<i>N</i>-Methylphenothiazine <i>S</i>-Oxide Enabled Oxidative C(sp<sup>2</sup>)–C(sp<sup>2</sup>) Coupling of Boronic Acids with Organolithiums via Phenothiaziniums
Tatsuki Yoshida, Yuki Honda, Tatsuya Morofuji, Naokazu Kano
Abstract
Herein, we report the development of a transition-metal-free oxidative C(sp2)–C(sp2) coupling of readily available boronic acids and organolithiums via phenothiazinium ions. Various biaryl, styrene, and diene derivatives were obtained using this reaction system. The key to this process is N-methylphenothiazine S-oxide (PTZSO), which allows efficient conversion of boronic acids to phenothiazinium ions. The mechanism of phenothiazinium formation using PTZSO was investigated using theoretical calculations and experiments, which provided insight into the unique reactivity of PTZSO.
Topics & Concepts
ChemistryBoronic acidStyreneReactivity (psychology)IonOxideOxidative coupling of methaneCombinatorial chemistryOxidative phosphorylationMedicinal chemistryOrganic chemistryCatalysisBiochemistryAlternative medicinePathologyCopolymerMedicinePolymerCatalytic Cross-Coupling ReactionsCatalytic C–H Functionalization MethodsCoordination Chemistry and Organometallics