Pd‐PEPPSI‐IPent‐SiO₂: A Supported Catalyst for Challenging Negishi Coupling Reactions in Flow

A silica‐supported precatalyst, Pd‐PEPPSI‐IPent‐SiO 2 , has been prepared and evaluated for its proficiency in the Negishi cross‐coupling of hindered and electronically deactivated coupling partners. The precatalyst Pd‐PEPPSI‐IPent loaded onto packed bed columns shows high catalytic activity for the room‐temperature coupling of deactivated/hindered biaryl partners. Also for the first time, the flowed Csp 3 –Csp 2 coupling of secondary alkylzinc reagents to (hetero)aromatics has been achieved with high selectivity with Pd‐PEPPSI‐IPent‐SiO 2 . These couplings required residence times as short as 3 minutes to effect completion of these challenging transformations with excellent selectivity for the nonrearranged product.