Construction of 1,2,3-Benzodiazaborole by Electrophilic Borylation of Azobenzene and Nucleophilic Dialkylative Cyclization
Masanori Shigeno, Masaya Imamatsu, Yusuke Kai, Moe Kiriyama, Shintaro Ishida, Kanako Nozawa‐Kumada, Yoshinori Kondo
Abstract
1,2,3-Benzodiazaboroles can be conveniently prepared from azobenzenes by a two-step protocol involving electrophilic ortho-borylation with BBr3 and dialkylative cyclization with the Grignard reagent. The methodology provides a diverse range of products equipped with functionalities from azobenzenes containing substituents (Me, t-Bu, F, Cl, Br, I, and OCF3) and a series of Grignard reagents (alkyl- and arylmagnesium reagents). Moreover, this study displays the moderate aromaticity of the B–N–N-containing five-membered ring and mechanistic investigations of the cyclization reaction.
Topics & Concepts
ChemistryBorylationElectrophileReagentNucleophileRing (chemistry)AlkylAzobenzeneMedicinal chemistryCombinatorial chemistryOrganic chemistryMoleculeArylCatalysisOrganoboron and organosilicon chemistryCatalytic Cross-Coupling ReactionsSulfur-Based Synthesis Techniques