Synthesis of Phenylferrocene in Supercritical Carbon Dioxide

Abstract

The environmentally benign Suzuki cross-coupling reaction was developed by using ScCO2(Supercritical CO2) instead of traditionally organic solvent. In the paper the compound phenylferrocene was synthesized by the Suzuki cross-coupling reaction of iodoferrocene and phenylboronic acids in ScCO2/PEG (polyethylene glycol) with excellent yield ratio in the presence of ligand-free Pd/C catalyst and K2CO3.1.5H2O as base. The Pd/C catalyst can be reused by simply washing sequence and CO2can be recycled after depressurization. The catalytic reaction conditions were optimized in the reaction using ScCO2as solvent.

The Role of PEG on Pd- and Cu-Catalyzed Cross-Coupling Reactions

“…Li and co-workers observed a trace amount of the desired cross-coupled product, however, using scCO 2 /PEG-1000, with Pd/C (10 mol%), K 2 CO 3 •1.5H 2 O at 100 °C for 24 hours, gave the product in 78% yield. 38 PEG derivatives were also reported as surfactants for a ligand-free Suzuki-Miyaura cross-coupling catalyzed by Pd(OAc) 2 in water. 39 PEG-800/triphenylphosphonium bromide salts (PEG-800-quat) were prepared, and acted as a better surfactant than the corresponding PEG-800/tributyl-…”