Easy Routes towards Chiral Lithium Binaphthylamido Catalysts for the Asymmetric Hydroamination of Amino‐1,3‐dienes and Aminoalkenes

Deschamp, Julia; Collin, Jacqueline; Hannedouche, Jérôme; Schulz, Emmanuelle

doi:10.1002/ejoc.201001596

Cited by 39 publications

(9 citation statements)

References 103 publications

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“…Still, great progress is highlighted by advances with metallocene-based and axially chiral lanthanide catalysts, − alkali metal coordination complexes, and alkaline earth metal catalysts . Breakthroughs in zirconium-catalyzed alkene hydroamination include axially chiral bis(aryloxy), bis(amido), a highly enantioselective bis(amidate) − and bis(carboxyamide) complexes (or similar Ta-based systems) as catalysts.…”

Section: Introductionmentioning

confidence: 99%

Highly Enantioselective Zirconium-Catalyzed Cyclization of Aminoalkenes

et al. 2013

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Aminoalkenes are catalytically cyclized in the presence of cyclopentadienylbis(oxazolinyl)borato group 4 complexes {PhB(C5H4)(OxR)2}M(NMe2)2 (M = Ti, Zr, Hf; OxR = 4,4-dimethyl-2-oxazoline, 4S-isopropyl-5,5-dimethyl-2-oxazoline, 4S-tert-butyl-2-oxazoline) at room temperature and below, affording five-, six-, and seven-membered N-heterocyclic amines with enantiomeric excesses of >90% in many cases and up to 99%. Mechanistic investigations of this highly selective system employed synthetic tests, kinetics, and stereochemistry. Secondary aminopentene cyclizations require a primary amine (1-2 equiv vs catalyst). Aminoalkenes are unchanged in the presence of a zirconium monoamido complex {PhB(C5H4)(Ox4S-iPr,Me2)2}Zr(NMe2)Cl or a cyclopentadienylmono(oxazolinyl)borato zirconium diamide {Ph2B(C5H4)(Ox4S-iPr,Me2)}Zr(NMe2)2. Plots of initial rate versus [substrate] show a rate dependence that evolves from first-order at low concentration to zero-order at high concentration, and this is consistent with a reversible substrate-catalyst interaction preceding an irreversible step. Primary kinetic isotope effects from substrate conversion measurements (k′obs(H)/k′obs(D) = 3.3 ± 0.3) and from initial rate analysis (k2(H)/k2(D) = 2.3 ± 0.4) indicate that a N-H bond is broken in the turnover-limiting and irreversible step of the catalytic cycle. Asymmetric hydroamination/cyclization of N-deutero-aminoalkenes provides products with higher optical purities than obtained with N-proteo-aminoalkenes. Transition state theory, applied to the rate constant k2 that characterizes the irreversible step, provides activation parameters consistent with a highly organized transition state (ΔS⧧ = −43(7) cal·mol-1 K-1) and a remarkably low enthalpic barrier (ΔH⧧ = 6.7(2) kcal·mol-1). A six-centered, concerted transition state for C-N and C-H bond formation and N-H bond cleavage involving two amidoalkene ligands is proposed as most consistent with the current data. ABSTRACT: Aminoalkenes are catalytically cyclized in the presence of cyclopentadienylbis(oxazolinyl)borato group 4 complexes {PhB(C 5 H 4 )(Ox R ) 2 }M(NMe 2 ) 2 (M = Ti, Zr, Hf; Ox R = 4,4-dimethyl-2-oxazoline, 4S-isopropyl-5,5-dimethyl-2-oxazoline, 4S-tert-butyl-2-oxazoline) at room temperature and below, affording five-, six-, and seven-membered N-heterocyclic amines with enantiomeric excesses of >90% in many cases and up to 99%. Mechanistic investigations of this highly selective system employed synthetic tests, kinetics, and stereochemistry. Secondary aminopentene cyclizations require a primary amine (1−2 equiv vs catalyst). Aminoalkenes are unchanged in the presence of a zirconium monoamido complex {PhB(C 5 H 4 )(Ox 4S-iPr,Me 2 ) 2 }Zr(NMe 2 )Cl or a cyclopentadienylmono(oxazolinyl)borato zirconium diamide {Ph 2 B(C 5 H 4 )-(Ox 4S-iPr,Me 2 )}Zr(NMe 2 ) 2 . Plots of initial rate versus [substrate] show a rate dependence that evolves from first-order at low concentration to zero-order at high concentration, and this is consistent with a reversible substrate−catalyst interac...

