Copper Cyanide-Catalyzed Palladium Coupling of <i>N</i>-<i>tert</i>-Butoxycarbonyl-Protected α-Lithio Amines with Aryl Iodides or Vinyl Iodides

and, R. Karl Dieter; Li, Shengjian

doi:10.1021/jo970985b

Cited by 66 publications

(30 citation statements)

References 60 publications

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“…Veliparib, 6 Pradaxa, 7 and Benthiavalicarb 8 ). While important strategies for amine α-arylation have been reported by Dieter, 9 Campos, 10 Nakamura, 11 and others, 12 a generic yet mild α-arylation protocol remains largely elusive.…”

Section: Introductionmentioning

confidence: 99%

Amine α-heteroarylation via photoredox catalysis: a homolytic aromatic substitution pathway

2014

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The direct α-heteroarylation of tertiary amines has been accomplished via photoredox catalysis to generate valuable benzylic amine pharmacophores. A variety of five-and six-membered chloroheteroarenes are shown to function as viable coupling partners for the α-arylation of a diverse range of cyclic and acyclic amines. Evidence is provided for a homolytic aromatic substitution mechanism, in which a catalyticallygenerated α-amino radical undergoes direct addition to an electrophilic chloroarene.

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Section: Introductionmentioning

confidence: 99%

Amine α-heteroarylation via photoredox catalysis: a homolytic aromatic substitution pathway

2014

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“…Previously, Dieter demonstrated that transmetalation of N -Boc-2-lithiopyrrolidine to its organocopper counterpart provides a convenient way to synthesize vinylated pyrrolidines 4,5. Using an asymmetric deprotonation methodology with the chiral base s -BuLi/(–)-sparteine6,7 to generate an enantioenriched organolithium, Dieter achieved enantioselective vinylations with er’s up to 93:7.…”

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confidence: 99%

Application of Catalytic Dynamic Resolution of N-Boc-2-lithiopiperidine to the Asymmetric Synthesis of 2-Aryl and 2-Vinyl Piperidines

Beng

Gawley

2010

Org. Lett.

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The highly enantioselective synthesis of 2-aryl-and 2-vinyl-piperidines has been accomplished through a catalytic dynamic resolution (CDR) of N-Boc-2-lithiopiperidine. The method has been applied to the synthesis of both enantiomers of the tobacco alkaloid anabasine.Optically active 2-aryl-and 2-vinyl-piperidines are found in a variety of natural products and some have useful pharmacological properties.1 -3 Previously, Dieter demonstrated that transmetalation of N-Boc-2-lithiopyrrolidine to its organocopper counterpart provides a convenient way to synthesize vinylated pyrrolidines.4 , 5 Using an asymmetric deprotonation methodology with the chiral base s-BuLi/(-)-sparteine6 , 7 to generate an enantioenriched organolithium, Dieter achieved enantioselective vinylations with er's up to 93:7. Later, Campos used the asymmetric deprotonation methodology and transmetalation to an organozinc species, followed by a palladium-mediated Negishi coupling with aryl bromides, to prepare N-Boc-2-arylpyrrolidines in good yields and ≥96:4 er's (Scheme 1).8 -11The remarkable chemical and configurational stability of the intermediate organozinc compound, even at 60 °C, and the high degree of tolerance for both electron rich and electron deficient aryl halides make this transformation very attractive.Previous attempts to synthesize enantioenriched 2-aryl-piperidines via Negishi coupling conditions have been less successful. O'Brien recently reported an asymmetric deprotonation of N-Boc-piperidine using s-BuLi and O'Brien's diamine12 (Figure 1), followed by trapping with 4-bromoveratrole, affording the arylated product in 33% yield and 82:18 er (S:R).11 Although the Coldham group successfully synthesized racemic members of this family via Negishi coupling,13 attempts to effect enantioselectivity by dynamic thermodynamic resolution (DTR) using stoichiometric amount of chiral ligand led to no arylation products.14 They reported two examples of enantioenriched 2-aryl-piperidines (er bgawley@uark.edu. Supporting Information Available Full experimental details and spectroscopic data. This information is available free of charge via the internet at http://pubs.acs.org. We recently reported the highly enantioselective synthesis of 2-substituted piperidines by catalytic dynamic resolution (CDR) of N-Boc-2-lithiopiperidine 1 using diastereomeric ligands (S,S)-2 and (S,R)-2 ( Figure 1).15 In our report, we utilized copper-mediated coupling to synthesize enantioenriched 2-allyl and 2-benzyl-piperidines (Scheme 2) via an organozinc reagent formed by transmetalation of the resolved N-Boc-2-lithiopiperidine. NIH Public AccessWe know (Scheme 2) that during transmetalation of lithium to zinc, then to copper, configurational stability is maintained. Based on Campos' results (Scheme 1), we hoped that during transmetalation from zinc to palladium, configurational integrity would be retained.Considering that we are able to resolve N-Boc-2-lithiopiperidine catalytically, we investigated a CDR in the Negishi arylations and vinylations. We herein e...

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“…Products were characterized by the comparison of their physical and spectral data with authentic samples [10,16,17,20,[25][26][27][28][29][30][31]. …”

Section: Methodsmentioning

confidence: 99%

Succinimide sulfonic acid (SuSA): an efficient and recyclable catalyst for the chemoselective N-Boc protection of amines

Shirini

Khaligh

2011

Monatsh Chem

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Copper Cyanide-Catalyzed Palladium Coupling of N-tert-Butoxycarbonyl-Protected α-Lithio Amines with Aryl Iodides or Vinyl Iodides

Cited by 66 publications

References 60 publications

Amine α-heteroarylation via photoredox catalysis: a homolytic aromatic substitution pathway

Amine α-heteroarylation via photoredox catalysis: a homolytic aromatic substitution pathway

Application of Catalytic Dynamic Resolution of N-Boc-2-lithiopiperidine to the Asymmetric Synthesis of 2-Aryl and 2-Vinyl Piperidines

Succinimide sulfonic acid (SuSA): an efficient and recyclable catalyst for the chemoselective N-Boc protection of amines

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