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gem‐Difluoroalkenes are unique structural motifs with important applications ranging from drugs to materials. Herein, we report a novel radical‐mediated defluorinative allylation of sulfamate esters with through distal C(sp3)−H functionalization under photoredox conditions. The reaction could readily incorporate various gem‐difluoroalkene motifs into previously unfunctionalized sp3 carbon centers. The transformation allows directly dual activation of N−H and C(sp3)−H bonds via a photocatalytic and redox‐neutral process, as well as using water as environmentally friendly co‐solvent. The reaction could provide a general and operationally simple method to access gem‐difluoroalkene compounds with high diversity. [ABSTRACT FROM AUTHOR]

The direct functionalization of an aliphatic C-H bond within a complex molecule through a free-radical pathway is a valuable tool in synthetic chemistry. Herein, we developed an efficient transition-metal-free approach to generate Δ2-isoxazolines from oximes by radical-mediated C(sp3)-H oxidation. Investigation of the mechanism suggested that in the presence of Selectfluor and Bu4NI, the homolysis of the in situ formed O-I bond generated an iminoxyl radical that facilitated subsequent 1,5-H transfer and C(sp3)-H oxidation. [ABSTRACT FROM AUTHOR]

A palladium-catalyzedefficient synthesis of 5-methylisoxazolesvia oxime-mediated functionalization of unactivated olefins is described.The reaction affords a variety of 5-methylisoxazoles in moderate togood yields. To further demonstrate the utility of the method, therapid synthesis of valdecoxib and oxacillin is reported. [ABSTRACT FROM AUTHOR]

Cobalt-catalyzed enantioconvergent cross-coupling of C(sp 3 )-H bonds with in situ -generated sulfenate anions is achieved to access chiral sulfoxides, which are found in the structures of many biologically active agents. The more challenging aliphatic C-H bonds as well as sterically hindered substrates containing tertiary C-H bonds could also be tolerated well. Mechanistic studies indicate that the transformation could undergo a Co II S(O)R-mediated single-electron transfer with N -fluorocarboxamides, followed by a 1,5-hydrogen atom transfer and then a pivotal organocobalt(IV)-controlled enantioselective cross-coupling process. This novel asymmetric radical reaction for C-S bond construction could open a new door for the synthesis of sulfur-centered chiral compounds.