ИСТИНА

Direct C-H insertion (activation) methods represent one of the most promising directions in the development of organic synthesis. This strategy is especially acute for tetrapyrrole compounds. Ir-catalyzed direct C-H borylation and C-H silylation were used to modify relatively simple porphyrins. C-H insertion reactions involving carbenes are of particular interest. This work presents a new approach to the modification of tetrapyrrole compounds using the C-H insertion reaction via the carbene mechanism, in the presence of a base. N-tosylhydrazones of various tetrapyrrole compounds were used as a source of carbene. Cyclopropane derivatives 1' and 2' were formed in the reaction of the tosylhydrazones 1 and 2 with styrene. It was found, that along with the [2+1] cycloaddition reaction, the C-H insertion reaction took place at the methylene fragment of 1,4-dioxane used as a solvent. The procedure of interaction of tosylhydrazone 2 with the 1,4-dioxane was elaborated. In the reaction of meso-substituted tosylhydrazones 3-6 with styrene, the formation of the expected cyclopropane derivatives did not occur, while the products of the intramolecular C-H insertion reaction were formed yielding the corresponding exocyclic derivatives. It should be noted, that in the case of the cyclization of the porphyrin 3, a partial migration of the propionic acid fragment was observed leading to the formation of the rearrangement product 3'. Thus, the studied N-tosylhydrazone derived carbene mediated reactions open up the new possibilities of the tetrapyrrole synthetic chemistry. Acknowledgments: The reported study was funded by RFBR, project number 19-33-90234