 The three main enrolation methods, palladium-catalyzed buckwalt-hardwick-type reactions, copper-mediated almond-type and chaunlem-type enrolation reactions, have different advantages and disadvantages depending on the type of reaction needed. Palladium-catalyzed reactions are more efficient and tolerant of steric demands, but require additional ligands. Copper-mediated reactions are faster and less expensive, but require longer reaction times and are less tolerant of sterics. Finally, almond-type reactions are mild and provide access to complex ring structures, but they take longer and are less efficient.