Robinson annulation is a chemical reaction that combines a cyclohexenone with a ketone or aldehyde to form a complex bicyclic compound. This process typically involves a series of steps, including an initial Michael addition followed by an intramolecular aldol condensation. The reaction is named after the chemist Sir Robert Robinson, who contributed significantly to organic chemistry. The resulting bicyclic structure is valuable in the synthesis of various natural products and pharmaceuticals. Robinson annulation is particularly useful because it allows for the construction of multiple rings in a single reaction, making it an efficient method in organic synthesis.