Site-Selective [4+2] and [4+3] Annulations of Arylboronic Acids with Cyclic Diaryliodoniums for Polycyclic Arenes Synthesis

Abstract

A facile access to functionalized triphenylenes through tandem Suzuki-Miyaura and intramolecular C-C coupling between arylboronic acids and cyclic diaryliodonium salts is disclosed. More importantly, this protocol can expand to large-sized boronic acids involving naphthalene, anthracene, pyrene, triphenylene, dibenzo[b,d]thiophene, and carbazole units that bearing two competitive C(sp 2 )-H bonds, and all the cases show good α-selectivity. This α-selective [4+2] annulation provides a fast access to π-extended polycyclic arenes including [4]-and [5]carbohelicenes as well as their aza-/thia-hybrids. Moreover, the double annulation version on diboronic acids is presented as an efficient and fast route to (helical) nanographenes. In addition, selective Suzuki coupling and N-H activation cascade has been realized through the [4+3] annulation of (9Hcarbazol-1-yl)boronic acids and cyclic iodoniums, providing nonalternant molecules bearing N-doped pentagon-heptagon pair in good yields.