Electroorganic Synthesis of 2,5-Dialkoxydihydrofurans and Pyridazines on Solid Phase Using Polymer Beads as Supports

Abstract

Electroorganic synthesis has defied application in SolidPhase Organic Synthesis (SPOS) so far. Typically more than 99.9% of the substrate molecules immobilized on a polymeric support are buried in the interior of the bead, and therefore are unable to undergo direct contact with a heterogeneous reagent such as an electrode. This intrinsic impediment for an electrochemical reaction can be overcome by the use of a redox mediator which shuttles electrons from the electrode to the polymer bound substrate molecules. This approach of indirect electroorganic synthesis was successfully applied for the 2,5-dialkoxylation of furans on solid phase. The oxidation products can be hydrolyzed and through condensation with hydrazine hydrate substituted pyridazines are produced in 50-65% overall yield.

Nickel‐Electrocatalyzed Synthesis of Bifuran‐Based Monomers

“…In this report, we demonstrated that furans are viable substrates in nickel‐catalyzed electrohomocouplings, despite their high reactivity in oxidative processes such as in anodic methoxylations, cyanations, and polymerizations [74–82] . The developed method could be applied to the synthesis of both 2,2′‐bifuran‐5,5′‐dicarboxylic acid dimethyl ester and 3,3′‐bifuran‐5,5′‐dicarboxylic acid dimethyl ester, which are key constituents in highly potential bio‐based bifuran polymers and bifuran‐furan co ‐polymers [28–30] .…”

“…In this report, we demonstrated that furans are viable substrates in nickel-catalyzed electrohomocouplings, despite their high reactivity in oxidative such as in anodic methoxylations, cyanations, and polymerizations. [74][75][76][77][78][79][80][81][82] The developed method could be applied to the synthesis of both 2,2'-bifuran-5,5'-dicarboxylic acid dimethyl ester and 3,3'-bifuran-5,5'-dicarboxylic acid dimethyl ester, which are key constituents in highly potential bio-based bifuran polymers and bifuran-furan copolymers. [28][29][30] Importantly, the electrolysis can be performed in the absence of sacrificial anodes, and the products can be recovered without chromatography by precipitation, which might facilitate the upscaling of the reaction.…”