Regiodivergent C-N Coupling of Quinazolinones Controlled by the Dipole Moments of Tautomers.

Herein, we report that the dipole moments of tautomers can be the controlling factor for regiodivergent synthesis of either 14 H -quinazolino[3,2- f ]phenanthridin-14-ones or 6 H -quinazolino[1,2- f ]phenanthridin-6-ones, selectively, from unmasked 2-([1,1'-biphenyl]-2-yl)quinazolin-4(3 H )-one. An intramolecular C(sp 2 )-NH coupling reaction mediated by PhI(OCOOCF 3 ) 2 could lead to two different regioisomers selectively at different temperatures when the dielectric constants of solvents like hexafluoroisopropanol and trifluoroacetic acid matched with the tautomer's dipole moments.