An efficient synthesis of 2,2′-arylmethylene bis(3-hydroxy-5,5-dimethy1-2-cyclohexene-1-one) and 1,8-dioxooctahydroxanthenes using ZnO and ZnO-acetyl chloride

2,2'-Arylmethylene bis(3-hydroxy-5,5-dimethyl-2-cyclohexene-1-one) 41-s produced from reaction between dimedone with various aldehydes in acetonitrile using ZnO as a catalyst; whereas in the presence of ZnO acetyl chloride catalysts the reaction is limited to give only 1,8-dioxo-octahydroxanthenes 3a-k in very good yields. (C) 2010 Malek Taher Maghsoodlou. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.