Unexpected formation of novel butenolides by thermolysis of o- carboranyl substituted cyclobutenones

Abstract

On thermolysis, o-carboranyl substituted 4-aryl-4- hydroxycyclobutenones 5a-d undergo electrocyclic ring opening followed by ring closure to yield substituted butenolides 6a-d This is in contrast to the thermolysis of cyclobutenones which generally produces substituted quinones.