Piperidine Promoted Regioselective Synthesis of α, β-unsaturated Aldehydes

An efficient, facile and regioselective synthesis of α,β-unsaturated aldehydes from β-hydroxynitriles is reported. The reaction is carried out using DIBAL-H and promoted by piperidine under dry conditions at a temperature of -78 oC and can be described as a concomitant reduction-elimination reaction. The same reaction if carried out in the absence of piperidine gives mainly the uneliminated reduction product. The products formed are of immense importance as synthons in a large number of chemical reactions and biological processes.