Manganese-Catalyzed Aromatic C–H Allylation of Ketones

Manganese-catalyzed aromatic C–H allylation of ketones is reported. The reaction proceeded in a monoselective allylation manner to provide various ortho C–H allylated ketones in high yields. With challenging allylic electrophiles bearing substituents at the α-, β-, or γ-position, excellent SN2′ regioselectivity was achieved under mild conditions (rt to 35 °C). Mechanistic studies revealed a possible turnover-limiting C–H bond cleavage step affording a five-membered manganacycle followed by reaction with allylic electrophiles to give the C–H allylation product.