The vinylfluoro group as an acetonyl cation equivalent: stereoselective synthesis of 6-substituted 4-hydroxy pipecolic acid derivatives

Formation of Fluorovinyl Spiro-[imidazole-indene] and α-Amino-β-naphthalenones via Rh(III)-Catalyzed Cascade C-H Functionalization

An efficacious method for building fluorovinyl spiro-[imidazole-indene] and α-amino-β-naphthalenone skeletons synchronously has been shown to consist of Rh(III)-catalyzed C-H functionalization between 2H-imidazoles and difluoromethylene alkynes. This protocol demonstrates a practical and straightforward route for installing fluorine elements in the envisioned position of heterocyclic compounds.

Synthesis of Ketones and Esters from Heteroatom-Functionalized Alkenes by Cobalt-Mediated Hydrogen Atom Transfer

Cobalt bis(acetylacetonate) is shown to mediate hydrogen atom transfer to a broad range of functionalized alkenes; in situ oxidation of the resulting alkylradical intermediates, followed by hydrolysis, provides expedient access to ketones and esters. By modification of the alcohol solvent, different alkyl ester products may be obtained. The method is compatible with a number of functional groups including alkenyl halides, sulfides, triflates, and phosphonates and provides a mild and practical alternative to the Tamao-Fleming oxidation of vinylsilanes and the Arndt-Eistert homologation.

Study of Uridine 5'-Diphosphate (UDP)-Galactopyranose Mutase Using UDP-5-Fluorogalactopyranose as a Probe: Incubation Results and Mechanistic Implications

Uridine 5'-diphosphate-5-fluorogalactopyranose (UDP-5F-Galp, 7) was synthesized, and its effect on UDP-Galp mutase (UGM) was investigated. UGM facilitated the hydrolysis of 7 to yield UDP and 5-oxogalactose (24), but no 11 was detected. (19)F NMR and trapping experiments demonstrated that the reaction involves the initial formation of a substrate-cofactor adduct followed by decomposition of the resulting C5 gem-fluorohydrin to generate a 5-oxo intermediate (10). The results support the current mechanistic proposal for UGM and suggest new directions for designing mechanism-based inhibitors.