Hryschuk O. [2+1] and [2+2] cycloadditions involving alkenyl boronic derivatives.

The dissertation focuses on the synthesis of boron derivatives of cyclopropane and cyclobutane based [2 + 1] and [2 + 2] cycloaddition reactions, and the prospects for the use of the obtained building blocks in organic synthesis, with cross-coupling reactions as an example. In the scope of the thesis research, a method for the synthesis of functionalized 1,2-disubstituted cyclopropyltrifluoroborates via the reaction of vinyl trifluoroborates with diazoacetates and similar diazoalkanes catalyzed by Pd(OAc)2 was developed. The obtained cyclopropyltrifluoroborates were shown to be convenient starting compounds in the Curtius reaction, as well as in the Suzuki and Chen-Lam cross-coupling reactions for the preparation of (het)arylcyclopropanes. Using acyclic, exocyclic, and endocyclic alkenyltrifluoroborates, difluorocyclopropanation was performed with the (CH3)3SiCF3–NaI system, which allowed obtaining functionalized monocyclic, spirocyclic, and fused gem-difluorocyclopropanes in good yields.