Electrochemically Induced Synthesis of -Allyloxyphthalimides via Cross-Dehydrogenative C-O Coupling of -Hydroxyphthalimide with Alkenes Bearing the Allylic Hydrogen Atom.

The electrochemically induced reaction between alkenes, bearing an allylic hydrogen atom, and -hydroxyphthalimide was investigated. Cross-dehydrogenative C-O coupling with phthalimide--oxyl radical, derived from -hydroxyphthalimide, occurs instead of oxidation of the allylic site, with the formation of a carbonyl group or functionalization of the double C=C bond. The discovered transformation proceeds in an undivided electrochemical cell equipped with a carbon felt anode and a platinum cathode. Coupling products were obtained with yields up to 79%. The developed process is based on the abstraction of hydrogen atom from the allylic position for functionalization while the C=C bond remains unreacted. The method exploits the ability of the phthalimide--oxyl radical to abstract hydrogen atoms with the following interception of the intermediate -centered radical.