Palladium-Catalyzed Asymmetric Intramolecular Dearomative Heck Annulation of Aryl Halides to Furnish Indolines
An unprecedented Pd-catalyzed asymmetric intramolecular cascade cyclization of aryl halides with readily available arylboronic acids proceeds through a Heck-type dearomative cyclization terminated with arylation in the presence of Pd2(dba)3 (10 mol %), Cu2O (5 mol %), and Cs2CO3 (2.0 equiv) in 1,2-d...
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Veröffentlicht in: | Journal of organic chemistry 2021-11, Vol.86 (21), p.14640-14651 |
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Hauptverfasser: | , , , , , |
Format: | Artikel |
Sprache: | eng |
Online-Zugang: | Volltext |
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Zusammenfassung: | An unprecedented Pd-catalyzed asymmetric intramolecular cascade cyclization of aryl halides with readily available arylboronic acids proceeds through a Heck-type dearomative cyclization terminated with arylation in the presence of Pd2(dba)3 (10 mol %), Cu2O (5 mol %), and Cs2CO3 (2.0 equiv) in 1,2-dichloroethane (1.0 mL) at 100 °C for 15 h in air using BINOL-based phosphoramidite as the chiral ligand. This dearomative Heck protocol, which tolerates a broad variety of functional groups, is amenable to the generation of optically active indoline derivatives bearing all-carbon quaternary stereogenic centers in one step in moderate to excellent yields, with excellent diastereoselectivities (>20:1) and enantioselectivities (up to >99% ee). It is worth mentioning that no decrease in the enantiopurity of the indoline derivatives was observed during the synthetic transformations of the products. |
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ISSN: | 0022-3263 1520-6904 |
DOI: | 10.1021/acs.joc.1c01478 |