Acceleration of Suzuki-Miyaura- and Stille-type coupling reactions by irradiation with near-UV-A light.

Irradiation of a palladium catalyst bearing UV-A-absorbing phosphine ligands with low-intensity UV-A light leads to higher conversions of reactants at lower temperatures and an increased selectivity towards the cross-coupling product in Suzuki-Miyaura- and Stille-type reactions. The examples studied illustrate that a selective energy input into the catalyst by irradiation leads to more selective conversions under milder reaction conditions. With the availability of affordable and energy-efficient UV-A LED light sources, selective heating of the catalyst by light can be envisaged as a general strategy to increase the performance of a catalyst.