Optical resolution amine metal complexes

Optical recording systems, 6, 126 Optical resolution amine metal complexes, 2,25 Oral contraceptives iron deficiency, 6, 764 Orbital angular momentum quenching, 1,262 /-Orbital systems... 

Odta — see Acetic acid, octamethylenediaminetetra-Optical resolution amine metal complexes, 25 Ore-forming solutions metal sulfides, 525 Organometallic complexes solubility... 

Preparative Methods racemic l,l -bi-2,2 -naphthol (BINOL) is most conveniently prepared by the oxidative coupling reaction of 2-naphthol in the presence of transition metal complexes (eq 1). The resolution of racemic BINOL with cinchonine may be performed via the cyclic phosphate (eq 2). An alternative procedure to provide directly optically active BINOL is the oxidative coupling of 2-naphthol catalyzed by Cu salt in the presence of chiral amines (eq 3). The best procedure uses (+)-amphetamine as the chiral ligand and provides BINOL in 98% yield and 96% ee. Above 25 °C the Cu /(+)-amphetamine/(5)-BINOL complex precipitates, while the more soluble Cu /(+)-amphetamine/(I )-BINOL complex is slowly transformed into the former complex. 9,9 -Biphenanthrene-10,10 -diol has also been prepared in 86% yield and with 98% ee by a similar asymmetric oxidative coupling of 9-phenanthrol in the presence of (I )- 1,2-diphenylethylamine. ... 

The atropisomeric dinaphthophosphepins ( )-(35) (R = Me, Ph) can be prepared from 2,2 -dimethyl-l,r-dinaphthyl by lithiation and addition of the respective dichlorophosphine <94TA5ll, 94JOC6363>. The resolutions of ( )-(35) (R = Me, Ph) were accomplished by the method of metal complexation with use of an optically active ortho-metallated palladium(II)-amine complex. The absolute configuration of (S)-(—)-(35) (R = Ph) was determined from the x-ray crystal structure of (36). The optically active phosphepin in conjunction with rhodium(I) is an effective auxiliary for the asymmetric hydroformylation of styrene. 

It has been demonstrated that the combination of metal-catalysed racemisation and enzymatic kinetic resolution is a powerful method for the synthesis of optically active compounds from racemic alcohols and amines. There are many metal complexes active for racemisation, but the conditions for enzymatic acylation often limit the application of the metal complexes to DKR. In the case of DKR of alcohols, complementary catalyst systems are now available for the synthesis of both (R)- and (5)-esters. Thus, (R)-esters can be obtained by the combination of an R-selective lipase, such as CAL-B or LPS, and a racemisation catalyst, whereas the use of an A-selective protease, such as subtilisin, at room temperature provides (5)-esters. The DKR of alcohols can be achieved not only for simple alcohols but also for those bearing various additional functional groups. The DKR of alcohols has also been applied to the synthesis of chiral polymers and coupled to tandem reactions, producing various polycyclic compounds. 

Coordination of ammonia or a substituted ammonia to a metal ion alters markedly the N — H dissociation rate (see See. 6.4.2). Since also proton dissoeiation of complexed ammines is base-catalyzed, then exchange can be made quite slow in an aeid medium. Thus, in a eoordinated system of the type 12, containing an asymmetric nitrogen atom (and this is the only potential souree of optical activity), there is every chance for a successful resolution in acid conditions, since inversion is expected only after deprotonation. It was not until 1966 that this was suc-eessfully performed, however, using the complex ion 12. A number of Co(III), Pt(II) and Pt(IV) complexes containing sarcosine or secondary amines have been resolved and their raeemizations studied.Asymmetrie nitrogen centers appear eonfined to d and d ... 

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