Regioselective synthesis of oxopyrrolidine analogs via iodine-catalysed Markovnikov addition reaction: Friedel-crafts alkylation reactions, preparation of tryptophan dioxygenase inhibitors, pyridyl-ethenyl-indoles as potential anticancer immunomodulators, preparation of plant-growth inhibitors, michael addition reactions, synthesis of cyclooxygenase-1 (COX-1)/cyclooxygenase-2 (COX-2) inhibitors.