Facile Synthesis of Vinyl Boronate Esters via Dehydrogenative Borylation of Alkenes Enabled by a Co-MOF Catalyst: An Additive-Free Approach

Facile synthesis of vinyl boronate esters via dehydrogenative borylation of terminal alkenes was accomplished by employing a recyclable cobalt-metal-organic framework (MOF) catalyst and dimethylformamide (DMF) solvent as a hydrogen scavenger. This process avoids using special ligands, high temperatures, long reaction time, and additional hydrogen acceptors and can be carried out in air. A wide range of mono- and disubstituted aromatic alkenes, along with aliphatic alkenes, were well tolerated under mild reaction conditions. The synthetic importance of vinyl boronate esters was demonstrated by installing various functionalities into the vinylic C-B bond. Importantly, the catalyst could be reused up to 5 times without significant loss in activity. The proposed catalytic cycle of the borylation reaction has been evaluated based on stoichiometric reactions and density functional theory (DFT) calculations.