Exploring Cyclization Strategies to Access Stemona Alkaloids: Subtle Effects Influencing Reactivity in Intramolecular Michael Additions
| Autor: | Wesley J. Olivier, Jason A. Smith, Alireza Ariafard, Alex C. Bissember, Nigel T. Lucas, Rasool Babaahmadi |
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| Rok vydání: | 2021 |
| Předmět: |
Stemona
biology 010405 organic chemistry Chemistry Stereochemistry Organic Chemistry Substituent 010402 general chemistry biology.organism_classification 01 natural sciences Biochemistry Transition state 0104 chemical sciences chemistry.chemical_compound Intramolecular force Electronic effect Reactivity (chemistry) Physical and Theoretical Chemistry Pyrrole |
| Zdroj: | Organic Letters. 23:8494-8498 |
| ISSN: | 1523-7052 1523-7060 |
| DOI: | 10.1021/acs.orglett.1c03205 |
| Popis: | This report investigates the fundamental basis for rather surprising patterns of reactivity in Bronsted acid-mediated cyclizations of pyrrole substrates bearing pendant Michael acceptors that were identified during syntheses of Stemona alkaloids. Integrated experimental and theoretical studies reveal the profound influence that substituent effects have on the viability of these transformations. Additionally, we identify that electronic effects, in addition to barrier-lowering secondary orbital interactions within transition states, account for the exclusive preference for 7-endo-trig cyclizations over 6-exo-trig cyclizations. |
| Databáze: | OpenAIRE |
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