Abstract
The studies on the reaction of masked o-benzoquinones (MOBs) 2 with enamines, pyrroles and indoles are described. This thesis consists of three parts: the first part is concerned with the cycloaddition reactions of MOBs with enamines. The second part deals with the cycloaddition reaction of MOBs with pyrroles. The last part describes the reactions of MOBs with indoles. In the first part, bicyclo[2.2.2]octenone derivatives 42-48 were obtained in the cycloaddition reactions of MOBs 2 and enamines. The results showed that these reactions are highly regioselective, but not highly stereoselective. The cycloadducts obtained are ortho and the orientation of amino/imino group in the major product is syn to the octenone carbonyl function. The calculations performed by RHF/STO-3G and RHF/3-21G methods suggest that enamines may play the role of dienophiles in these reactions. The investigations on the cycloaddition reactions of MOBs 2 and pyrroles are presented in the second part. The cycloadducts 72-80 were obtained as single stereoisomers in the reactions of MOBs 2 with pyrrole and its derivatives. The pyrroles having no substituents or electron- releasing substituents on the nitrogen atom furnished Michael adducts 72 and 73, whereas the electron-withdrawing group on the nitrogen of pyrroles afforded the Diels-Alder adducts 74-80. The analyses of the calculations by RHF/STO-3G and RHF/3-21G methods suggest that pyrroles may play the role of Michael donors in these Diels-Alder reactions. It is important to note that in these processes two aromatic compounds are employed to generate highly complex and potentially useful multifunctional compounds 72-80 with high regio- and stereoselecty. The last part describes the reactions of MOBs 2 with indoles. It is evidenced that 3-substituted indoles prefer to act as dienophiles, and 2-substituted indoles prefer to act as Michael donors. On the other hand, indoles that lack substituents in the both 2- and 3-positions exhibit dual behavior depending on the conditions employed. The calculations carried out by RHF/STO-3G method support the obtained results. Two planar compounds are utilized to produce highly complex and potentially useful multifunctional tricyclic aliphatic compounds containing dihydroindole moiety in a simple one-pot process.