Ruthenium-catalyzed regioselective 1,3-methylene transfer by cleavage of two adjacent sigma-carbon-carbon bonds: an easy and selective synthesis of highly substituted benzenes

We report a new ruthenium-catalyzed 6-endo-dig cyclization of 6,6-cycloalkylidenyl-3,5-dien-1-ynes, which produces highly substituted benzenes with considerable structural reorganization. In this process, we observe a regioselective 1,3-methylene migration via extrusion from a cycloalkylidenyl ring, in addition to a regiocontrolled 1,2-alkyl migration. This cyclization provides an easy and convenient synthesis of complex benzenes bearing various different substituents.