Delta2- and Delta3- Azaosmetine Complexes as Intermediates in the Stoichiometric Imination of Phenylacetylene with Oximes

Autores: Ricardo Castarlenas, Miguel A. Esteruelas y Enrique Oñate Ref. revista: Organometallics, 20, 2294-2302, (2001)

Complexes [Os{(E)-CHdCHPh}Cl(dNdCR2)(PiPr3)2][CF3SO3] [CR2 ) CMe2 (1), C(CH2)4CH2 (2)] react with carbon monoxide to give the ¢2-1,2-azaosmetine derivatives [OsCl(dCHCH(Ph)NdCR2}(CO)(PiPr3)2][CF3SO3] [CR2 ) CMe2 (3), C(CH2)4CH2 (4)], as a result of the coordination of carbon monoxide to the osmium atoms of 1 and 2 and the carbonnitrogen coupling between the styryl and azavinylidene ligands. The structure of 3 in the solid state has been determined by an X-ray diffraction study. Complexes 3 and 4 can be deprotonated with MeLi to give the ¢3-1,2-azaosmetine compounds Os{CHdC(Ph)NdCR2}Cl(CO)(PiPr3)2 [CR2 ) CMe2 (5), C(CH2)4CH2 (6)], which react with molecular hydrogen to afford the 2-aza-1,3-butadienes CH2dC(Ph)NdCR2 [CR2 ) CMe2 (7), C(CH2)4CH2 (8)] and OsH2(è2-H2)(CO)(PiPr3)2. The carbonylation of the cations of 3 and 4 leads to [Os{(Z)-CHd C(Ph)NHdCR2}Cl(CO)2(PiPr3)2]+ [CR2 ) CMe2 (9), C(CH2)4CH2 (10)]. The [BF4]- salts of 9 and 10 have been obtained by carbonylation of 5 and 6 and subsequent protonation of the resulting è1-azabutadiene intermediates Os{(Z)-CHdC(Ph)NdCR2}Cl(CO)2(PiPr3)2 [CR2 ) CMe2 (11), C(CH2)4CH2 (12)]. The structure of the [BF4]- salt of 10 in the solid state has also been determined by an X-ray diffraction study.