Electrosynthesis of diaryliodonium compounds

Abstract

Electrochemical process for preparing heterocyclic and mixed heterocyclic/carbocyclic diaryl iodonium salts using a single compartment and a carbon anode in a single process step. The process proceeds in the presence of a solvent such as acetic acid and an electrolyte such as sulfuric acid.

1 . An electrolytic process for the preparation of a heterocyclic or mixed heterocyclic/carbocyclic diaryliodonium salt comprising 
 (a) charging an electrolytic cell fitted with an anode and a cathode in a single compartment with a reaction mixture comprising an iodoaryl compound, an aryl compound, a stable electrolyte, and a solvent, and    (b) applying an electric potential to the cathode and anode under conditions to promote formation of the heterocyclic or mixed heterocyclic/carbocyclic diaryliodonium salt product.    
     
     
         2 . The process of  claim 1  wherein the electrolyte functions partially or totally as the solvent.  
     
     
         3 . The process of  claim 1  wherein said iodoaryl compound is a heterocyclic compound containing at least 4 carbon atoms and an oxygen, nitrogen, or sulfur atom or carbocyclic aromatic compounds containing 6 to 11 carbon atoms which must not decompose due to anodic oxidation or cathodic reduction.  
     
     
         4 . The process of  claim 1  wherein said aryl compound is a heterocyclic compound containing at least 4 carbon atoms and an oxygen, nitrogen, or sulfur atom or carbocyclic aromatic compounds containing 6 to 11 carbon atoms which must not decompose due to anodic oxidation or cathodic reduction  
     
     
         5 . The process of  claim 3  wherein said iodoaryl compound is selected from the group consisting of iodotoluene, iodobenzene, iodonaphthalene, substituted with 1 or more substituents.  
     
     
         6 . The process of  claim 4  wherein the aryl compound is thiophene, pyrrole, or furan with 1 or more substituents wherein the substituents may be more electron withdrawing than hydrogen.  
     
     
         7 . The process of  claim 1  wherein the solvent is acetic acid.  
     
     
         8 . The process of  claim 1  wherein the electrolyte comprises sulfuric acid  
     
     
         9 . The process of  claim 1  wherein the electrolyte is a compound of fluorine or phosphorous, sulfuric acid, or a combination thereof.  
     
     
         10 . The process of  claim 1  wherein the reaction mixture further comprises about 1 to 15% drying agent based on the total weight of the reaction mixture.  
     
     
         11 . The process of  claim 10  wherein the drying agent is acetic anhydride.  
     
     
         12 . The method of  claim 1  wherein the anode is composed of a material selected from the group consisting of carbon, platinum, nickel, tantalum, titanium, nickel-copper alloy, and vanadium.  
     
     
         13 . The process of  claim 12  wherein the carbon anode is a graphitic carbon anode.  
     
     
         14 . The process of  claim 1  wherein the contents of the cell are blanketed with an inert gas.  
     
     
         15 . The process of  claim 14  wherein the inert gas is nitrogen.  
     
     
         16 . The process of  claim 1  wherein the electrical potential may be constant or pulsed direct current or alternating current.  
     
     
         17 . An electrolytic process for the preparation of a heterocyclic or mixed heterocyclic/carbocyclic diaryliodonium salt comprising introducing into an undivided electrolytic cell fitted with an anode and a cathode a reaction mixture composed of a solvent, an iodoaryl compound, an aryl compound and an electrolyte; applying an electric potential to the cathode and anode to form heterocyclic or mixed heterocyclic/carbocyclic diaryliodonium salt product.