Scheme 5. Potential catalytic cycles for selected side-products, based on the reaction dataset correlations. We expect all steps resulting in loss of HBr to involve base. Optimization using automated flow technology. We recognized that continuous flow platforms could be used in the study of our complex reaction chemistry. We were particularly interested in whether optimization to one side product could be achieved, which batch optimization might struggle with. Our fully automated continuous flow setup allows the rapid exploration of reaction space through computer-controlled pumps, reactors and on-line HPLC. Given the insolubility of K2CO3 in organic solvents, we chose to employ a heated packed bed reactor containing K2CO3. We investigated the effect of reaction parameters using DMF as the reaction solvent. Employing 'Design of Experiments' (DoE) methodology (see supporting information for full details) we assessed the effect of temperature (130-200 °C), residence time (13.5-27 mins) and catalyst loading (5-15 mol%). Notably, we observed that the selectivity of the reaction 1a→2a could be altered to favor the formation of biaryl 4a at high temperature and catalyst loading in DMF (Figure ). Indeed, with 15 mol% of Pd(OAc)2 and dppe at 200 °C, with a residence time of 26 minutes, 4a is formed in 70% yield. The result highlights the complementarity of the flow screening approach. For lower catalyst loadings (5 and 10 mol%), the highest conversion to 4a is seen at high temperature and residence time. On the other hand, for both catalyst loadings, poorer conversion to 4a was seen at both high temperature, short residence time and low temperature, high residence times. The results highlight the potential of the continuous flow platform optimization technology.