A reaction @[email protected] in which the bond arrangement around an initially double-bonded carbon atom (typically a carbonyl carbon atom) has been transformed from trigonal to tetrahedral. For example, aldol in the @[email protected] of acetaldehyde (but most tetrahedral intermediates have a more fleeting existence).
PAC, 1994, 66, 1077. (Glossary of terms used in physical organic chemistry (IUPAC Recommendations 1994)) on page 1173 [Terms] [Paper]