Silver‐Catalyzed Vinylogous C(sp ³ )–C(sp ³ ) Coupling of Bicyclo[1.1.0]Butanes With Vinylcarbenes

Owing to the intrinsically high reactivity of the carbenoid center, the vinylogous reactivity of metallovinylcarbenes—specifically the selective construction of quaternary alkyl–allyl bonds—remains largely underexplored in organic synthesis. We herein describe the first silver‐catalyzed vinylogous C(sp 3 )–C(sp 3 ) cross‐coupling of bicyclo[1.1.0]butanes (BCBs) with in situ‐generated vinylcarbenes from vinyl triftosylhydrazones. This reaction proceeds under mild conditions, furnishing diverse allyl‐substituted cyclobutenes containing a quaternary carbon center with high yields, excellent regioselectivity, and diastereoselectivity. Further derivatization of the cyclobutene derivatives verifies their role as versatile synthetic linchpins for various downstream synthetic operations. Mechanistic studies combined with DFT calculations clarify an unprecedented γ‑addition of BCBs to silver vinylcarbene, followed by a 1,5‐proton transfer pathway, revealing the fundamental basis for the exclusive regio‐ and diastereoselectivity of this transformation.