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

Abstract

A silica-supported precatalyst, Pd-PEPPSI-IPent-SiO₂ , 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 Csp³ -Csp² coupling of secondary alkylzinc reagents to (hetero)aromatics has been achieved with high selectivity with Pd-PEPPSI-IPent-SiO₂ . These couplings required residence times as short as 3 minutes to effect completion of these challenging transformations with excellent selectivity for the nonrearranged product.