In this review we provide selected recent examples of applications of microwave irradiation to carry out various transformations
accelerated by a variety of catalysts. In particular, here we present transition-metal-catalyzed transformations (with the application
of palladium, copper, rhodium and other metal-containing compounds), organocatalysis, heterogeneous catalysis, phase-transfer catalysis,
the application of solid-supported catalysts, the use of inorganic catalysts (bases, acids and salts) and ionic liquids, etc. Combination of
microwaves and catalysts represents an efficient and general pathway applicable in the syntheses and transformations of different organic
targets, especially heterocyclic and some other compounds. The emphasis is dedicated to those compounds containing a 2H-pyran-2-one
moiety in their structure and their subsequent transformations into (hetero)aromatic derivatives.