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2021-01-25 11:54:00

Scientists the Zelinsky Institute have discovered new aspects of the reactivity of donor-acceptor cyclopropanes

Donor−acceptor cyclopropanes are widely used in organic synthesis owing to their ability to react as synthetic equivalents of 1,3-zwitterions. Recently, reactions of donor−acceptor cyclopropanes where they exhibit other reactivity types have also been studied intensely.

As part of the ongoing research by the scientistss of the laboratory № 6 of the Zelinsky Institute on the reactivity of donor-acceptor cyclopropanes, a method was developed for the usage of a bicyclopropyl system activated by the incorporation of donor and acceptor groups as a synthetic equivalent of 1,6-zwitterions in the presence of Lewis acids. The use of the GaI3 + Bu4N+GaI4 system leads to the formation of products of the formal addition of HI to the bicyclopropyl system. Carrying out the reaction of the activated bicyclopropyl system with terminal alkynes in the presence of GaCl3 or GaBr3 as a Lewis acid makes it possible to obtain acyclic 7-chloro(bromo)-hepta-2,6-dienylmalonates. The reaction of the bicyclopropyl system with 4-phenyl-1,2,4-triazoline-3,5-dione (PTAD) catalyzed by Yb(OTf)3 is also accompanied by the opening of both cyclopropane rings, while one PTAD molecule leads to the formation of the annulated tetrahydropyridazine ring, and the second one is incorporated in the malonyl fragment.

 

 

Source:

Konstantin V. Potapov, Dmitry A. Denisov, Valeriia V. Glushkova, Roman A. Novikov, Yury V. Tomilov Donor−Acceptor Bicyclopropyls as 1,6-Zwitterionic Intermediates: Synthesis and Reactions with 4‑Phenyl-1,2,4-triazoline-3,5-dione and Terminal Acetylenes J. Org. Chem. 2020, 85, 23, 15562–15576. DOI: 10.1021/acs.joc.0c02293.

Important events:

The European Academy of Sciences (Academia Europaea) was founded in 1988. It unites about four thousand globally acknowledged experts in mathematics, medicine, natural sciences, humanities, law, economy, and social and political sciences from many countries of Europe. Among its members are also European scientists who live in other regions of the world. Currently, it includes seventy two Nobel laureates and it should be highlighted that many of them were elected to the Academy before winning the Prize.
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