Tandem catalytic efficient olefin epoxidation with integrated production of nicotinamide derivatives

Summary

Heterogeneous catalytic olefin epoxidation is an important reaction for industrial production of both bulk and fine chemicals. We report here a tandem catalytic efficient olefin epoxidation with integrated production of nicotinamide derivatives in which 3-cyanopyridine was shown to be highly effective and promoted the selective formation of epoxides by using MgAl hydrotalcites as the catalyst. Selectivity of 98% and conversion of 93% were achieved within 3 h at 50°C; meanwhile, 3-cyanopyridine was simultaneously converted into high value-added nicotinamide derivatives with 87% conversion at 4 equiv styrene for each reaction cycle. Designed experiments revealed that the introduction of 3-cyanopyridine-forming dehydrogenated peroxyhydroxamic acid, a key reactive oxygen species for epoxidation, activated the carbon=carbon double bond and promoted the formation of epoxidation product. The generality of the tandem catalytic approach containing base and radical catalysis for this reaction was demonstrated by selective epoxidation of other olefins with similar performance.