Continuous-flow photo-induced decarboxylated annulative access to fused Imidazole derivatives via Ruthenium immobilized microreactor

Visible-light driven continuous-flow decarboxylative annulation has been achieved to construct valuable fused imidazole derivatives with high yields via ruthenium catalyst immobilized microreactor under open atmosphere. The sailent features of this chemistry include the use of L-proline and α-azidochalcone as precursors of α-amino radical and 2H-azirine via photo-induced decarboxylation and denitrogenation respectively, to give the annulated imidazole derivatives by formation of two new C-N bonds. Moreover the novel, environmentally benign and efficient continuous-flow protocol is further promoted by carrying out in a Ru+3 immobilized polydimethylsiloxane (PDMS) microreactor under fluorescent or white LED light, enabling excellent yields (70-94%) at significantly shorter time (2 min) over the long reaction (16 h) of batch protocol.