Photoinduced Remote C(sp3)-H Phosphonylation of Amides

The present study reports an unprecedented protocol for the phosphonylation of unactivated C(sp3)-H bonds. By utilizing 1 mol % 4DPAIPN (1,2,3,5-tetrakis(diphenylamino)-4,6-dicyanobenzene) as the catalyst, satisfactory yields of γ-phosphonylated amides are obtained through a visible-light-induced reaction between N-((4-cyanobenzoyl)oxy)alkanamides and 9-fluorenyl o-phenylene phosphite at room temperature. This protocol demonstrates broad substrate scope and wide functional group compatibility.

Ruthenium-Catalyzed Remote-Difunctionalization of Nonactivated Alkenes for Double meta-C(sp2)-H/C-6(sp3)-H Functionalization

Twofold distal C-H functionalization was accomplished by difunctionalization of nonactivated alkenes to provide rapid access to multifunctionalized molecules. We, hence, report the multicomponent ruthenium-catalyzed remote 1,n-difunctionalization (n = 6,7) of nonactivated alkenes with fluoroalkyl halides and heteroarenes in a modular manner. The meta-C(sp2)-H/C-6(sp3)-H distal functionalization featured mild conditions, unique selectivity, and broad substrate scope with a domino process for twofold remote C(sp2)-H/C(sp3)-H activation of the sequential formation of three different carbon-centered radicals. A plausible mechanism was proposed based on detailed experimental and computational studies.

C-H Bond Activation Relay (CHAR) of Proline Ester Derivatives Promoted by In Situ Triarylamine Radical Cation: Selective Synthesis of 4-Bromopyrrole Derivatives

Using the in situ generated triarylamine radical cation as an initiator, the sp³ C-H bond of proline esters was smoothly oxidized and brominated through C-H activation relay (CHAR), giving a series of 4-bromopyrroles in good yields with high regioselectivity. The mechanistic study revealed that the oxidation of the active C-H bond initiated the followed 1,5-HAT and bromination, which provides a new method to realize the functionalization of the remote C-H bond.