Anodic olefn coupling reactions: A mechanism driven approach to the development of new synthetic tools

Anodic cyclization reactions are intriguing synthetic transformations because they oxidize a normally nucleophilic olefin in order to reverse its polarity and generate a reactive radical cation intermediate that is then trapped by a second nucleophile. The loss of a second electron from the cyclic intermediate generated followed by either solvent trapping or another chemical transformation leads to a new product that has retained the functionality used to initiate the reaction. The presence of this functionality can be used to further transform the product in subsequent synthetic steps. The hypothesis that the reactions led to a radical at the terminating end of the cyclization was quickly supported with the substrates. For the vast majority of electrochemical reactions, it can be assumed that the electrons are transferred and that the desired reactive intermediate is made. What needs to be controlled is what happens to that reactive intermediate. That is accomplished by the same techniques used to control the chemistry of any reactive intermediate. The development and optimization of new electrochemical synthetic methods begins by getting the organic chemistry correct.