Synergistic formal ring contraction for the enantioselective synthesis of spiropyrazolones
| Autor: | Martin Kamlar, Lucie Jašíková, Bedřich Formánek, Marta Meazza, Ramon Rios, Jan Veselý, Jana Roithová, Andrea Mazzanti |
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| Přispěvatelé: | Meazza, Marta, Kamlar, Martin, Jašíková, Lucie, Formánek, Bedřich, Mazzanti, Andrea, Roithová, Jana, Veselý, Jan, Rios, Ramon |
| Rok vydání: | 2018 |
| Předmět: |
010405 organic chemistry
Chemistry Chemistry (all) Enantioselective synthesis chemistry.chemical_element Infrared spectroscopy Protonation General Chemistry 010402 general chemistry 01 natural sciences Combinatorial chemistry Cycloaddition 0104 chemical sciences Catalysis chemistry.chemical_compound Amine gas treating Organic synthesis Palladium |
| Zdroj: | Chemical Science |
| ISSN: | 2041-6539 2041-6520 |
| DOI: | 10.1039/c8sc00913a |
| Popis: | We report the first ring contraction/formal [6 + 2] cycloaddition using synergistic Pd(0)/secondary amine catalysis, obtaining [5,5]-spiropyrazolone derivatives in excellent yields and stereoselectivities. We detected the key palladium activated intermediate in its protonated form by mass spectrometry and characterized its structure by infrared spectroscopy and DFT calculations, allowing us to propose a conceivable mechanistic pathway for this reaction. The rapid generation of molecular complexity from simple reactants is a key challenge in organic synthesis. Spiro compounds, underrepresented 3D motifs in chemical libraries, represent a challenge due to the creation of spiro quaternary carbon and the need to control the 3D shape in one step. Herein, we report the first ring contraction/formal [6 + 2] cycloaddition using synergistic Pd(0)/secondary amine catalysis, obtaining [5,5]-spiropyrazolone derivatives in excellent yields and stereoselectivities. We demonstrate that this reaction has a broad scope of early and late stage derivatization that will benefit the creation of highly valuable chemical libraries using spiropyrazolone motifs. We detected the key palladium activated intermediate in its protonated form by mass spectrometry and characterized its structure by infrared spectroscopy and DFT calculations, allowing us to propose a conceivable mechanistic pathway for this reaction. |
| Databáze: | OpenAIRE |
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