Metal-Free Synthesis of 9-Sulfenylphenanthrenes via HNO3/HCl-Promoted Annulation of 2-Alkynylbiaryls with Disulfides

Abstract A metal-free thiolative annulation of 2-alkynylbiaryls with disulfides has been developed. This mild and efficient approach was promoted by inexpensive HNO3/HCl and afforded a range of corresponding 9-sulfenylphenanthrenes in good to excellent yields with a broad substrate scope and high functional group tolerance. Both sulfide groups of the disulfide reagent were used in the reaction.