Schifls bases

Daul, C., Schlapfer, C. W., von Zelewsky, A. The Electronic Structure of Cobalt (II) Complexes with Schifl Bases and Related Ligands. Vol. 36, pp. 129—171. 

Irradiation of 1 in moist acetonitrile containing triethylamine leads to no net reduction of the Ru(II) complex addition of water to solutions of reduced 1 in acetonitrile produce a rapid regeneration of the Ru(II) complex. While the products have not yet been determined, it is evident that a net redox reaction between water and the reduced ruthenium complex is occurring. Under these conditions (water, acetonitrile, and triethylamine), sustained irradiation of 1 can be carried out so that appreciable conversion of the triethylamine occurs acetaldehyde, which presumably arises through hydrolysis of the SchiflE base produced in Reaction 15, is easily detected by VPC as a major product. A trace of product having a retention time identical to succinonitrile is also detectable by VPC, but it appears that Reactions 14, 15, and 16 are the predominant paths for rapid depletion of the triethylamine radical cation. 

In another preliminary report the disulphide ligand (34) is shown to be quinquedentate in the cationic chloro-complex (35). One of the sulphur atoms is not co-ordinated to the nickel atom. The sexidentate Schifl-base... 

Enantioselective transfer hydrogenation (from propan-2-ol) of some ketones catalysed by iridium(i) complexes with chiral Schifl-base ligands has been reported, giving product alcohol of up to 33% e.e. with propiophenone as substrate. Other new reductive routes to chiral secondary alcohols involve the asymmetric hydrogenation of enol phosphinates (21) catalysed by chiral ferrocenyl-rhodium... 

A suggestion has been made that asymmetric induction is possible in cycloaddition reactions leading to azetidinones. The reaction of dimethylketene methyl-trimethylsilylacetal with the Schifl s bases of chiral a-aminoesters in the presence of titanium tetrachloride gave rise to the corresponding /3-lactams with extremely high stereoselectivity. The authors propose the formation of a template (183) between titanium and the Schiff s base leading to stereocontrol (Scheme 24). 

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