Highly Selective Rhodium Catalyzed 1,4‐Hydrogenation of Conjugated Dienals

Abstract The combination of a large bite‐angle diphosphine with a neutral rhodium complex in presence of a weak base has enabled the regio‐ and chemoselective hydrogenation of the α,β‐carbon‐carbon double bond of conjugated dienals in high selective fashion. This methodology offers a mild and neutral alternative to the commonly employed Claisen rearrangement in the synthesis of γ,δ‐unsaturated aldehydes. A large variety of substituted α,β,γ,δ‐bis‐unsaturated aldehydes has been selectively hydrogenated with the catalyst described herein showing the potential of this new methodology.