Oligophosphan-Liganden, XXXVIII / Oligophosphine Ligands, XXXVIII

Abstract

Intermolecular activation of carbon-hydrogen bonds has been accomplished by reduction with sodium amalgam of (sip3)(Me3P)RuCl2, 1, [“sip3” = MeSi(CH2PMe)2)3] in aromatic hydrocarbons, such as benzene and substituted derivatives thereof. In these reactions, the 16e equivalent (sip3XMe3P)Ru(O) thus generated exhibits a preference for insertion across the unhindered metaand para-C-H bonds to produce complexes of composition (sip3)(Me3P)RuH(C6H3RR′) [R = R′ = H, 2; R = H, R′ = CH3, 3; R = R′ = CH3 (3,4-xylyl), 4; R = R′ = CH3 (3,5-xylyl), 5; R = H, R′ = CF3, 6], of which 3, 4, and 6 were isolated as mixtures of meta/para-isomers and Ru-aryl rotamers, respectively. Reaction of the phenyl hydride 2 with 4-MeC6H4NCE (E = O, S) leads to insertion of the heteroallenes into the Ru-Η bond to give (sip3)(Me3P)Ru[N(C6H4Me-4)C(O)H]C6H5, 8, and (sip3)(Me3P)Ru[SC(=NC6H4Me-4)H]C6H5, 10, as the primary products. While the latter forms (sip3) , 11, by loss of PMe3, the former reacts with another molecule of isocyanate to afford the acyl compound (sip3) 9, as the ultimate product. Treatment of 2 with CO2 results in the formation of a carbonato derivative, (sip3)(Me3P)Ru(O2CO), 7. •