Dearomative radical spirocyclization from N-ce:raghubenzyltrichloroacetamides revisited using a copper(I)-mediated atom transfer reaction leading to 2-azaspiro[4.5]decanes

An atom transfer radical dearomatizing spirocyclization from N-benzyltrichloroacetamides using CuCl regioselectively leads to 2-azaspiro[4.5]decadienes, in which the labile allylic chlorine atom is easily replaced by a hydroxyl group in aqueous medium or by quenching with methanol or allylamine. After oxidation of the target compound, the N-tert-butyl group can be removed from the resulting spirocyclohexanedienone.