Microreactor Suzuki-Miyaura reaction

The capillary microreactor with an incorporated Pd catalyst has been tested in the Suzuki-Miyaura reaction for 4 days at 80 °C at a flow rate of 0.05 pl/min. A 15-20% palladium leaching was observed after 4 days, although this seemed to occur at the early stages of the reaction. This approach was extended to fused silica capillaries with an internal diameter of 100 pm and glass microchips with a channel dimension of 150 pm [51]. Nearly complete conversion was also observed in Sonogashira coupling of p-iodoacetophenone with phenylacetylene, with no byproduct formation [52]. 

In most cases microwave reactions have been conducted in a batch system, but very recently the use of a microflow system for microwave reactions has been reported. For example, Suzuki-Miyaura coupling of aryl halides with phenylboronic acid to form biaryls is promoted by microwave irradiation of the supported Pd catalyst (Table 5.1). A thin, gold film patch located on the outside surface of the base of a glass microreactor is quite effective for absorbing microwaves. 

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