The α,β-unsaturated carbonyl scaffold is a cornerstone of medicinal chemistry. At the α-carbon, well-established protocols—ranging from enolate chemistry and organocatalysis to photochemical and electrochemical radical pathways—have enabled a broad array of alkylations, fluoroalkylations, and asymmetric modifications, generally with wide substrate tolerance. Functionalization at the β-position has proven more difficult, owing to the inherently low electron density of the olefinic carbon. Nevertheless, a suite of approaches has emerged in recent years to tackle this challenge, including Heck arylation, metal-directed C-H activation, radical fluoroalkylation, and visible-light-driven photocatalysis, all of which allow for the selective installation of aryl, fluorinated, or heteroatom-containing groups.Overall, the field is shifting steadily away from reliance on metals and stoichiometric reagents, moving instead toward metal-free, photo-induced, and electrochemical platforms that operate under milder and more sustainable conditions. This Review surveys recent synthetic strategies for site-selective functionalization at both the α- and β-positions of α,β-unsaturated carbonyls, and briefly discusses the mechanistic underpinnings of representative transformations.

Key words: α,β-unsaturated carbonyl, α-functionalization, β-functionalization