Inorganic base-mediated stereoselective hydroamination of arylalkynes with imidazole: An efficient access to N-Vinylimidazoles

A metal-free inorganic base-mediated highly stereoselective hydroamination of arylalkynes with imidazoles has been developed, and the corresponding N-vinylimidazoles were obtained in good yields and with moderate to excellent stereoselectivities (up to 99:1). For the electron rich alkynes, the reaction system of CsOH·H2O/NMP/140 °C led to the predominant formation of E-addition products, while the reaction system of KOH/NMP/90 °C afforded the Z-isomers as the major product. The electron deficient alkynes furnished predominantly the E-addition products in both reaction systems. This study essentially provides a general and an efficient protocol for the synthesis of E-isomer of the N-vinylimidazoles.