Organophosphine-Promoted Decarbynylative Hydrocarbenylation of the Carbon-Carbon Triple Bond.

Herein, an innovative illustration of organophosphine-promoted decarbynylative hydrocarbenylation of diynoates with 2-oxindoles has been uncovered, affording (E)-3-alkyl/aryl propynylidene/allylidene oxindoles regio- and stereoselectively through the unique C≡C bond scission of diynoates. This tandem reaction proceeded via the initial nucleophilic α-attack of phosphines on diynoates, followed by a sequential process involving proton abstraction/nucleophilic attack, H-shift, and subsequent removal of the phosphorus ylide, enabling the formation of (E)-3-alkyl/aryl propynylidene/allylidene oxindoles with broad functional group tolerance. Additionally, the wide substrate scope (>50 entries), scalability, novel reaction mechanism, late-stage functionalization of some FDA-approved marketed drugs, metal-free C≡C bond scission, downstream transformations (>14 examples), and good to excellent yields (up to 92%) with excellent stereo- and regioselectivity are the remarkable features of this strategy.