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Section: Introductionmentioning

confidence: 99%

Highly Enantioselective Zirconium-Catalyzed Cyclization of Aminoalkenes

et al. 2013

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“…While there has been interest in enantioselective hydroamination of 1,3-dienes, 14 most studies have focused on intramolecular variants. 15 Prior to our study, Hartwig demonstrated the only example of an enantioselective, intermolecular hydroamination of 1,3-dienes; this study focused on cyclohexadiene. 3 In contrast, enantioselective hydroamination of unsymmetric dienes had yet to be achieved.…”

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confidence: 99%

Rhodium-Catalyzed Hydrofunctionalization: Enantioselective Coupling of Indolines and 1,3-Dienes

2017

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We communicate a strategy for the hydrofunctionalization of 1,3-dienes via Rh-hydride catalysis. Conjugated dienes are coupled to nucleophiles to demonstrate the feasibility of novel C-C, C-O, C-S, and C-N bond forming processes. In the presence of a chiral JoSPOphos ligand, hydroamination generates chiral allylic amines with high regio- and enantioselectivity. Tuning both the pK and steric properties of an acid-additive is critical for enantiocontrol.

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“…A few years ago, our group reported the first application of chiral diamidobinaphthyldilithium salts as easily available and efficient alkali‐metal‐based (pre)catalysts for the asymmetric cyclohydroamination of amino‐1,3‐dienes with the highest stereo‐ and enantioselectivities described to date (up to 93:7 dr and 71 % ee ) . The methodology was further extended to the enantioselective intramolecular hydroamination of primary and secondary amines tethered to alkenes at room temperature with ee values up to 58 % . These efficient lithium‐based catalysts were in situ prepared by a straightforward protocol resulting from the combination of N ‐substituted ( R )‐(+)‐1,1′‐binaphthyl‐2,2′‐diamines such as ( R )‐H 2 L 1–3 (Figure ) and LiCH 2 TMS in a 1:2.5 ratio.…”

Section: Methodsmentioning

confidence: 99%

Lithium‐Catalyzed anti‐Markovnikov Intermolecular Hydroamination Reactions of Vinylarenes and Simple Secondary Amines

et al. 2017

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Various β‐arylethylamine derivatives were straightforwardly obtained by the lithium‐catalyzed anti‐Markovnikov selective intermolecular hydroamination reaction of secondary aliphatic amines with vinylarenes. The use of only 1.5 mol % LiCH2TMS as a solid base in THF proved to be efficient to deliver the target products at room temperature with up to complete conversions. Both reaction partners were, moreover, used in equivalent amounts; thus, this protocol best respects the concepts of sustainable chemistry for the easy preparation of lead structures for pharmaceutically active compounds.

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Easy Routes towards Chiral Lithium Binaphthylamido Catalysts for the Asymmetric Hydroamination of Amino‐1,3‐dienes and Aminoalkenes

Cited by 39 publications

References 103 publications

Highly Enantioselective Zirconium-Catalyzed Cyclization of Aminoalkenes

Highly Enantioselective Zirconium-Catalyzed Cyclization of Aminoalkenes

Rhodium-Catalyzed Hydrofunctionalization: Enantioselective Coupling of Indolines and 1,3-Dienes

Lithium‐Catalyzed anti‐Markovnikov Intermolecular Hydroamination Reactions of Vinylarenes and Simple Secondary Amines

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