40888-89-9Relevant articles and documents
Open-Shell Fluorination of Alkyl Bromides: Unexpected Selectivity in a Silyl Radical-Mediated Chain Process
Lovett, Gabrielle H.,Chen, Shuming,Xue, Xiao-Song,Houk,MacMillan, David W. C.
, p. 20031 - 20036 (2019/12/27)
We disclose a novel radical strategy for the fluorination of alkyl bromides via the merger of silyl radical-mediated halogen-atom abstraction and benzophenone photosensitization. Selectivity for halogen-atom abstraction from alkyl bromides is observed in the presence of an electrophilic fluorinating reagent containing a weak N-F bond despite the predicted favorability for Si-F bond formation. To probe this surprising selectivity, preliminary mechanistic and computational studies were conducted, revealing that a radical chain mechanism is operative in which kinetic selectivity for Si-Br abstraction dominates due to a combination of polar effects and halogen-atom polarizability in the transition state. This transition-metal-free fluorination protocol tolerates a broad range of functional groups, including alcohols, ketones, and aldehydes, which demonstrates the complementary nature of this strategy to existing fluorination technologies. This system has been extended to the generation of gem-difluorinated motifs which are commonly found in medicinal agents and agrochemicals.
Targeted fluorination with the fluoride ion by manganese-catalyzed decarboxylation
Huang, Xiongyi,Liu, Wei,Hooker, Jacob M.,Groves, John T.
supporting information, p. 5241 - 5245 (2015/04/27)
We describe the first catalytic decarboxylative fluorination reaction based on the nucleophilic fluoride ion. The reported method allows the facile replacement of various aliphatic carboxylic acid groups with fluorine. Moreover, the potential of this method for PET imaging has been demonstrated by the successful 18F labeling of a variety of carboxylic acids with radiochemical conversions up to 50-%, representing a targeted decarboxylative 18F labeling method with no-carrier-added [18F]fluoride. Mechanistic probes suggest that the reaction proceeds through the interaction of the manganese catalyst with iodine(III) carboxylates formed in situ from iodosylbenzene and the carboxylic acid substrates. Nucleophile first: An efficient manganese porphyrin catalyzed decarboxylative fluorination reaction based on a nucleophilic fluorine source is described. The potential of the described method for use in PET imaging has been demonstrated by the successful 18F labeling of various aliphatic carboxylic acids, representing the first decarboxylative 18F labeling method with no-carrier-added [18F]fluoride.
Rearrangement and double fluorination in the deiodinative fluorination of neopentyl iodide with xenon difluoride
Patrick, Timothy B.,Zhang, Likang,Li, Quinhua
, p. 11 - 15 (2007/10/03)
Alkyl iodides give products from the neopentyl rearrangement on reaction with xenon difluoride. Neopentyl iodide performs a double rearrangement and yields a gem-difluoro product, 2,2-difluoro-3-methylbutane. Studies of the mechanism show that an alkene intermediate is involved in the double rearrangement process. Alkenes can be substituted as substrates in reaction with xenon difluoride-iodine to give gem-difluoro products. 13C Labeling verifies the skeletal rearrangement process.
