Enantioselective palladium-catalyzed addition of malonates to 3,3-difluoropropenes

Palladium-catalyzed alkynylation of allylic gem-difluorides

Herein, a palladium-catalyzed regioselective alkynylation, esterification, and amination of allylic gem-difluorides via C-F bond activation/transmetallation/β-C elimination or nucleophilic attack has been achieved. This innovative protocol showcases an extensive substrate range and operates efficiently under mild reaction conditions, resulting in high product yields and Z-selectivity. Particularly noteworthy is its exceptional tolerance towards a wide array of functional groups. This developed methodology provides effective and convenient routes to access a diverse array of essential fluorinated enynes, esters and amines.

Palladium-Catalyzed Diversified Synthesis of Monofluorinated Alkenes from Allylic gem-Difluorides through Pd-OH Intermediate

Significant advancements in synthesis of monofluoroalkenes via palladium-catalyzed reactions involving allylic gem-difluorides and diverse nucleophiles have been achieved. This method allows regioselective arylation, alkylation, allylation, alkenylation, and hydrogenation of allylic gem-difluorides, yielding high Z-selectivity and favorable product yields under mild conditions. Tolerating various functional groups, these transformations utilize a common Pd-OH intermediate. Additionally, employing triple Pd-catalyzed cross-coupling yields diverse trisubstituted alkenes efficiently.

Stereospecific Nickel-Catalyzed Cross-Electrophile Coupling Reaction of Alkyl Mesylates and Allylic Difluorides to Access Enantioenriched Vinyl Fluoride-Substituted Cyclopropanes

Cross-electrophile coupling reactions involving direct C-O bond activation of unactivated alkyl sulfonates or C-F bond activation of allylic gem-difluorides remain challenging. Herein, we report a nickel-catalyzed cross-electrophile coupling reaction between alkyl mesylates and allylic gem-difluorides to synthesize enantioenriched vinyl fluoride-substituted cyclopropane products. These complex products are interesting building blocks with applications in medicinal chemistry. Density functional theory (DFT) calculations demonstrate that there are two competing pathways for this reaction, both of which initiate by coordination of the electron-deficient olefin to the low-valent nickel catalyst. Subsequently, the reaction can proceed by oxidative addition of the C-F bond of the allylic gem-difluoride moiety or by directed polar oxidative addition of the alkyl mesylate C-O bond.

Nickel-Catalyzed Reductive Allyl-Aryl Cross-Electrophile Coupling via Allylic C-F Bond Activation

Nickel-catalyzed reductive cross-coupling of allylic difluorides with aryl iodides was achieved via allylic C-F bond activation. Based on this protocol, a series of γ-arylated monofluoroalkenes were synthesized in moderate to high yields with high Z-selectivities. Mechanistic studies suggest that the C-I bonds of the aryl iodides and the C-F bonds of the allylic difluorides were cleaved via oxidative addition and β-fluorine elimination, respectively, where the oxidative addition of less reactive C-F bonds was avoided to permit their transformation.

Photocatalytic Cyclization/Defluorination Domino Sequence to Access 3-Fluoro-1,5-dihydro-2H-pyrrol-2-one Scaffold

We herein report an unprecedented photoinduced cyclization/defluorination domino process of N-allylbromodifluoroacetamide with cyclic secondary amines. Consequently, a wide array of valuable 3-fluoro-1,5-dihydro-2H-pyrrol-2-ones were facilely prepared from readily available starting materials under mild conditions. Preliminary mechanistic investigations suggest that a radical chain propagation and amine-promoted defluorination pathway are presumably involved in this transformation.

Catalytic asymmetric synthesis of monofluoroalkenes and gem-difluoroalkenes: advances and perspectives

The latest achievements in the catalytic asymmetric synthesis of both monofluoro- and gem-difluoroalkenes are discussed.