Chemoenzymatic Decarboxylative Bromination of Acetylenic Acids Using Vanadium-Dependent Chloroperoxidase

Haloalkynes are versatile building blocks in organic transformations. However, the traditional synthesis of these compounds, using either Br₂ or <i>N</i>-bromosuccinimide, suffers from significant waste generation. Herein, we use vanadium-dependent chloroperoxidase from <i>Curvularia inaequalis</i> (<i>Ci</i>VCPO) for the <i>in situ</i> generation of reactive hypobromite, which enables the chemoenzymatic decarboxylation bromination of phenylpropiolic acids. A broad range of substrates were converted into the corresponding haloalkynes in up to 99% conversion and 99% chemoselectivity. This method was also cascaded with chemocatalysis to yield various important building blocks. This work not only reports a mild and environmentally friendly alternative to prepare the versatile haloalkynes but also expands the oxidation chemistry of vanadium-dependent chloroperoxidases.