Highly Selective Reduction of α, β-Unsaturated Aldehydes and Ketones under Ambient Conditions using Tetraalkylphosphonium-based Ionic Liquids

Abstract

An efficient and green protocol for highly selective reduction of α,β-unsaturated aldehydes and ketones at room temperature is described in a range of ionic liquids, in the absence of noble metal catalysts, by using NaBH4 as reducing agent. Most notably, using [P6,6,6,14][N(CN)2] ionic liquid, in absence of organic solvent, within 10 min, 97% conversion of cinnamaldehyde was achieved with 100% selectivity towards cinnamyl alcohol. The ionic liquid was easily recycled without any noticeable decline in activity. The reduction protocol was further extended to a variety of α,β-unsaturated aldehydes and ketones.