In this diploma syntheses of selected 6-substituted and 5,6-disubstituted 3-benzoylamino-2H-pyran-2-ones, an example of the deprotection and protection of an amine group on 2H-pyran-2-one and the synthesis of bicyclo[2.2.2]octene aducts are presented. As part of my work, I applied different synthetic methods for 2H-pyran-2-ones preparation. As a part of the synthesis of double cycloaducts, I have explored various methods that could yield the final product. Thus, in the experimental part, I wanted to find out how the use of microwave irradiation and high pressure in synthesis turns out in comparison to the more conventional, but less green methods (harmful solvents, reflux). I followed the reaction conversions by TLC and spectroscopic methods (IR, 1H NMR, HRMS). Under the conditions applied, the desired double cycloaducts were obtained only under conventional heating (reflux). The removal and introduction of the amine protection group and the synthesis of 2H-pyran-2-ones were successful in satisfactory yields.