Effect of carboxyl-functionalized imidazolium salts on the rhodium-catalyzed hydrosilylation of alkene

A series of carboxyl-functionalized imidazolium salts were synthesized. Hydrosilylation reaction of carboxyl-functionalized imidazolium salts (1b–4b, 1c–3c) exhibited higher levels of styrene conversion and higher levels of β-adduct selectivity. In particular, no ethylbenzene as hydrogenation product could be yielded at all when Rh(PPh3)3Cl/carboxyl-functionalized imidazolium inner salts (1c–3c), respectively, were used as the catalyst. The Rh(PPh3)3Cl/carboxyl-functionalized imidazolium salts catalyst system can be reused without noticeable loss of catalytic activity.