Copper-catalyzed decarboxylative hydroboration of phenylpropiolic acids under ligand-free or both ligand- and base-free conditions

An efficient copper-catalyzed decarboxylative hydroboration of phenylpropiolic acids with bis(pinacolato)diboron was developed, affording β-vinylboronates as the only products in high yields. Extra hydrogen sources such as methanol are not needed in this catalytic system. This reaction could be performed successfully under ligand- and base-free conditions. It demonstrated that phenylpropiolic acids can be employed as alkyne synthons in the hydroboration reaction and exhibited good reactivity and higher selectivity than terminal alkynes.

Copper-catalyzed decarboxylative hydroboration of phenylpropiolic acids with bis(pinacolato)diboron proceeds under ligand-free or both ligand- and base-free conditions, affording β-vinylboronates in high yields.Figure optionsDownload as PowerPoint slide