Visible Light-Induced Direct S<sub>0</sub> → T<sub><i>n</i></sub> Transition of Benzophenone Promotes C(sp<sup>3</sup>)–H Alkynylation of Ethers and Amides
Koki Matsumoto, Masaya Nakajima, Tetsuhiro Nemoto
Abstract
Benzophenone has an S0 → S1 absorption band at 365 nm. However, the rarely reported S0 → Tn transition occurs upon irradiation at longer wavelengths. Herein, we employed benzophenone as a catalyst and exploited its S0 → Tn transition in C(sp3)–H alkynylations with hypervalent iodine reagents. The selective benzophenone excitation prevented alkynylating reagent decomposition, enabling the reaction to proceed under mild conditions. The reaction mechanism was investigated by spectroscopic and computational studies.
Topics & Concepts
ChemistryBenzophenoneAlkynylationVisible spectrumPhotochemistryStereochemistryOrganic chemistryOptoelectronicsCatalysisPhysicsRadical Photochemical ReactionsCatalytic C–H Functionalization MethodsSulfur-Based Synthesis Techniques