Abstract
The reaction of 5,5-dimethylcyclohexane-1,3-dione with an acyclic nitrone in DMF or acetone affords a 1: 1 mixture of dimer 2,2'-(arylmethylene)-bis(3-hydroxy-5,5-dimethylcyclohex-2-enone) and tetramer 2,2',2 '',2'''-(1,2-diarylethane-1,1,2,2-tetrayl)tetrakis(3-hydroxy-5,5-dimethyl-cyclohex-2-enone). This unprecedented type of metal-free homocoupling of two molecules of the dimer to furnish the tetramer is believed to proceed via an oxidation/reduction process involving N-methylhydroxylamine.