Stereoselective Cyclization Cascade of Dihydroquinoxalinones by Visible-Light Photocatalysis: Access to the Polycyclic Quinoxalin-2(1 H )-ones.

An intriguing stereoselective visible-light photocatalysis of dihydroquinoxalinone derivatives has been realized via cyclization with or without the solvolysis cascade. The reactions provided the polycyclic ring structures with efficient formation of multiple bonds and with high stereoselectivity. X-ray crystallography unequivocally determined the structures of five polycyclic products.