UV Light Induced Direct Synthesis of Phenanthrene Derivatives from a Linear 3-Aryl-N-(arylsulfonyl) Propiolamides

A novel photochemical approach for the synthesis of phenanthrene derivatives from linear 3-aryl-N-(arylsulfonyl) propiolamides via a tandem radical Smiles rearrangement/C-S bonding/Mallory reaction is disclosed. The control experiment results and isolation of the key intermediates give further insight into the reaction mechanism. Gram scale reaction using a flow reactor demonstrated the synthetic potential applications of our protocol.