Suzuki‐Miyaura Cross‐Coupling Reaction Using Palladium Catalysts Supported on Phosphine Periodic Mesoporous Organosilica

Abstract

Phosphine periodic mesoporous organosilicas (R‐P‐PMO‐TMS: R=Ph, tBu), which possess electron‐donating alkyl substituents on the phosphorus atom, were synthesized using bifunctional compounds with alkoxysilyl‐ and phosphino groups, bis[3‐(triethoxysilyl)propyl]phenylphosphine borane (1 a) and bis[3‐(triethoxysilyl)propyl]‐tert‐butylphosphine borane (1 b). Immobilization of Pd(0) species was performed to give R‐P‐Pd‐PMO‐TMS: R=Ph (2 a), tBu (3 a), respectively. The Pd(0) immobilized 2 a and 3 a were applicable as catalysts for Suzuki‐Miyaura cross‐coupling reactions of aryl chlorides with phenylboronic acid. It was revealed that 3 a bearing more electron‐donating tBu groups exhibited higher catalytic activity. Various functional groups including both electron withdrawing and donating substituents were compatible in the system. The recyclability of 3 a was examined to support its moderate utility for the recycle use.

Latest Developments on Palladium- and Nickel-Catalyzed Cross-Couplings Using Aryl Chlorides: Suzuki–Miyaura and Buchwald–Hartwig Reactions

“…Nakajima et al reported the SM coupling using a Pd catalyst supported on phosphine periodic mesoporous organosilica L6. 52 They used Pd(dba)2 (2.5 mol% Pd) as a transition metal source. Under these conditions, the SM reaction using 4-chlorophenol and 4-(mercapto)chlorobenzene as substrates did not proceed.…”