Visible-Light-Induced Formation of Thiavinyl 1,3-Dipoles: A Metal-Free [3+2] Oxidative Cyclization with Alkynes as Easy Access to Thiophenes
Baihui Zheng, Xiaotong Li, Yang Song, Shuyang Meng, Yifei Li, Qun Liu, Ling Pan
Abstract
A visible-light-induced [3+2] oxidative cyclization of various alkynes with easily available ketene dithioacetals as the previously unknown thiavinyl 1,3-dipoles in the presence of an acridine photosensitizer is reported. A series of multisubstituted thiophenes were achieved regioselectively in ≤98% yields under very mild metal-free conditions without other additives. This reaction could tolerate a wide range of substrates and achieve good efficiency in large-scale syntheses. The reaction mechanism and their applications are described in detail to reveal the reactivity of the new 1,3-dipoles and the selectivity of the reactions.
Topics & Concepts
ChemistryKetenePhotochemistryReactivity (psychology)SelectivityPhotosensitizerCombinatorial chemistryVisible spectrumAcridine derivativesOxidative phosphorylationAcridineMetalOrganic chemistryStereochemistryCatalysisPathologyAlternative medicineMedicineBiochemistryPhysicsOptoelectronicsSulfur-Based Synthesis TechniquesCatalytic C–H Functionalization MethodsRadical Photochemical Reactions