1,3,4-Oxadiazoles, standing for a class of five-membered heterocyclic compounds with multiple heteroatoms, show anti-inflammatory, anti-convulsant, anti-inositol and other biological activities. They also served as important intermediates in organic synthesis. Thus, the development of general and straightforward methods for their synthesis is of great significance. In this paper one-step synthesis of non-symmetric 2,5-disubstituted 1,3,4-oxadiazole derivatives with good yield was completed under electrocatalytic conditions by using cheap and readily available aldehydes and hydrazides as starting materials. Their structures were confirmed by IR, ¹H NMR, ¹³C NMR and HRMS analyses. The reaction features mild conditions, high atom-economy and wide substrate scope, providing a green and sustainable synthetic protocol for constructing 1,3,4-oxadiazole skeleton.

Thiocyanate, as a versatile synthon, which has important application value in many fields such as pharmaceutical, pesticide and materials. The photocatalytic and electrocatalytic thiocyanation reactions have been widely concerned in organic chemistry due to the advantages of green, efficiency and safety. In this review, the cross-coupling/thiocyanation reactions based on the photocatalytic and electrocatalytic are described, which is expected to be helpful in exploring the green synthesis of thiocyanates compounds.

The electro-oxidation cyanation of p-methoxybenzyl alcohol (p-MeOC₆H₄CH₂OH) to prepare aryl nitriles was studied by using cyclic voltammetry (CV) and constant current electrolysis (CCE). The effects of the volume ratio of H₂O, concentration of H₂SO₄, temperature, electrode materials, current density and solvents on the electro-chemical reaction were studied. The results showed that the yield of p-methoxylbenzonitrile (p-MeOBN) was 90% in 0.15 mol·L^-1 H₂SO₄ and 30% H₂O-DMSO solution at 60℃ and 10 mA/cm² of current density when tetrabutylammonium perchlorate (Bu₄NClO₄) was used as electrolyte. The CCE of aromatic benzyl alcohols with different p-and o-substituted analogs was investigated under the optimized reaction conditions, and the yields toward formation of the corresponding aryl nitriles were 61%~92%. A plausible mechanism for the electro-oxidation cyanation procedure was proposed. A novel paired electrochemical method for the synthesis of aryl nitriles from aromatic benzyl alcohols with hydroxylamine (HAM) as "N" source and aldehyde in situ in undivided electrochemical cell was successfully developed.

Anodic oxidation of aryl iodine compouds is a green and efficient method for the synthesis of hypervalent iodine reagents. This method replaces chemical reagents with electric current, avoiding the use of expensive and handle difficult oxidants such as m-CPBA, H₂O₂, oxone, selectfluor etc. Electrochemically generated hypervalent iodine reagents can not only promote fluorination, oxidative cyclization, but also be successfully applied in the total synthesis of natural products. In addition, recyclable aryl iodine mediator can be used to indirect anodic fluorination and easily separated from products. The organic electrochemical synthesis of hypervalent iodine reagents and their applications in various chemical transformations are reviewed.

An electrochemical synthesis of tetrasubstituted hydrazines through dehydrogenative dimerization of secondary amines has been developed. The reactions are conducted in a simple undivided cell with constant current. The use of electricity to promote the reactions obviates the need for transition metal catalysts and oxidizing reagents, providing an efficient and sustainable access to tetrasubstituted hydrazines with diverse electronic properties.

Carbon-hydrogen bonds are the most extensive and basic chemical bonds existed in organic compounds. Electrochemical functionalization and direct conversion of aromatic C—H bonds is a green, sustainable, and atomically economical transformation pathway, which avoids the pre-functionalization of reactants. The anodic electrooxidation of aromatics allows the formation of C—X (X=C, N, O, S) bonds and the preparation of fused aromatic rings without the use of oxidants. Certain C—H activation reactions with chemoselectivity and regioselectivity can also be achieved by the optimization of electrode materials, electrolytes, and solvents. Vourious reactions focusing on the electrochemical functionalizations of C—H bonds in aromatic compounds are mainly reviewed.