]. Kinetic resolution of racemic secondary alcohol was also carried out with chiral ruthenium complexes 7 and 8 in the presence of a hydrogen acceptor, and optically active secondary alcohols were obtained with >99% e.e. (Eqs. 3.7 and 3.8) [19, 20]. 

Ruthenium(binap) complexes effectively catalyze asymmetric hydrogenation of a-amidocinnamic acids [172], allylic alcohols [173] and acrylic acids with almost quantitative enantiomeric excess [174]. For example, one of the largest-selling anti-inflammatory agents, Naproxen should be supplied as the enantiomerically pure 5-isomer, because the R-isomer is expected to be toxic to the liver. Asymmetric hydrogenation of the precursor by RuCL[(5)- binap] produces 5-Naproxen with 96-98 % ee (eq (47)) [175-176]. 

An anionic dinuclear BINAP-ruthenium(ll) complex crystal structure of [NH2Et2][ RuCl((R)-p-MeO-BlNAP) 2 (p,-Cl)3] and its use in asymmetric hydrogenation. Ohta T, Tonomura Y, Nozaki K, Takaya H, Mashima K. Organome-tallics 1996 15(6) 1521-1523. 

The phosphine (127)-catalysed asymmetric 4 +1-cycloaddition reaction of Morita-Baylis-Hillman carbonates with dicyano-2-methylenebut-3-enoates formed highly functionalized cyclopentenes in high yields and excellent ee% The [RuCl(CO)2]2-catalysed 4 + 1-cycloaddition reaction of alkenyl propargyl acetates, RCH(OAc)C=CC(Me)=CH2, with CO in CH2CI2 produced highly functionalized cyclopentenones in high yields (96%). The chiral copper/Tol-BINAP complex... 

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