The regio- and stereo-chemistries of the (2π+2π) photocycloaddition of electron-deficient ethenes to isoquinolin-1(2H)-one

The (2 pi + 2 pi) photocycloaddition of isoquinolin-1(2H)-one to electron-deficient ethenes is efficient, regiospecific and highly stereoselective: 254 nm irradiation of the acrylonitirile adduct induces retroadditon and rearrangement to an N-vinylisoindolinone with equal efficiencies.