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

Abstract

Dedicated to the memory of Christophe M. SaudanThe 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.