Multimetallic Ni- and Pd-Catalyzed Cross-Electrophile Coupling To Form Highly Substituted 1,3-Dienes

Abstract

The synthesis of highly substituted 1,3-dienes from the coupling of vinyl bromides with vinyl triflates is reported for the first time. The coupling is catalyzed by a combination of (5,5'-bis(trifluoromethyl)-2,2'-bipyridine)NiBr and (1,3-bis(diphenylphosphino)propane)PdCl in the presence of a zinc reductant. This method affords tetra- and penta-substituted 1,3-dienes that would otherwise be difficult to access and tolerates electron-rich and -poor substituents, heterocycles, an aryl bromide, and a pinacol boronate ester. Mechanistically, the reaction appears to proceed by an unusual zinc-mediated transfer of a vinyl group between the nickel and palladium centers.

Stereoselective Synthesis of (Z)‐β‐Enamido Triflates and Fluorosulfonates from N‐Fluoroalkylated Triazoles

“…Since the first report in the late 1960s, trifluoromethanesulfonates (triflates) have become the subject of numerous studies not only as precursors of vinyl cations but also as substrates in transition‐metal‐catalyzed C−C bond‐forming reactions . Recently, the synthetic community has been witnessing a renewed interest in transformations involving vinyl cations .…”

“…Since the first report in the late 1960s, [1,2] trifluoromethanesulfonates( triflates) have become the subjecto fn umerouss tudies not only as precursors of vinyl cations [3][4][5][6] but also as substrates in transition-metal-catalyzed CÀCb ond-forming reactions. [7][8][9][10][11] Recently,t he synthetic community has been witnessing ar enewed interest in transformations involving vinyl cations. [12,13] Despite the valuables ynthetica pplicationso fv inyl triflates,they possess some drawbacks that limit their industrial application.F or instance, they are commonly liquids, sensitive to hydrolysis and their preparation requires expensiver eagents.…”

Modern Synthetic Methods for the Stereoselective Construction of 1,3-Dienes

“…Even if the use of lithium organometallics is advantageous, it is obvious that the best alternative would be to avoid completely the use vinylic organometallic reagents as starting materials. In this regard, Olivares and Weix described the synthesis of 1,3-dienes by the means pf Ni/Pd cooperative catalysis in the presence of zinc as reductant to afford tetra- and penta-substituted 1,3-dienes in good yields ( Scheme 13 ) [ 70 ].…”

Pd‐Catalyzed Synthesis of Vinyl Arenes from Aryl Halides and Acrylic Acid

“…[27] The synthetic value of vinyl arenes is illustrated by the follow-upr eactions summarized in Scheme 4. [27] The synthetic value of vinyl arenes is illustrated by the follow-upr eactions summarized in Scheme 4.…”

“…The reactionc an also be used for the vinylation of alkenyl bromides, providing convenienta ccess to valuable dienyl arenes (Scheme3). [27] The synthetic value of vinyl arenes is illustrated by the follow-upr eactions summarized in Scheme 4. Vinyl arene 3y was synthesized from the corresponding aryl bromide in 70 % yield on gram scale and was then furtherd erivatized through hydroxythiolation, hydroxyacyloxylation, and nitration.…”