A SYNTHESIS OF HIGHLY SUBSTITUTED AROMATICS THROUGH REGIOCONTROLLED CONSTRUCTION OF CYCLOBUTENONES BEARING UNSATURATED SUBSTITUENTS AT THE 4-POSITION

2,3-Substituted 4-chloro-2-cyclobutenones, prepared by regiospecific transformations of substituted cyclobutenediones, undergo palladium-catalyzed cross-coupling with vinyl- and arylstannanes and vinylzirconium reagents to form 4-R(unsat)-2-cyclobutenones. On thermolysis (100-degrees-C), these substrates transform into substituted phenols in high yield. A pentasubstituted aromatic and a variety of tri- and tetrasubstituted aromatic compounds were prepared in a regiospecific fashion using this chemistry.