Ligandless, Anionic, Arylpalladium Halide Intermediates in the Heck Reaction

Anionic Pd(0) and Pd(II) intermediates in palladium-catalyzed Heck and cross-coupling reactions.

The anions of PdCl(2)L(2) and Pd(OAc)(2), precursors of palladium(0) used in cross-coupling and Heck reactions, play a crucial role in these reactions. Tricoordinated anionic complexes Pd(0)L(2)Cl(-) and Pd(0)L(2)(OAc)(-) are the effective catalysts instead of the usually postulated Pd(0)L(2) complex. The anion ligated to the palladium(0) affects the kinetics of the oxidative addition to ArI as...

Heck-type arylation of 2-cycloalken-1-ones with arylpalladium intermediates formed by decarboxylative palladation and by aryl iodide insertion.

[reaction: see text] A palladium-catalyzed decarboxylative arylation reaction was shown to produce Heck-type coupling products using a number of different arene carboxylic acid and 2-cycloalken-1-one substrates. The more conventional Heck coupling of an aryl iodide and a 2-cycloalken-1-one reactant was also briefly explored for comparison, where it was found that phosphine-free (Jeffery) condit...

Regioselective Heck reaction of aliphatic olefins and aryl halides.

A regioselective Heck reaction of aliphatic olefins and aryl bromides is realized at internal carbons of olefins. Methanol solvent promoted halide ionization from neutral arylpalladium halide complexes via hydrogen bonding, so as to create cationic aryl-Pd species for regioselective olefin insertion.

Mechanisms of the Mizoroki–Heck Reaction

The palladium-catalysed Mizoroki–Heck reaction is the most efficient route for the vinylation of aryl/vinyl halides or triflates. This reaction, in which a C C bond is formed, proceeds in the presence of a base (Scheme 1.1) [1, 2]. Nonconjugated alkenes are formed in reactions involving cyclic alkenes (Scheme 1.2) [1e, 2a,c,e,g] or in intramolecular reactions (Scheme 1.3) [2b,d–g] with creation...

NMR Spectroscopic Analyses of Anionic Reactive Intermediates