Chromoselective synthesis of sulfonyl chlorides and sulfonamides with potassium poly(heptazine imide) photocatalyst

Among external stimuli used to promote a chemical reaction, photocatalysis possesses a unique one—light. Photons are traceless reagents that provide an exclusive opportunity to alter chemoselectivity of the photocatalytic reaction varying the color of incident light. This strategy may be implemented by using a sensitizer capable to activate a specific reaction pathway depending on the excitation light. Herein, we use potassium poly(heptazine imide) (K‐PHI), a type of carbon nitride, to generate selectively three different products from S‐arylthioacetates simply varying the excitation light and otherwise identical conditions. Namely, arylchlorides are produced under UV/purple, sulfonyl chlorides with blue/white, and diaryldisulfides at green to red light. A combination of the negatively charged polyanion, highly positive potential of the valence band, presence of intraband states, ability to sensitize singlet oxygen, and multi‐electron transfer is shown to enable this chromoselective conversion of thioacetates.
Photons are traceless reagents in the photocatalytic system, able to control the reaction pathway. Herein, the carbon nitride photocatalyst is used to obtain three products from the same reaction mixture only varying the excitation light. The developed method is optimized for the synthesis of sulfonyl chlorides and amides. Finally, through different physico‐chemical methods, the rationale behind the chromoselective synthesis is explained.