Rh(iii)-Catalysed cascade C–H imidization/cyclization of N-methoxybenzamides with isoxazolones for the assembly of dihydroquinazolin-4(1H)-one derivatives

Abstract

Using isoxazolones as viable imidizating reagents, an efficient Rh(III)-catalysed C–H imidization/cyclization cascade has been developed for the specific assembly of dihydroquinazolin-4(1H)-ones with the equipment of a quaternary carbon center. This protocol features the simultaneous formation of two novel C–N bonds in a one-pot fashion with good compatibility and practicality. Combined DFT calculations and experimental studies clarified the tandem C–H activation/oxidation addition/C–H amination/isomerization/intramolecular cyclization sequence for this transformation, in which the Rh(V) nitrenoid and the imine species might be involved as active intermediates.