Chemo- and regio-divergent access to fluorinated 1-alkyl and 1-acyl triazenes from alkynyl triazenes. Issue 12 (15th February 2022)

• Record Type: Journal Article
• Authors: Tan, Jin-Fay; Bormann, Carl Thomas; Severin, Kay; Cramer, Nicolai
• Is Part Of: Chemical science. Volume 13:Issue 12(2022)
• Page Start: 3409
• Page End: 3415
• Publication Date: 2022-02-15
• Subjects: Chemistry -- Periodicals; 540.5
• DOI: 10.1039/d2sc00294a
• Languages: English
• ISSNs: 2041-6520

Abstract

Abstract : Three mild and operationally simple fluorination protocols convert 1-alkynyl triazenes either into attractive 1, 1, 2, 2-tetrafluoro alkyl triazenes, α-difluoro α-triazenyl ketones or α-difluoro acyl triazenes. Abstract : The 1, 1, 2, 2-tetrafluoroethylene unit is prevalent in bioactive molecules and functional materials. Despite being in principle a straightforward strategy to access this motif, the direct tetrafluorination of alkynes involves very hazardous or inconvenient reagents. Therefore, safer and convenient alternatives are sought after. We developed a mild and operationally simple perfluorination method converting 1-alkynyl triazenes into 1, 1, 2, 2-tetrafluoro alkyl triazenes, employing cheap and readily accessible reagents. Moreover, a judicious tuning of the reaction conditions enables access to α-difluoro triazenyl ketones. Complementary, electrophilic fluorination of alkynyl triazenes gives rise to the regioisomeric α-difluoro acyl triazenes. These three chemo- and regio-divergent protocols enable access to elusive fluorinated 1-alkyl and 1-acyl triazenes, thus expanding the chemical space for these unusual entities. Furthermore, several reaction intermediates and side products revealed insights on the reaction pathways that may be useful for further fluorination chemistry of alkynes.