Bipyridines, bridged, chirality

Kanomata N, Suzuki J, Kubota H, Nishimura K, Enomoto T (2009) Synthesis of planar-chiral bridged bipyridines and terpyridines by metal-mediated coupling reactions of pyridinophanes. Tetrahedron Lett 50 2740-2743... 

The similar ruthenium(II) complex, [Ru(S( — )-PhEtbpy)3]2+ ((S( — )-PhEtbpy = 4,4 -bis[(S)-( — )-l-phenylethylaminocarbonyl]-2,2 -bipyridine), was synthesized by the same authors [27]. In this complex, chiral phenethylamine is introduced into 2,2 -bipyridine through the amido bridge (see Scheme 8C). This complex was also applied to stereoselective photoreduction of Co(acac)3. In this reaction, the stereoselectivity is reverse to that observed in the reaction by [Ru(( — )-men-... 

Use of the chiral iron catalyst 28 for asymmetric sulfide oxidation was recently reported by Fontecave [48]. The complex is a dimer with two iron centers which are connected via a r -oxo bridge. Two bidentate (-)-4,5-pinene-bipyridine hg-ands 29 and one molecule of water are coordinated to each iron atom thus completing the octahedral environment of this diferric complex. Complex 28 can be isolated as a green solid with four perchlorates as counterions. 

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