C(sp 3 )-C(sp 3 ) bond formation via nickel-catalyzed deoxygenative homo-coupling of aldehydes/ketones mediated by hydrazine.

Aldehydes and ketones are widely found in biomass resources and play important roles in organic synthesis. However, the direct deoxygenative coupling of aldehydes or ketones to construct C(sp ³ )-C(sp ³ ) bond remains a scientific challenge. Here we report a nickel-catalyzed reductive homo-coupling of moisture- and air-stable hydrazones generated in-situ from naturally abundant aldehydes and ketones to construct challenging C(sp ³ )-C(sp ³ ) bond. This transformation has great functional group compatibility and can suit a broad substrate scope with innocuous H ₂ O, N ₂ and H ₂ as the by-products. Furthermore, the application in several biological molecules and the transformation of PEEK model demonstrate the generality, practicability, and applicability of this novel methodology.