Catalyst-free formal [3 + 2] cycloaddition of stabilized N,N-cyclic azomethine imines to 3-nitrobenzofurans and 3-nitro-4H-chromenes: access to heteroannulated pyrazolo[1,2-a]pyrazoles

Autor:	Alina A. Artemenko, Vadim A. Shiryaev, Kirill S. Korzhenko, Oleg P. Demidov, Daria A. Rashchepkina, Dmitry V. Osipov, Vitaly A. Osyanin
Rok vydání:	2021
Předmět:	Computational chemistry Chemistry Atom economy Organic Chemistry Nitro Atomic charge Physical and Theoretical Chemistry Biochemistry Cycloaddition Catalysis
Zdroj:	Organic & Biomolecular Chemistry. 19:10156-10168
ISSN:	1477-0539 1477-0520
DOI:	10.1039/d1ob01377g
Popis:	We have studied the [3 + 2]-cycloaddition of various N,N-cyclic azomethine imines to 3-nitrobenzofurans. This process is a rare example of their dearomatization. We have also extended this process to the related 3-nitro-4H-chromenes as dipolarophiles. Both reactions provide access to benzofuro- and chromeno-condensed pyrazolo[1,2-a]pyrazoles with 100% atom economy in a diastereoselective manner under mild eco-friendly conditions. Finally, on the basis of DFT calculations, the mechanistic insights into the mentioned [3 + 2]-cycloadditions and explanations of the experimentally determined limitations of the method are given. Hirshfeld atomic charge values of push–pull heterocycles were suggested as a criterion for a priori assessment of the possibility of their dipolar cycloaddition with N,N-cyclic azomethine imines.
Databáze:	OpenAIRE
Externí odkaz:	https://explore.openaire.eu/search/publication?articleId=doi_________::bb7c141beb08df477b7d4f4aee38cd82 https://doi.org/10.1039/d1ob01377g Zobrazit plný text záznamu