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Enantioselective oxa‐Diels–Alder Sequences of Dendralenes

Diene‐transmissive hetero‐Diels–Alder sequences involving carbonyl dienophiles are reported for the first time. High enantioselectivities are achieved in the reaction of phenylglyoxal with a broad range of dendralene structures, through the optimization of a Pd(2+) catalyst system. The initial catal...

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Detalles Bibliográficos
Autores principales: Fan, Yi‐Min, Yu, Li‐Juan, Gardiner, Michael G., Coote, Michelle L., Sherburn, Michael S.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: John Wiley and Sons Inc. 2022
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9804868/
https://www.ncbi.nlm.nih.gov/pubmed/35900232
http://dx.doi.org/10.1002/anie.202204872
Descripción
Sumario:Diene‐transmissive hetero‐Diels–Alder sequences involving carbonyl dienophiles are reported for the first time. High enantioselectivities are achieved in the reaction of phenylglyoxal with a broad range of dendralene structures, through the optimization of a Pd(2+) catalyst system. The initial catalyst‐controlled enantioselective oxa‐Diels–Alder (ODA) cycloaddition to a [3]dendralene generates a dihydropyran carrying a semicyclic diene. This participates in a subsequent catalyst or substrate‐controlled Diels–Alder reaction to generate sp(3)‐rich fused polycyclic systems containing both heterocycles and carbocycles. Computational investigations reveal a concerted asynchronous mechanism. π‐Complexation of a diene C=C bond to Pd(2+) occurs in both the pre‐transition state (TS) complex and in cycloaddition TSs, controlling stereoselectivity. A formal enantioselective [4+2]cycloaddition of a CO(2) dienophile is demonstrated.