The benzoin condensation is a reaction (often called a condensation reaction, for historical reasons) between two aromatic aldehydes, particularly benzaldehyde. The reaction is catalyzed by a nucleophile such as the cyanide anion or an N-heterocyclic carbene. The reaction product is an aromatic acyloin with benzoin as the parent compound. An early version of the reaction was developed in 1832 by Justus von Liebig and Friedrich Woehler during their research on bitter almond oil. The catalytic version of the reaction was developed by Nikolay Zinin in the late 1830s, and the reaction mechanism for this organic reaction was proposed in 1903 by A. J. Lapworth.