Ortho-manganated 2-arylpyridine and -quinoline derivatives were treate
d with aryllithium reagents and subsequently with alkyl triflates to y
ield air-stable chelated (eta(3)-benzyl)-tricarbonylmanganese complexe
s. Addition of PhLi to the cyclomanganated complex of 2-phenylpyridine
[NC5H4-C6H4-Mn(CO)(4)], 1, followed by methylation with MeOTf afforde
d a red air-stable chelated eta(3)-benzyl, tricarbonyl{2-[(1,2-eta(2))
,kappa -alpha-2-(phenylmethoxymethylene)-phenyl]pyridine- kappa N}mang
anese(I), complex 4a. The molecular structure of lia was established b
y single-crystal X-ray diffraction analysis. The study of this structu
re indicates a helical shape in which the manganese center adopts an o
ctahedral configuration. Spectroscopic analysis indicates that the add
ition of the aryllithium reagent to 1 generates a new temperature-and
air-sensitive benzoylmanganate species. The latter and other anionic a
cylmanganese species generated from different substrates readily decom
pose above a temperature of 0 degrees 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 sp
ecies was trapped by reaction with Me3SnCl and 2 equiv of PPh3 to yiel
d a mixture of mer and fac isomers of Me3SnMn(CO)(3)(PPh3)(2). The the
rmal decomposition of the benzoylmanganates into ketones via a reducti
ve elimination step was exploited as a new synthetic route of aromatic
ketones bearing a pyridyl, quinolinyl, or benzo[h]quinolinyl substitu
tion pattern.