Reactions of RuClH(CO)(PPh3)3 with allylic amines: Insertions and an unusual carbon-nitrogen bond cleavage of allylic amines

Article abstract of DOI:10.1021/om00017a051

Reactions between RuClH(CO)(PPh₃)₃ and primary or secondary allylamines give olefin-insertion products: Ru(CH₂CH₂CH₂NHR)Cl(CO)(PPh₃) ₂ (R = H (1), CH₃ (4), and CH₂CH=CH₂ (5)). Analytical and spectroscopic studies on these products show they have an octahedral six-coordinate structure in which two triphenylphosphines are located mutually cis, and a phosphine-trans isomer is obtained only in the case of R = H. The insertion of the primary allylamine occurs after the initial ligand exchange of the allylamine with one PPh₃ of the starting complex. The variable-temperature NMR analyses reveal that the complexes derived from the secondary allylamines liberate one of the two PPh₃ ligands at high temperatures. When R = CH₃, an isolable dichloro-bridged dinuclear complex [Ru(μ-Cl)(CH₂CH₂CH₂NHCH ₃)(CO)-(PPh₃)]₂ (6) is formed by the liberation of PPh₃. A carbon-nitrogen bond of some tertiary allylic amines is cleaved in the reaction with RuClH(CO)(PPh₃)₃ to give the (π-allyl)ruthenium(II) complex Ru(η³-C₃H₅)Cl(CO)(PPh₃) ₂ (7) and its analog. The direct interaction between the Ru-H bond and the allylic amine leads to the formation of the (π-allyl)ruthenium(II) complex and the corresponding secondary amine without an increase of the oxidation state. Catalytic isomerization of some allylic amines to the enamines is also recognized during the insertion and the carbon - nitrogen bond cleavage.