Ring-Opening Ortho-C-H Allylation of Benzoic Acids with Vinylcyclopropanes: Merging Catalytic C-H and C-C Activation Concepts.

A Ru-catalyzed selective and atom-economic ortho-C-H allylation of aromatic acids with vinylcyclopropanes is reported. The reaction proceeds with selective cleavage of both a C-H and a C-C bond. A wide range of allylarenes were synthesized in high yields and stereoselectivities. The vinylcyclopropane substrates can optionally be generated in situ from a diazo compound and 1,3-butadiene. Concise syntheses of isocoumarin and 3,4-dihydroisocoumarin derivatives underline the synthetic utility of the reaction.