Rapid access to polycyclic thiopyrylium compounds from unfunctionalized aromatics by thia-APEX reaction

We developed a sulfur-embedding annulative pi-extension (thia-APEX) reaction that could construct a sulfur-embedding cationic hexagonal aromatic ring, thiopyrylium, onto unfunctionalized aromatics in one step. The key of thia-APEX is the use of S-imidated ortho-arenoyl arenethiols, and a variety of pi-extended thiopyryliums can easily be synthesized. The synthesized thiopyryliums showed diverse absorption and emission properties over the visible light to NIR region, depending on minor structural differences.

Automated summary

We have developed a sulfur-embedding annulative pi-extension (thia-APEX) reaction to efficiently construct a sulfur-embedding cationic hexagonal aromatic ring called thiopyrylium onto unfunctionalized aromatics in a one-step process. The key of the thia-APEX reaction lies in the utilization of S-imidated ortho-arenoyl arenethiols, enabling easy synthesis of diverse pi-extended thiopyryliums. The synthesized thiopyryliums exhibit various absorption and emission properties across the visible light to NIR region, depending on minor structural variations.