Sahcylaldehyde metal complexes

The development of chiral hydrogen-bond donors that function as catalysts for enantioselective organic reactions has been the focus of innumerable studies over the past dozen years, detailed in hundreds of pubhcations. One of the earliest successes in this area was from the Jacobsen laboratory, realized in the course of screening a library of metal complexes of sahcylaldehyde imines as catalysts for... 

The metal coordination complexes of both sahcylaldehyde phenyhiydrazone (91) and sahcylaldoxime provide antioxidant (92) protection and uv stabihty to polyolefins (see Antioxidants). In addition, the imines resulting from the reaction of sahcylaldehyde and aromatic amines, eg, p- am in oph en o1 or a-naphthylamine, can be used at very low levels as heat stabiLizers (qv) in polyolefins (93). 

Figure 1 The stabihty of complexes of divalent transition metal cations. 1, Triethylenetetramine, NH2C2H4NHC2H4NHC2H4NH2 2, EDTA, ethylenediaminetetraacetic acid 3, diethylenetriamine, NH2C2H4NHC2H4NH2 4, norleucine, Me(CH2)3CH(NH2)C02H 5, 1,2,3-triaminopropane, NH2CH2CH(NH2)CH2NH2 6, ethylene-diamine, NH2C2H4NH2 7, sahcylaldehyde, 2-(HO)CgH4CHO 8, oxalic acid, HO2CCO2H. For norleucine, 4, the values for log 82 are plotted...

It has been known for many years that the rate of hydrolysis of a-amino add esters is enhanced by a variety of metal ions such as copper(II), nickel(Il), magnesium(II), manganese(II), cobalt(II) and zinc(II). Early studies showed that glycine ester hydrolysis can be promoted by a tridentate copper(II) complex coupled by coordination of the amino group and hydrolysis by external hydroxide ion (Scheme 88). 3 Also, bis(sahcylaldehyde)copper(II) promotes terminal hydrolysis of the tripeptide glycylglycylglydne (equation 73). In this case the iV-terminal dipeptide fragment... 

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