Electrochemical Fluorination of Vinyl Boronates through Donor‐Stabilized Vinyl Carbocation Intermediates. (3rd February 2022)

• Record Type: Journal Article
• Authors: Wigman, Benjamin; Lee, Woojin; Wei, Wenjing; Houk, Kendall N.; Nelson, Hosea M.
• Is Part Of: Angewandte Chemie. Volume 134:Number 12(2022)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-02-03
• Subjects: Alkenyl Boronates -- Electrochemistry -- Fluorination -- Vinyl Carbocations -- Vinyl Fluorides; Chemistry -- Periodicals; 540
• DOI: 10.1002/ange.202113972
• Languages: English
• ISSNs: 0044-8249

Abstract

Abstract: The electrochemical generation of vinyl carbocations from alkenyl boronic esters and boronates is reported. Using easy‐to‐handle nucleophilic fluoride reagents, these intermediates are trapped to form fully substituted vinyl fluorides. Mechanistic studies support the formation of dicoordinated carbocations through sequential single‐electron oxidation events. Notably, this electrochemical fluorination features fast reaction times and Lewis acid‐free conditions. This transformation provides a complementary method to access vinyl fluorides with simple fluoride salts such as TBAF. Abstract : Vinyl carbocations were generated via single‐electron oxidation of alkenyl boronates using electrical potentials. This electrochemical process enabled the formation of these reactive species without the use of Lewis or Brønsted acids. The intermediate vinyl carbocations were trapped with nucleophilic fluoride sources to yield vinyl fluorides; the production of new C−C, C−Cl, and C−Br bonds was also demonstrated.