Photoredox-Catalyzed Synthesis of 3,3-Difluoro-γ-lactams via 1,5-Hydrogen Atom Transfer-Involved Alkyne
Lin Tang1,2, Fengjuan Jia1, Ge Lv1
1College of Chemistry and Chemical Engineering, Xinyang Normal University, Xinyang 464000, China.
Abstract:
This manuscript describes the application of a 1,5-hydrogen atom transfer strategy in photoredox-catalyzed hydrodifluoroalkylation of alkynes. The approach utilizes a sequential cascade process of difluoroalkylation, 1,5-hydrogen atom transfer, C(sp3)-N cleavage, and intramolecular condensation cyclization to accomplish efficient [3 + 2] cycloaddition of readily available propargylamines with halodifluoroacetates (or halodifluoroacetamides). The reaction allows for the selective construction of polysubstituted 3,3-difluoro-γ-lactams with good functional group tolerance, and further transformations of the resulting 3,3-difluoro-γ-lactams into different building blocks are also accomplished.
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