Search

Carbon‐fluorine bonds are stable and have demonstrated sluggishness against various chemical manipulations. However, selective transformations of C−F bonds can be achieved by developing appropriate conditions as useful synthetic methods in organic chemistry. This review focuses on C−C bond formation at monofluorinated sp3‐hybridized carbons via C−F bond cleavage, including cross‐coupling and multi‐component coupling reactions. The C−F bond cleavage mechanisms on the sp3‐hybridized carbon centers can be primarily categorized into three types: Lewis acids promoted F atom elimination to generate carbocation intermediates; nucleophilic substitution with metal or carbon nucleophiles supported by the activation of C−F bonds by coordination of Lewis acids; and the cleavage of C−F bonds via a single electron transfer. The characteristic features of alkyl fluorides, in comparison with other (pseudo)halides as promising electrophilic coupling counterparts, are also discussed. [ABSTRACT FROM AUTHOR]

Cover Picture: Cross- and Multi-Coupling Reactions Using Monofluoroalkanes (Chem. Rec. 9/2023) Alkyl fluoride, C-F bond cleavage, cross-coupling reaction, multi-component coupling reaction, Friedel-Crafts reaction Keywords: alkyl fluoride; C-F bond cleavage; cross-coupling reaction; multi-component coupling reaction; Friedel-Crafts reaction EN alkyl fluoride C-F bond cleavage cross-coupling reaction multi-component coupling reaction Friedel-Crafts reaction 1 1 1 09/12/23 20230901 NES 230901 The cover picture shows concept of utilizing monofluoroalkanes for C-C bond formations by C-F bond cleavage, where the fluorine leaving group (blue hermit crab) exuberantly shifts toward a cationic reagent/catalyst (empty shell), and the remaining alkyl group (red shell) forms new C-C bond with an incoming nucleophilic coupling counterpart (red hermit crab). [Extracted from the article]

A Ni-catalyzed oxidative C–H/C–H cross-dehydrogenative coupling (CDC) reaction was developed for constructing various highly functionalized alkyl (aryl)-substituted thiophenes. This method employs thiophenes and aliphatic (aromatic) amides that contain an 8-aminoquinoline as a removable directing group in the presence of a silver oxidant. The approach enables the facile one-step synthesis of substituted thiophenes with high functional group compatibility via double C–H bond cleavage without affecting C–Br and C–I bonds. DFT calculations verify the importance of KH2PO4 as an additive for promoting C–H bond cleavage and support the involvement of a Ni(iii) species in the reaction. [ABSTRACT FROM AUTHOR]

Copper complexes generated in situ from CuCl2, alkyl Grignard reagents, and 1,3-dienes play important roles as catalytic active species for the 1,2-hydroalkylation of 1,3-dienes by alkyl fluorides through CF bond cleavage. The alkyl group is introduced to an internal carbon atom of the 1,3-diene regioselectively, thus giving rise to the branched terminal alkene product. [ABSTRACT FROM AUTHOR]

A Ni-catalyzed oxidative C–H/C–H cross-dehydrogenative coupling (CDC) reaction was developed for constructing various highly functionalized alkyl (aryl)-substituted thiophenes. This method employs thiophenes and aliphatic (aromatic) amides that contain an 8-aminoquinoline as a removable directing group in the presence of a silver oxidant. The approach enables the facile one-step synthesis of substituted thiophenes with high functional group compatibility via double C–H bond cleavage without affecting C–Br and C–I bonds. DFT calculations verify the importance of KH2PO4 as an additive for promoting C–H bond cleavage and support the involvement of a Ni(iii) species in the reaction. [ABSTRACT FROM AUTHOR]

The reaction of arenes and heteroarenes with thio- and selenophene derivatives proceeds via double C-H bond cleavage by using Cu(O-Ac)2 or Cu(O-Ac)2/AgSbF6 as an oxidant. [ABSTRACT FROM AUTHOR]