Recyclable and Reusable [RuCl2(p-cymene)]2/Cu(OAc)2/PEG-400/H2O System for Oxidative C-H Bond Alkenylations: Green Synthesis of Phthalides.

Abstract

[RuCl2(p-cymene)]2 in a mixture of poly(ethylene glycol) (PEG-400) and water is shown to be an extremely efficient catalyst for the cross-dehydrogenative C-H bond alkenylation reaction between benzoic acids and alkenes. The reaction could be conducted at 80 °C using Cu(OAc)2·H2O as oxidant, yielding a variety of phthalide derivatives in good to excellent yields. More importantly, both [RuCl2(p-cymene)]2 and Cu(OAc)2 in the PEG-400/H2O system could be easily recycled and reused six times without any loss of catalytic activity.