Rhodium-Catalyzed [2+2+2] Cycloaddition for the Synthesis of Substituted Pyridines, Pyridones, and Thiopyranimines

A review. The transition-metal-catalyzed [2+2+2] cycloaddn. of alkynes with nitriles is a useful and atom-economical method for the synthesis of substituted pyridines. The use of isocyanates and isothiocyanates in place of nitriles affords substituted pyridones and thiopyranimines, resp. This review comprehensively covered the [2+2+2] cycloaddn. reactions catalyzed by rhodium complexes for the synthesis of substituted pyridines, pyridones, and thiopyranimines. Asym. variants of these rhodium-catalyzed [2+2+2] cycloaddn. reactions are also described. [on SciFinder(R)]