Carbon–Halogen Bond Formation by the Reductive Elimination of Pd^II Species

Abstract

It is well known that Pd 0 undergoes oxidative addition to organic halides, especially aryl or vinyl halides. In the contrast, the formation of organic halides by reductive elimination of RPd II X (X= halogen) has been mostly ignored until very recently. This Focus Review discusses recent developments in palladium-catalyzed carbon-halogen bond formation by the reductive elimination of RPd II X. These new developments have enriched the scope of palladium-catalyzed reactions, and provide a new way to construct carbon-halogen bonds.

An Exclusively trans‐Selective Chlorocarbamoylation of Alkynes Enabled by a Palladium/Phosphaadamantane Catalyst

“…The palladium-catalyzed carbohalogenation of unsaturated CÀCbonds has emerged as arobust method for the synthesis of organic halides. [1] Although significant advances in the area of alkene carbohalogenation have been demonstrated, [2] reports using alkynes remain scarce. [3] To this end, we recently described as tereodivergent Pd-catalyzed alkyne carbohalogenation reaction using aryl halides,w hich relied on the combined steric bulk of both catalyst and substrate to promote the desired reactivity (Scheme 1a).…”

Transition‐Metal‐Catalyzed Carbohalogenative 1,2‐Difunctionalization of C−C Multiple Bonds

“…Among divergent 1,2-difunctionalization processes, synthesis of organohalides by 1,2-difunctionalization of alkenes and alkynes have become an area of emerging significance. Over the past decade, transition metal, [12] non-metal or photoredox catalyzed, [13] inter and intramolecular 1,2-carbohalofunctionalization of carboncarbon multiple bonds, involving the breakage of a pre-existing carbon-halogen (CÀ X) bond and subsequent formation of a new CÀ C and CÀ X bond, have been reported highlighting the mildness of the reaction conditions, the avoidance of stoichiometric waste of by-products, and improved levels of chemo-, regioand stereoselectivities.…”

Palladium(0)‐Catalyzed Iminohalogenation of Alkenes: Synthesis of 2‐Halomethyl Dihydropyrroles and Mechanistic Insights into the Alkyl Halide Bond Formation

“…Recently, the advances on palladium(0)-catalyzed synthesis of organic halides provide a new conceptual alternative, which enables the formation of carbon-halide bonds by the highly endothermic carbon halide reductive elimination (RE) from a palladium(II) species. [2] Since 2009, the group of Buchwald has developed elegant palladium(0)-catalyzed systems to realize the conversion of aryl triflates into aryl halides, including ArBr and ArCl, as well as ArF [Scheme 1, Eq. (1)].…”