Synthesis of 3-Chloro-benzo[b]selenophenes from Diphenylpropynones via PhICl2/KSeCN-Mediated Successive Bond Formation

The reaction of diphenylpropynones with PhICl₂/KSeCN in DMSO was found to deliver 3-chloro-benzo[b]selenophenes via an exclusive intramolecular cyclization encompassing oxidative C-Se/C-Cl bond formation. The electrophilic Cl-SeCN, generated in situ from the reaction of PhICl₂ and KSeCN, was postulated to be crucial for annulation to occur.