Asymmetric [3+2] Annulations to Construct 1,2‐Bispirooxindoles Incorporating a Dihydropyrrolidine Motif
Constructing chiral bispirooxindoles is difficult to achieve but highly attractive owing to their many potential applications in medicinal chemistry. Here we present an asymmetric [3+2] annulation reaction of Morita–Baylis–Hillman carbonates from isatins and isatin‐based N‐Boc‐ketimines under the ca...
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Veröffentlicht in: | Advanced synthesis & catalysis 2017-11, Vol.359 (21), p.3782-3791 |
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Format: | Artikel |
Sprache: | eng |
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Zusammenfassung: | Constructing chiral bispirooxindoles is difficult to achieve but highly attractive owing to their many potential applications in medicinal chemistry. Here we present an asymmetric [3+2] annulation reaction of Morita–Baylis–Hillman carbonates from isatins and isatin‐based N‐Boc‐ketimines under the catalysis of a newly designed multifunctional 4‐dimethylaminopyridine‐type substance. The reaction shows high γ‐regioselectivity, producing highly complex 1,2‐bispirooxindoles incorporating a dihydropyrrolidine motif in excellent yields with moderate to outstanding stereoselectivity (dr>19:1, up to >99% ee). This protocol has been expanded to utilize trifluoromethyl‐containing ketimines, delivering complicated architectures with fused and spirocyclic frameworks in modest enantioselectivity. |
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ISSN: | 1615-4150 1615-4169 |
DOI: | 10.1002/adsc.201700849 |