198478-54-5Relevant articles and documents
Reactivity of cyclomanganated 2-phenylpyridine derivatives toward organolithium reagents. Synthesis of novel chelated tricarbonyl(η3-benzyl)manganese(I) complexes
Djukic, Jean-Pierre,D?tz, Karl Heinz,Pfeffer, Michel,De Cian, André,Fischer, Jean
, p. 5171 - 5182 (2008/10/08)
Ortho-manganated 2-arylpyridine and -quinoline derivatives were treated with aryllithium reagents and subsequently with alkyl triflates to yield air-stable chelated (η3-benzyl)-tricarbonylmanganese complexes. Addition of PhLi to the cyclomanganated complex of 2-phenylpyridine [NC5H4-C6H4-Mn(CO)4], 1, followed by methylation with MeOTf afforded a red air-stable chelated η3-benzyl, tricarbonyl{2-[(1,2-η2),κC α-2-(phenylmethoxymethylene)-phenyl]pyridine- κN}manganese(I), complex 4a. The molecular structure of 4a was established by single-crystal X-ray diffraction analysis. The study of this structure indicates a helical shape in which the manganese center adopts an octahedral configuration. Spectroscopic analysis indicates that the addition of the aryllithium reagent to 1 generates a new temperature- and air-sensitive benzoylmanganate species. The latter and other anionic acylmanganese species generated from different substrates readily decompose above a temperature of 0 °C to yield ketones and a formal [Mn(CO)3]- species which is believed to remain coordinated to the ancilliary pyridinyl group. The latter anionic tricarbonylmanganese species was trapped by reaction with Me3SnCl and 2 equiv of PPh3 to yield a mixture of mer and fac isomers of Me3SnMn(CO)3(PPh3)2. The thermal decomposition of the benzoyl-manganates into ketones via a reductive elimination step was exploited as a new synthetic route of aromatic ketones bearing a pyridyl, quinolinyl, or benzo[h]quinolinyl substitution pattern.
