Novel electrochemical reactivity of Ni(cyclam)Br₂: catalytic carbon dioxide incorporation into epoxides

Abstract

Cyclic carbonates are obtained in good yields from terminal epoxides and carbon dioxide in an electrochemical nickel-catalysed reaction.

Carbon−Carbon Bond Formation with Electrogenerated Nickel and Palladium Complexes

“…[95] Thus, CO 2 incorporation into 2-haloaryl epoxides led chemoselectively to carboxylated products that varied according to the nature of the substrate and of the catalytic system (Scheme 17). Whereas terminal epoxides lead to cyclic carbonates in good yields, [96] 1,1-disubstituted epoxides react first through electrocarboxylation of a carbonϪhalogen bond followed by an oxirane ring opening. Five-membered-ring benzolactones were selectively formed with cyclam as the ligand on nickel, whereas six-membered-ring isocoumarin derivatives were obtained using 2,2Ј-bipyridine (Scheme 17).…”

Nickel-catalyzed electrochemical carboxylation of epoxides: mechanistic aspects

“…The electrochemical method allows the efficient transformation of terminal epoxides into cyclic carbonates under very mild conditions, according to Eqn [1]:…”

“…1 These are important synthons for the preparation of functionalized organic intermediates, such as 1,2-diols, 2 and for the synthesis of various polymeric materials. 3 Their preparation from CO 2 as a C 1 building block (instead of phosgene) constitutes an interesting alternative based on the use of non-toxic, abundant and cheap starting material.…”

Ionic Liquids in Green Carbonate Synthesis

“…Electrochemical synthesis of cyclic carbonates from CO 2 with epoxides, anilines, alcohols, and glycols was reported [53][54][55][56][57][58][59][60]. For example, Duñach et al [54] conducted the reaction of epoxides with CO 2 to the corresponding cyclic carbonates by an electrochemical method in the presence of nickel(II) complexes.…”