Some Items of Interest to Process R&D Chemists and Engineers ■ COPPER-CATALYZED TRIFLUOROMETHYLATION OF BORONIC ACIDS WITH TRIFLUOROMETHYL IODIDE A mild method for the cross-coupling of arylboronic acids with CF3I via the merger of photoredox

A mild method for the cross-coupling of arylboronic acids with CF3I via the merger of photoredox (to generate CF3 radical) and Cu catalysis (to generate reactive Cu−aryl species) was developed by Professor Sanford and her co-worker of University of Michigan (J. Am. Chem. Soc. 2012, 134, 9034− 9037). Potassium carbonate was found a base of choice for the promotion of transmetalation in DMF solvent. This method demonstrates the feasibility of achieving Cu-catalyzed trifluoromethylation via a radical pathway of a wide variety of aromatic and heteroaromatic substrates bearing many common functional groups. Aromatic boronic acids bearing either electrondonating (tert-butyl, methoxy) or electron-withdrawing (cyano, trifluoromethyl, fluoro, methyl ester) substituents underwent trifluoromethylation to give the trifluoromethylated products in high yield. A variety of different potentially reactive functional groups (such as hydroxy, iodo, ketone, aldehyde, ester, and amide) was well-tolerated. Boronic acids derived from heteroaromatics such as pyridine, quinoline, furan, and thiophene could be trifluoromethylated in modest to good yields.