An effective route to cycloruthenated N-ligands under mild conditions

Cycloruthenated complexes of the type [(eta(6)-C6H6)Ru(C boolean AND N)CH3CN]+PF6- (C boolean AND N = C6H4-2-CH2NMe2, (R)-(+)-C6H4-2-CH(Me)NMe2, C6H2-3, 4-(OCH3)(2)-2-CH2NMe2) are readily obtained by the intramolecular C-H activation of N,N-dimethylbenzylamine derivatives with [(eta(6)-C6H6)RuCl2](2) in up to 53% isolated yields. Under similar conditions, 8-methylquinoline also Led to a cycloruthenated complex, though in, lower yield (12%) and after a longer reaction, time. Reaction with the optically active (R)-(+)-N,N-dimethyl-1-phenylethylamine led to a 48% diastereomeric excess in the cycloruthenated product. Under the same conditions, and after 14 and 65 h of reaction time, respectively, 2-phenyl- and 2-benzylpyridine are cyclometalated, leading to the formation of complexes in which the benzene ligand has been substituted by three acetonitriles: [(C boolean AND N)Ru(CH3CN)(4)]+PF6- (C boolean AND N = C6H4-2-C5H4N, C6H4-2-(CH2)-C5H4N) were obtained in. 40 and 24% isolated yields, respectively.