The Robinson annulation is an organic reaction used to convert a ketone and an unsaturated ketone to a ne using base. The mechanism begins with deprotonation with the base of the c-hydrogen of the ketone to form an enolate. The enolate then does a 1,4 addition to the conjugated olefin (Michael addition) ,which then abstracks a proton from water to form a ketone. Deprotonation of the other hydrogen with base forms another enolate which then does in intermolecular attack on the ketone group to give a cyclic alkoxy intermediate. Protonation of the alkoxy and a final elimination step result in the cyclohexanone product.