Recent Advances in the Synthesis of Citronellal from Citral

Abstract (±)-Citronellal is mainly derived from mint plants and is widely recognized as a key ingredient in many functional products, including (−)-menthol, (±)-isoamyl alcohol, and (±)-citronellol. Asymmetric hydrogenation of citral is the most effective synthetic method to obtain citronellal with high enantioselectivity. This Review provides an overview of the recent advancements in the synthesis of citronellal from citral, with a focus on industrial production processes and key advances in relevant academic literature.