Visible-Light-Induced External Oxidant-Free Oxidative Phosphonylation of C(sp²)–H Bonds

Abstract

Considering the synthetic value of phosphonates, developing powerful catalytic methods for the phosphonylation of C­(sp2)–H bonds is important. Herein, we achieve a visible-light-induced external oxidant-free oxidative phosphonylation of C­(sp2)–H bonds via the combination of photocatalysis and proton-reduction catalysis. Mechanistic studies indicate that the visible-light-induced electron-rich arene radical cation is the key reactive intermediate. The synthetic application of this approach is demonstrated in the late-stage functionalization of pharmaceutical molecules. This study may have significant implications for the functionalization of C­(sp2)–H bonds, especially for those that are sensitive to oxidative conditions.

Photochemical Strategies for Carbon–Heteroatom Bond Formation

“…This dual catalytic CDC approach was subsequently applied to the coupling of azoles ( 78 ) and alcohols ( 97 ) with alkenes ( 128 , Scheme , A)[54b] and for the etherification of arenes. [54c] The same catalytic system enables an oxidant‐free arylation of NH‐sulfoximines ( 131 , Scheme , B).…”

“…This dual catalytic CDC approach was subsequently applied to the coupling of azoles ( 78 ) and alcohols ( 97 ) with alkenes ( 128 , Scheme , A)[54b] and for the etherification of arenes. [54c] The same catalytic system enables an oxidant‐free arylation of NH‐sulfoximines ( 131 , Scheme , B). [54d] Stern–Volmer studies showed that both starting materials quench PC* and generation of both radical cations might be responsible for the C–N coupling.…”

“…[54c] The same catalytic system enables an oxidant‐free arylation of NH‐sulfoximines ( 131 , Scheme , B). [54d] Stern–Volmer studies showed that both starting materials quench PC* and generation of both radical cations might be responsible for the C–N coupling. The scope of this catalytic strategy was further expanded to the phosphonylation of C(sp 2 )–H[54f] bonds as well as N , N ‐dialkylanilines ( 133 , Scheme , C).…”

“…The scope of this catalytic strategy was further expanded to the phosphonylation of C(sp 2 )–H[54f] bonds as well as N , N ‐dialkylanilines ( 133 , Scheme , C). [54e]…”

Scalable Rhodium(III)‐Catalyzed Aryl C−H Phosphorylation Enabled by Anodic Oxidation Induced Reductive Elimination

“…[2] Deactivation can be avoided by either adding the phosphorus reagent slowly to the reaction mixture (Scheme 1a) [3] or employing a-hydroxyalkylphosphonate as am asked, slow-releasing phosphonating reactant (Scheme 1b,c). [6] Despite these significant advances, [7] the reported methods (Scheme 1a-d) require stoichiometric amounts of silver salts as oxidants and are inefficient in converting diarylphosphine oxides into triarylphosphine oxides,w hich are precursors to triarylphosphine ligands. [6] Despite these significant advances, [7] the reported methods (Scheme 1a-d) require stoichiometric amounts of silver salts as oxidants and are inefficient in converting diarylphosphine oxides into triarylphosphine oxides,w hich are precursors to triarylphosphine ligands.…”