Ruthenium-catalyzed coupling of aromatic carbon-hydrogen bonds in aromatic imidates with olefins

Catalytic C-H/olefin coupling can be directed by N,Oheterocyclic substituents. The Ru₃(CO)₁₂-catalyzed reaction of 4,4-dimethyl-2-(2-methylphenyl)-5,6-dihydro-4H-1,3-oxazine (1) with triethoxyvinylsilane gave a mixture of the corresponding 1:1 addition product (3a) and its olefinic analogue (3b) in good yields in ca. a 1:1 ratio. In the case of the reaction of 4,4-dimethyl-2-(2-methylphenyl)-4,5-dihydro-1,3-oxazole (7), the olefinic analogue (8b) of the coupling product (8a) was obtained as the major product. The existence of a new reaction pathway is discussed.