Ruthenium-catalyzed oxidative coupling of vinylene carbonate with isoxazoles: access to fused anthranils.

A ruthenium-catalyzed oxidative coupling of vinylene carbonate with isoxazoles has been developed to achieve the direct C-H formylmethylation of a diverse array of arylisoxazoles utilizing the isoxazole ring as the directing group. A simple manipulation of the established reaction conditions leads to the formation of fused-anthranils. Importantly, the vinylene carbonate functions as both a formylmethyl cation equivalent through a decarboxylation process and an acetylene equivalent. Control experiments were conducted to elucidate a plausible mechanism. This methodology is expected to provide a facile and expeditious approach for the synthesis of formylmethyl isoxazoles and fused-anthranils.