Cross‐Coupling of Organyl Halides with Alkenes: the Heck Reaction

Abstract

The carbopalladation of an alkene by an organylpalladium halide is the essential step in one of the major contemporary metal-catalyzed C-C-coupling reactions. About 35 years ago, a Japanese and an American group almost simultaneously designed and executed palladium-mediated coupling reactions of aryl and alkenyl halides with alkenes [1]. In subsequent investigations, Richard Heck and his group developed this reaction into a catalytic transformation and started to demonstrate its usefulness as well as its rather broad scope. The real push to utilize this powerful C-C bond-forming process, however, started only around the mid-1980s, and by now an impressive number of publications has established the meanwhile socalled Heck reaction [2] as an indispensable method in organic synthesis [3]. The applications range from the preparation of hydrocarbons, novel polymers and dyes to new advanced enantioselective syntheses of natural products and biologically active non-natural compounds. The more or less simultaneous developments of mechanistically related variants, namely the Suzuki, Stille, Hiyama, Kumada and Negishi coupling reactions (see Chapters 2, 3, 4, 12 and 15 in this book, respectively) of metallated alkenes and arenes with aryl and alkenyl halides or the metal-catalyzed formation and cycloisomerization of enynes have drawn profit from the improvement of and mechanistic insights into the Heck reaction. This, of course, also applies vice versa. Using only a catalytic amount of a palladium(0) complex or a precursor to a palladium species, the Heck reaction can bring about unprecedented structural changes, particularly when conducted intramolecularly. The full potential of this palladium-catalyzed process is still being further explored, as demonstrated by a total of 2400 relevant publications during the past 10 years, and a continuous annual growth in publications of 15 % per year. Therefore, it is appropriate to say that the Heck reaction is one of the true "power tools" in contemporary organic synthesis [4], competing favorably with the Diels-Alder reaction (25 000 references), olefin metathesis (1500 references), Wittig reaction (15 000 references), or Claisen rearrangement (15 000 references). Scheme 5-1 Mechanism of the Heck reaction [7]. Pd(OTfa) 2 , P(2-furyl) 3 , iPr 2 EtN; Pd(OTfa) 2 or Pd(F 6 -acac) 2 ] and fluorinated phosphanes [90] [91]

Palladium-Catalyzed Cross-Coupling Reactions: A Powerful Tool for the Synthesis of Agrochemicals

“…Furthermore, the application of a diazonium salt instead of an arylhalide reduces the amount of salts generated, allowing for a particularly green reaction. This work, one of the few examples of a Pd-catalyzed coupling reaction working on an industrial scale, highlights the power of diazonium chemistry for process chemists. ,, …”

Constructing Bridges between Computational Tools in Heterogeneous and Homogeneous Catalysis

“…This is illustrated by recent work on OA of aryl-halide bonds to Au(I) complexes, leading to Au(III)(aryl)(halide) complexes, which is a difficult reaction to achieve, compared with the facile OA of aryl-halides to Pd(0). 74 Bickelhaupt showed that the energy barrier for OA of aryl-halides to Au(I) catalysts based on a linear L-Au-L geometry is due to the energy penalty associated with deformation of the linear framework into a bent framework (see Figure 9). 75 At the same time, Au(I) complexes containing chelating diphosphines with small bite angles, thus already deformed towards the bent geometry that they will assume in the oxidative addition transition state/product, perform OA of phenyl iodide to Au(I) at low temperature.…”

Matsuda–Heck reaction with arenediazonium tosylates in water

“…Typically, alcohols, THF or DMF are used as solvents for Matsuda–Heck reactions. One of the most rapidly developing trends in organic synthesis is the carrying out of reactions in water following a «Green chemistry» approach [ 4 ]. In 2012, examples of the Matsuda–Heck arylation of styrene and acrylic acid esters with arenediazonium tetrafluoroborates in water and catalyzed with in situ formed Pd nanoparticles [ 5 ] or agarose-supported Pd nanoparticles [ 6 ] have been reported.…”