Recent Developments in Defluorinative Functionalization of β‐Trifluoromethyl Enones

The functionalization of perfluoroalkylated or fluorinated compounds via selective CF bond activation represents an emerging method for the synthesis of structurally diverse and complex molecules. However, due to the inherent low reactivity of CF bonds in terms of kinetic and thermodynamic stabilities, coupled with the steric hindrance caused by the shielding effect of the three fluorine atoms, methods that transform C(sp 3 )F bonds within the trifluoromethyl group are challenging but highly desirable. β ‐ Trifluoromethyl enones (β‐CF 3 ‐enones), a class of versatile building blocks, include three reactive sites within their structure: an electrophilic carbonyl moiety, an α,β‐unsaturated alkenyl system, and a β‐attached CF 3 group. Over the past decades, the defluorinative transformation of β‐trifluoromethyl enones, involving one to three CF bond cleavages, coupled with the simultaneous functionalization of the α,β‐unsaturated alkenyl system and/or the carbonyl group, unlocks their new versatility in synthetic chemistry. In this review, we categorize these recent developments into four classes, including (1) hydrodefluorination of β‐trifluoromethyl enones under reductive conditions, (2) hydrodefluorophosphorylation and hydrodefluoroamination of β‐trifluoromethyl enones in the presence of a reductant and P ‐/ N ‐nucleophiles, (3) defluorophosphination and/or defluorophosphorylation of β‐trifluoromethyl enones with P ‐nucleophiles, and (4) defluorinative cyclization of β‐trifluoromethyl enones for the construction of diverse heterocycles. Specific emphasis is placed on the discussion of the reaction design, reaction mechanisms, and the substrate scopes. Further perspective on the future development of this growing area is also provided.