Racemic hemiacetals as oxygen-centered pronucleophiles triggering cascade 1,4-addition/ Michael reaction through dynamic kinetic resolution under iminium catalysis. Development and mechanistic insights
2-Hydroxydihydropyran-5-ones behave as excellent polyfunctional reagents able to react with enals through oxa-Michael/Michael process cascade under the combination of iminium and enamine catalysis. These racemic hemiacetalic compounds are used as unconventional O-pronucleophiles in the initial oxa-M...
| Autores: | , , , , , , , |
|---|---|
| Tipo de recurso: | artículo |
| Fecha de publicación: | 2017 |
| País: | España |
| Institución: | Universidad del País Vasco |
| Repositorio: | Addi. Archivo Digital para la Docencia y la Investigación |
| OAI Identifier: | oai:addi.ehu.eus:10810/27571 |
| Acceso en línea: | http://hdl.handle.net/10810/27571 |
| Access Level: | acceso abierto |
| Palabra clave: | oxa-michael reaction enantioselective total-synthesis c-heteroatom bonds alpha,beta-unsaturated aldehydes asymmetric-synthesis conjugate addition domino reactions diastereoselective synthesis carbonyl-compounds organocatalytic epoxidation |
| Sumario: | 2-Hydroxydihydropyran-5-ones behave as excellent polyfunctional reagents able to react with enals through oxa-Michael/Michael process cascade under the combination of iminium and enamine catalysis. These racemic hemiacetalic compounds are used as unconventional O-pronucleophiles in the initial oxa-Michael reaction, also leading to the formation of a single stereoisomer under a dynamic kinetic resolution (DKR) process. Importantly, by using beta-aryl or beta-alkyl substituted alpha,beta-unsaturated substrates as initial Michael acceptors either kinetically or thermodynamically controlled diastereoisomers were formed with high stereoselection through the careful selection of the reaction conditions. Finally, a complete experimental and computational study confirmed the initially proposed DKR process during the catalytic oxa-Michael/Michael cascade reaction and also explained the kinetic/thermodynamic pathway operating in each case. |
|---|