ChemInform Abstract: Copper‐Catalyzed Cyclization of N‐Allylhalodifluoroacetamides: An Efficient Synthesis of α,α‐Difluorinated γ‐Lactams.

Abstract

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Solvent-Controlled Switchable Synthesis of gem-Difluoro Compounds from Anhydrides under Photoredox Catalysis

“…Further substrate expansion to crucial functional groups was also examined to obtain the corresponding lactams and lactones with fluorinated ether (21), amide (22,53), ester (23), and ethers (39, 40) moiety. β-Substituted styrenes with phenyl (24), methyl (25,52), and oxazolidine (53) underwent the desired transformation successfully, giving the corresponding cyclic adducts in decent yields and very high diastereoselectivity (>99:1). The structures of lactams 1 and 24 were demonstrated by X-ray crystallography.…”

“…Immediate activation of CDFAA to originate gem-difluoro radical intermediates would be an atom-and step-economic strategy to synthesis diverse fluorinated molecules from fundamental feedstock. In this context, the synthesis of gem-difluoro-γ-lactams and lactones has been a topic of interest of many researchers while demonstrating their preparation via transition-metal catalyzed radical cascade cyclization reactions [52][53][54] , oxidative intramolecular cyclizations, 55 and intramolecular esterification of olefins. 56 Although these methods provide routes to access fluorinated ring systems, the incorporation of the gem-difluoro group or a surrogate moiety via a multi-step synthetic sequence is often required prior the cyclization.…”

Solvent-Controlled Switchable Synthesis of gem-Difluoro Compounds from Anhydrides under Photoredox Catalysis

“…Further substrate expansion to crucial functional groups was also examined to obtain the corresponding lactams and lactones with fluorinated ether (21), amide (22,53), ester (23), and ethers (39, 40) moiety. β-Substituted styrenes with phenyl (24), methyl (25,52), and oxazolidine (53) underwent the desired transformation successfully, giving the corresponding cyclic adducts in decent yields and very high diastereoselectivity (>99:1). The structures of lactams 1 and 24 were demonstrated by X-ray crystallography.…”

“…Immediate activation of CDFAA to originate gem-difluoro radical intermediates would be an atom-and step-economic strategy to synthesis diverse fluorinated molecules from fundamental feedstock. In this context, the synthesis of gem-difluoro-γ-lactams and lactones has been a topic of interest of many researchers while demonstrating their preparation via transition-metal catalyzed radical cascade cyclization reactions [52][53][54] , oxidative intramolecular cyclizations, 55 and intramolecular esterification of olefins. 56 Although these methods provide routes to access fluorinated ring systems, the incorporation of the gem-difluoro group or a surrogate moiety via a multi-step synthetic sequence is often required prior the cyclization.…”