An efficient Cu-catalyzed cascade reaction involving N–O bond cleavage and C–C/C–N/N–N bond formations is developed to afford various 1,3- and 1,3,4-substituted pyrazoles.
A flow system to perform Chan–Lam coupling reactions of various amines and arylboronic acids has been realised employing molecular oxygen as an oxidant for the re-oxidation of the copper catalyst enabling a catalytic process. A tube-in-tube gas reactor has been used to simplify the delivery of the oxygen accelerating the optimisation phase and allowing easy access to elevated pressures. A small exemplification library of heteroaromatic products has been prepared and the process has been shown to be robust over extended reaction times.