Ruthenium-Catalyzed Oxidative Cross-Coupling Reaction of Activated Olefins with Vinyl Boronates for the Synthesis of (E,E)-1,3-Dienes

Abstract

An oxidative cross-coupling reaction between activated olefins and vinyl boronate derivatives has been developed for the highly stereoselective construction of synthetically useful (E,E)-1,3-dienes. The highlight of this reaction is that exclusive stereoselectivity (only E,E-isomer) was achieved from a base-free, ligand-free, and mild catalytic condition with a less expensive [RuCl 2 (p-cymene)] 2 catalyst.

Diversification of (E,E)-1,6-Dioxo-2,4-Dienes for the Synthesis of (+)-Aspicillin, Isolaurepan, and β-Parinaric Acid

“…Thus, development of new chemical transformations using simple protocols and easily accessible starting materials that enable atom-economic and concise strategies for the efficient synthesis of bioactive molecules, pharmaceuticals, and complex molecular scaffolds is highly desirable. In addition to our ongoing interest in the field of natural product synthesis and development of novel synthetic protocols, we have recently reported a direct oxidative coupling of vinyl ketones and/or acrylates using a ruthenium-catalyzed protocol (Scheme ). This straightforward and atom-economical protocol provides efficient access to stereoselective synthesis of ( E,E )-1,6-dioxo-2,4-dienes, which are versatile precursors for a variety of synthetic transformations and widely found structural motifs in a diverse group of natural products .…”

Ruthenium-catalyzed stereo- and chemoselective oxidative coupling of vinyl ketones: efficient access to (E,E)-1,6-dioxo-2,4-dienes

“…1). The transition metal-catalyzed chelation-assisted oxidative C–H bond alkenylation on alkenes such as simple alkenes, 4 acrylamides, 5 enamides/enolates, 6 α-oxoketene dithioacetals, 7 and enol phosphates 8 has been developed for the synthesis of a series of valuable and functionalized 1,3-dienes. Also, the Loh group reported an efficient and straightforward method for the synthesis of functionalized ( Z , E )-muconate derivatives with good stereo- and chemoselectivities via oxidative C–H bond functionalization of acrylates, but a direct oxidative coupling reaction of easily accessible vinyl ketone via vinylic C–H bond activation was found to be challenging and also its substrate scope was limited to α-substituted acrylate derivatives.…”