Photocyclization of enamines to access Spiroindolines and Spirooxindoles in continuous flow

•A flow chemistry approach to the UV photocyclization of aryl-enamines to spiroindolines has been developed.•The substrate scope of the UV photocyclization of aryl-enamines to spiroindolines has been explored.•The utility of this flow methodology has been demonstrated in a shortened formal synthesis of (±)-horsfiline.•A novel UV mediated oxidative decarboxylation of an indoline-2-carboxylate is described.