The hydrogen-bond as a configurational lock in the photocyclisation of dibenzoylmethane o-halogenoanils: wavelength dependence of this reaction
Abstract
The tautomers (1, XCl, Br, or I) of anils photocyclise to the phenanthridine derivative (2) with varying efficiencies depending on the halogen and the solvent; owing to the low energies of the first excited states the quantum yields vary with irradiation wavelength.