Employment of a C(sp)-based nucleophile for photoinduced palladium-catalysed cross-coupling.

The development of efficient methods for C(sp)-C(sp) bond formation remains a longstanding challenge in synthetic chemistry, especially in palladium catalysis employing sterically bulky electrophiles. In this study, we present a novel approach for achieving C(sp)-C(sp) cross-coupling photoinduced palladium catalysis, employing cyclopropanols as masked C(sp)-nucleophiles. Leveraging the unique reactivity of photoexcited palladium, this protocol enables radical-mediated C(sp)-C(sp) coupling across a broad range of substrates including sterically hindered and functionally diverse alkyl halides under mild conditions. This method significantly expands the extent of palladium-catalysed cross-coupling for bond construction between sp-hybridized carbon units, providing streamlined access to structurally complex C(sp)-rich frameworks that are crucial for medicinal chemistry.