Nowe zastosowania D-A cyklopropanów w syntezach heterocykli siarkowych oraz innych związków siarkoorganicznych

Abstract

The main goal of the research carried out as a part of the doctoral dissertation was the search for new reactions of known D-A cyclopropanes (Donor-Acceptor Cyclopropanes) in the syntheses of cyclic and acyclic organosulfur compounds by cycloaddition or addition reactions with such substrates as thioketenes, thioketones (tropothione) and enolizable azaheterocyclic thiones. In the first part of the research, it was demonstrated that, analogously to the previously studied ferrocenyl thioketones, (3+2)-cycloadditions of D-A of cyclopropanes with thioketenes carried out under mild conditions, in the presence of scandium triflate Sc(OTf)3 as a catalyst, led to 5-membered thiolanes (tetrahydrothiophenes) functionalized with a methylidene group in the C(2) position. It was found that (8+3)-cycloadditions of D-A cyclopropanes with tropothione proceeded in a completely stereoselective manner and led to previously unknown bicyclic thiopyran derivatives in high yields. In the second phase of the presented research, D-A reactions of cyclopropanes with enolizable and non-enolizable azaheterocyclic thions of different ring sizes were tested. It turned out that 1-substituted 5-mercaptotetrazoles reacted with D-A-cyclopropanes to give open-chain products formally formed via competitive insertions into S-H or N-H bonds of both tautomeric forms. The ambident reactivity leading to competatove formation of both S- and N-insertion producrs has been observed in a series of derivatives of 2-mercapto-1,3,4-thiadiazole.