Regiodivergent Functionalization of Isoquinoline-1,3(2H,4H)-dione Derivatives via Aerobic Umpolung

A mild and green methodology for the regiodivergent functionalization of isoquinoline-1,3(2H,4H)-diones under aerobic conditions was developed. Under a catalytic amount of base, heteroatom nucleophiles went through an imide opening/ring contraction sequence to give the thermodynamic controlled product; while carbon based nucleophiles led to kinetic controlled aldol type product. Moreover, the aldol type product was transformed into the benzo[c]phenanthridine core structures under transition metal free condition, which provides an environmental benign access to this framework.