Enantioselective Dehydrogenative Heck Arylations of Trisubstituted Alkenes with Indoles to Construct Quaternary Stereocenters

Journal of the American Chemical Society, Journal Year: 2015, Volume and Issue: 137(50), P. 15668 - 15671

Published: Dec. 1, 2015

An enantioselective, intermolecular dehydrogenative Heck arylation of trisubstituted alkenes to construct remote quaternary stereocenters has been developed. Using a new chiral pyridine oxazoline ligand, good high enantioselectivity is achieved for various combinations indole derivatives and alkenes. However, some substrates led lower enantioselectivity, which provided the impetus use structure correlations design better performing ligand.

Language: Английский

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Catalytic Asymmetric Umpolung Allylation of Imines

Journal of the American Chemical Society, Journal Year: 2016, Volume and Issue: 138(40), P. 13103 - 13106

Published: Sept. 19, 2016

Here we report an iridium-catalyzed asymmetric umpolung allylation of imines as a general approach to prepare 1,4-disubstituted homoallylic amines, fundamental class compounds that are hitherto not straightforward obtain. This transformation proceeds by cascade involving intermolecular regioselective 2-azaallyl anions and following 2-aza-Cope rearrangement, utilizes easily available reagents catalysts, tolerates substantial scope substrates, readily leads various enantioenriched, primary amines.

Language: Английский

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Study of Intermediates in Iridium–(Phosphoramidite,Olefin)-Catalyzed Enantioselective Allylic Substitution

Journal of the American Chemical Society, Journal Year: 2017, Volume and Issue: 139(10), P. 3603 - 3606

Published: March 7, 2017

Experimental mechanistic studies of iridium-catalyzed, enantioselective allylic substitution enabled by (phosphoramidite,olefin) ligands are reported. (η2-Allylic alcohol)iridium(I) and (η3-allyl)iridium(III) complexes were synthesized characterized NMR spectroscopy as well X-ray crystallography. The substrate catalytically kinetically competent to be intermediates in substitutions branched, racemic alcohols with various nucleophiles. In addition, we have identified an off-cycle pathway involving reversible binding molecular oxygen iridium, which contributes the air tolerance catalyst system.

Language: Английский

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Enantioselective Synthesis of Indole-Annulated Medium-Sized Rings

Journal of the American Chemical Society, Journal Year: 2016, Volume and Issue: 138(18), P. 5793 - 5796

Published: April 19, 2016

Asymmetric synthesis of indole-annulated medium-sized-ring compounds is developed through an iridium-catalyzed allylic dearomatization/retro-Mannich/hydrolysis cascade reaction. The reaction features mild conditions and a broad substrate scope. Under the optimal conditions, various seven-, eight-, or nine-membered-ring can be afforded in good to excellent yields enantioselectivity. proposed mechanism supported by capturing dearomatized intermediate situ reduction.

Language: Английский

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Uniting C1-Ammonium Enolates and Transition Metal Electrophiles via Cooperative Catalysis: The Direct Asymmetric α-Allylation of Aryl Acetic Acid Esters

Journal of the American Chemical Society, Journal Year: 2016, Volume and Issue: 138(16), P. 5214 - 5217

Published: March 30, 2016

The direct, catalytic, asymmetric α-functionalization of acyclic esters constitutes a significant challenge in the area catalysis, particularly where configurational integrity products is problematic. Through unprecedented merger two independent, yet complementary, catalysis events it has been possible to facilitate direct α-allylation readily available aryl acetic acid esters. Since enantioselection determined by nucleophile, this conceptual approach cooperative potentially general solution catalytic

Language: Английский

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Chemo‐, Diastereo‐, and Enantioselective Iridium‐Catalyzed Allylic Intramolecular Dearomatization Reaction of Naphthol Derivatives

Angewandte Chemie International Edition, Journal Year: 2016, Volume and Issue: 55(10), P. 3496 - 3499

Published: Feb. 5, 2016

Abstract An iridium‐catalyzed intramolecular asymmetric allylic dearomatization reaction of naphthol derivatives is described. Challenges confronted in this include chemoselectivity between carbon and oxygen atoms as nucleophilic centers, diastereoselectivity when contiguous chiral centers are generated, enantioselective control for constructing an all‐carbon quaternary stereocenter. In the presence iridium catalyst generated from [{Ir(dbcot)Cl} 2 ] (dbcot=dibenzocyclooctatetraene) a new THQphos (tetrahydroquinolinedinaphthophosphoramidite) ligand, various spironaphthalenones were obtained with up to greater than 95:5 C/O selectivity, d.r., 99 % ee , thus providing general method naphthols.

Language: Английский

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Iridium-Catalyzed Intramolecular Asymmetric Allylic Dearomatization Reaction of Pyridines, Pyrazines, Quinolines, and Isoquinolines

Journal of the American Chemical Society, Journal Year: 2015, Volume and Issue: 137(50), P. 15899 - 15906

Published: Nov. 25, 2015

The first Ir-catalyzed intramolecular asymmetric allylic dearomatization reaction of pyridines, pyrazines, quinolines, and isoquinolines has been developed. Enabled by in situ formed chiral Ir-catalyst, the dearomatized products were isolated high levels yield (up to 99% yield) enantioselectivity ee). It is worth noting that Me-THQphos ligand much more efficient than other tested ligands for pyrazines certain quinolines. Mechanistic studies carried out, results suggest feasibility an alternative process which features formation a quinolinium as key intermediate. mechanistic findings render this yet unknown type chemistry Reissert-type reactions. In addition, utility method was showcased large-scale formal synthesis (+)-gephyrotoxin.

Language: Английский

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Enantioselective Terminal Addition to Allenes by Dual Chiral Primary Amine/Palladium Catalysis

Journal of the American Chemical Society, Journal Year: 2017, Volume and Issue: 139(10), P. 3631 - 3634

Published: Feb. 26, 2017

We herein describe a synergistic chiral primary amine/achiral palladium catalyzed enantioselective terminal addition to allenes with α-branched β-ketocarbonyls and aldehydes. The reactions afford allylic adducts bearing acyclic all-carbon quaternary centers high regio- enantioselectivity. A wide range of including those aliphatic or 1,1′-disubstituted could be employed, thus expanding the scope typical asymmetric alkylation reactions.

Language: Английский

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Ir-Catalyzed Reverse Prenylation of 3-Substituted Indoles: Total Synthesis of (+)-Aszonalenin and (−)-Brevicompanine B

Journal of the American Chemical Society, Journal Year: 2014, Volume and Issue: 136(48), P. 16756 - 16759

Published: Nov. 3, 2014

The selective reverse prenylation of 3-substituted-1H-indoles at C3 is described. iridium-catalyzed reaction proceeds with high branched to linear selectivity (>20:1) for a variety indoles. In addition, diastereoselective tryptophan methyl ester disclosed, and its synthetic utility demonstrated in the synthesis (+)-aszonalenin (−)-brevicompanine B.

Language: Английский

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Ir-catalyzed intermolecular asymmetric allylic dearomatization reaction of indoles

Chemical Science, Journal Year: 2013, Volume and Issue: 5(3), P. 1059 - 1059

Published: Nov. 19, 2013

An Ir-catalyzed intermolecular asymmetric dearomatization reaction of substituted indoles with allylic alcohols has been realized to afford the corresponding indoline derivatives in 71–97% yield up 98% ee presence Lewis acid Fe(OTf)2. This methodology features enantioselective construction all-carbon quaternary stereogenic centers prochiral nucleophiles and its utility demonstrated total synthesis (−)-debromoflustramine B.

Language: Английский

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