Catalyst-free chemoselective reduction of the carbon–carbon double bond in conjugated alkenes with Hantzsch esters in water

A simple, efficient and green protocol for chemoselective reduction of carbon–carbon double bond in conjugated alkenes with Hantzsch esters is described. Without any additional catalysts, a series of conjugated alkenes with strong electron-withdrawing groups were reduced in water with excellent yield. Functional groups such as nitrile, ester, nitro, fluoro, chloro, bromo, furanyl and benzyl are all tolerated by the reaction conditions employed.