Current Research in Green and Sustainable Chemistry (Jan 2022)
Electro-organic conversions: A review on electrocatalysis of Heck reactions
Abstract
The electrosynthesis methods are cheaper and greener route as electrons are used as a source of reagent to carry out redox reactions. The addition or removal of electrons to/from an organic molecule generates an active molecule which is transformed into products. With the availability of commercial reaction cells, electrodes, and power supplies modern synthesis laboratories seek alternative electrochemical assisted synthesis pathways for organic transformations. The review paper covers brief introduction of electro-organic conversions to the readers followed by its recent development and its present status in Heck electrocatalysis. The reaction of an olefin with aryl or vinyl halide is known as the Heck reaction and is an important tool in organic synthesis. Traditional heck catalysis suffers from the polymerization of an active Pd(0) to inactive palladium black that leads to loss of catalysis with time. An electrochemical technique offers the advantage of regenerating true active Pd(0) species under the circulation of current. Under electrolysis there is a continuous and steady generation of active catalyst concentration which is beneficial for the overall yield of the reaction. Different Pd, Ni, and Co catalysts that were explored in Heck electrochemical process are discussed, focus is put on the in-situ electrochemical generation of true catalytic active species. Electrochemical Heck reaction is an emerging area and exhibits enhanced catalytic efficiency and with improved technique scopes to in-depth mechanistic sights.
