Mn-Catalyzed Electrochemical Chloroalkylation of Alkenes.

The heterodifunctionalization of alkenes is an efficient method for synthesizing highly functionalized organic molecules. In this report, we describe the use of anodically coupled electrolysis for the catalytic chloroalkylation of alkenes-a reaction that constructs vicinal C-C and C-Cl bonds in a single synthetic operation-from malononitriles or cyanoacetates and NaCl. Knowledge of the persistent radical effect guided the reaction design and development. A series of controlled experiments, including divided-cell electrolysis that compartmentalized the anodic and cathodic events, allowed us to identify the key radical intermediates and the pathway to their electrocatalytic formation. Cyclic voltammetry data further support the proposed mechanism entailing the parallel, Mn-mediated generation of two radical intermediates in an anodically coupled electrolysis followed by their selective addition to the alkene.