Visible-Light-Induced Atom Transfer Radical Addition and Cyclization of Perfluoroalkyl Halides with 1,n-Enynes

Abstract

A mild and efficient visible-light-induced atom transfer radical addition and cyclization of 1,n-enynes (n = 6, 7) with perfluoroalkyl halides, leading to halo-perfluorinated N-heterocycles, has been developed. This protocol offers a mild, completely atom-economic, and general access to perfluorinated 2,4-dihydronquinolin-2­(1H)-ones and pyrrolidines from corresponding benzene and N-tethered 1,n-enynes (n = 6, 7) via 5∼6-exo-dig cyclization, allowing for the expedient incorporation of a wide variety of perfluorinated groups, such as CF3, i/n-C3F7, n-C4F9, n-C6F13, n-C8F17, n-C10F21, CF2Br, CF2CO2Et, etc. In addition, the reactions using 1,7-enynes (n = 6, 7) bearing a tert-butyl-linked alkynyl moiety enable a divergent cyclization involving a hydrogen atom transfer (HAT) process, thereby leading to novel α,α-halo-perfluorinated 2,4-dihydronquinolin-2­(1H)-ones.

Recent Advances in Photoinduced Perfluoroalkylation Using Perfluoroalkyl Halides as the Radical Precursors

“…Recently, photocatalytic ATRA reactions via 1,2-addition have been extensively reported, whereas the ATRA reactions of 1,n-enynes (n = 4, 6, 7), involving a remote 1,n-addition pattern (n > 2), is less exploited. In 2019, Tang and co-workers 35 developed a photoinduced chemo-and regioselective ATRA/cyclization between 1,n-enynes (n = 6, 7) and perfluoroalkyl halides (Scheme 10). In these reactions, benzene or N-tethered 1,n-enynes (n = 6, 7) underwent smooth ATRA reactions R f -X leading to various perfluorinated 3,4-dihydroquinolin-2(1H)-ones and pyrrolidines.…”

Photocatalytic Annulation‐Carbohalogenation of 1,7‐Enynes for Atom‐Economic Synthesis of Functionalized 3,4‐Dihydronaphthalen‐1(2H)‐ones

“…Next, the radical addition of the intermediate A to the C=C bond of 1,7‐enynes 1 produced alkyl radical B , followed by 6‐ exo‐dig cyclization yielded the E ‐intermediate C as the major stereoisomers and the Z ‐intermediate C’ as minor stereoisomers, which is probably due to the steric hindrance effect. The resulting X − was then oxidized by Ir(IV) species to provide the X radical [17e,21] and regenerate Ir(III) complex. Finally, the radical cross‐coupling between C / C ’ and the X radical afforded the desired products 3 with stereoselectivity.…”

Visible-light-promoted and chlorophyll-catalyzed aerobic desulfurization of thioamides to amides

“…In the past decade, visible light photoredox catalysis has become a powerful tool for green organic synthesis due to its sustainability, mild reaction conditions and the potential application of visible light. 1 …”