Amidyl Radical Directed Remote Allylation of Unactivated sp³ C−H Bonds by Organic Photoredox Catalysis

Abstract

The development of visible‐light‐mediated allylation of unactivated sp3 C−H bonds is reported. The remote allylation was directed by the amidyl radical, which was generated by photocatalytic fragmentation of a pre‐functionalized amide precursor. Both aromatic and aliphatic amide derivatives could successfully deliver the remote C−H allylation products in good yields. A variety of electron deficient allyl sulfone systems could be used as δ‐carbon radical acceptor.

Site-selective remote C(sp3)–H heteroarylation of amides via organic photoredox catalysis

“…This strategy offers a marvelous pathway to selectively achieve mild C–H bond cleavage and C–X (X = halides) and C–N bond formation 19 . Furthermore, interrupted HLF reactions using electron-deficient alkenes 23–27 , vinyl boronic acids 28,29 , allyl sulfones 30 , allylic chlorides 31 , etc. 32,33 as carbon-centered radical traps open a new window for remote C(sp 3 )–C bond formation.…”

Chiral Piperidines from Acyclic Amines via Enantioselective, Radical-Mediated δ C–H Cyanation

“…However, recently, the first examples of d C-C formation have been enabled by intercepting this radical translocation to afford acyclic, d-functionalized amides. [11][12][13][14][15][16][17][18][19][20] Nonetheless, development of enantioselective methods for termination of an HAT pathway remains an ongoing challenge [21][22][23][24] -both for the classic d C-H amination as well as for recent interrupted methods for d C-H functionalization. In fact, with the exception of a single example of d C-H arylation from our lab (65% ee), 25 all known remote C-H functionalizations via N-radical relays are racemic.…”

Generation of Alkyl Radicals: From the Tyranny of Tin to the Photon Democracy

“…The amidyl radical formed upon fragmentation of 28 – 1 •– gave rise to a tertiary radical upon 1,5-HAT, allowing the remote allylation, forming 28 – 2 in 75% yield. 191 …”