The Danheiser benzannulation is a regiocontrolled phenol annulation. Successful preparation of compounds using the Robinson annulation methods have been reported. Examples are the Robinson annulation, Danheiser annulation and certain cycloadditions. CHC(O)CH=CH, which is useful in the Robinson annulation reaction. Specifically, the synthesis of cortisone is completed through the use of the Robinson annulation. Alkynyl thioethers and ynamines have been used as reactants in the annulation reaction. A common synthetic annulation reaction is the Robinson annulation. Trimethylenemethane cycloaddition is the formal [3+2] annulation of trimethylenemethane (TMM) derivatives to two-atom pi systems. Other research interests include the bridged Robinson annulation and the mixed Lewis acid Diels-Alder process. Asymmetric synthesis of Robinson annulation products most often involve the use of a proline catalyst. An efficient one-pot route entails annulation of cyclopentadiene with unsaturated C-synthons. Dichloromethane, chloroform, and 1,2-dichloroethane, are all appropriate solvents for the annulation reaction. A classical tandem sequence of Michael and aldol additions is the Robinson annulation. The Robinson annulation is a chemical reaction used in organic chemistry for ring formation. Oxidative annulation of alkenols to form six-membered rings may be accomplished with PCC.