[Ph3C][B(C6F5)4]-catalyzed aza-Michael-type reaction of vinylpyridines with primary/secondary amines

Abstract

Aza-Michael-type reaction of vinylpyridines with amines catalyzed by easily available and non-metal catalyst [Ph3C][B(C6F5)4] has been developed. This protocol is applicable to a broad range of aliphatic and aromatic primary/secondary amines, which generally gave 100% anti-Markovnikov products in 25-99% yields. This is a simple and highly atom-economic method to prepare amine derivatives bearing pyridyl moieties. Under identical conditions, styrenes and vinylpyridines showed different reactivity with amines (hydroarylation vs. aza-Michael addition), which is believed to be determined by the electronic nature of alkene substrates.