Origins of the high stereoselectivity in the conjugate addition of lithium(α-methylbenzyl)benzylamide to t-butyl cinnamate

Costello, James F.; Davies, Stephen G.; Ichihara, Osamu

doi:10.1016/s0957-4166(00)86275-8

Cited by 118 publications

(86 citation statements)

References 16 publications

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“…The absolute configuration at C(3) within (3S,αS)-9 relative to the N-α-methylbenzyl stereocentre is assigned by analogy with previous authenticated models developed to explain the stereoselectivity observed during addition of lithium amide (S)-1 to α,β-unsaturated acceptors [10]. …”

Section: Resultsmentioning

confidence: 82%

A Convenient Asymmetric Synthesis of a β-amino Ester with Additional Functionalization as a Precursor for Peptide Nucleic Acid (PNA) Monomers

et al. 2006

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Abstract:We report the asymmetric synthesis of di-3-pentyl (3S,αS,7E)-3-N-benzyl-N-α-methylbenzylamino-dec-7-enedioate (9), which contains the correct functionalization to produce δ-amino acid derivatives to be used as monomers for Peptide Nucleic Acid (PNA) formation With this aim, thymine-pentanoic acid 15 and some of its ester derivatives were obtained, their reactivity was studied and the noteworthy ethyl ester 12 was quantitatively produced by transesterification of methyl ester 11, thus paving the way for the synthesis of the thymine-containing amino ester IV, which has been designed as a building block for a Nucleic-Acid analog with a chiral, flexible peptide backbone

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Section: Resultsmentioning

confidence: 82%

A Convenient Asymmetric Synthesis of a β-amino Ester with Additional Functionalization as a Precursor for Peptide Nucleic Acid (PNA) Monomers

et al. 2006

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“…The resulting amino ester enolates (i.e., 3 – ) typically aggregate to form homodimers 28 or mixed aggregates with lithium amides (not shown). The high diastereoselectivity is based on the large difference in the steric demand of the 1‐phenylethyl auxiliary in the transition states 25 vs. 26 , which effectively dictates the facial selectivity …”

Section: Discussionmentioning

confidence: 99%

N,2,3,4‐Tetrasubstituted Pyrrolidines through Tandem Lithium Amide Conjugate Addition/Radical Cyclization/Oxygenation Reactions

et al. 2016

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Enantioselective syntheses of densely functionalized pyrrolidines deriving their chirality from (R)‐1‐(phenyl)ethylamine are reported. Allylic amines and β‐substituted‐α,β‐unsaturated esters are used as the building blocks in this one‐pot reaction. Single electron transfer (SET) oxidation served to merge the reactivities of anionic enolate and radical intermediates. Ferrocenium hexafluorophosphate, which is easy to prepare, store and handle, was applied as SET oxidant and persistent free radical TEMPO served as the oxygenating agent introducing a protected hydroxy function, which proved to be beneficial for further derivatization. Exclusive 2,3‐trans and up to 6:1 3,4‐cis/trans diastereoselectivities were achieved in the targeted tetrasubstituted pyrrolidines.

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“…Davies showed that the preferred arrangement of conformation and stereofacial attack mode for chiral amides with cyclic and acyclic Michael acceptors corresponds to Figure 3. 21 In the case of a 3,3-dimethylcyclobutene-1-carboxylate substrate, such as 4, interference from the C3 methyl groups could destabilize this mode of attack. In the event, given the low stereochemical excesses observed, it is not possible to assert whether this mode persists at all, nor whether other modes become prevalent.…”

Section: Methodsmentioning

confidence: 99%

Evaluation of an aza-Michael approach for the synthesis of 3,3-dimethyl-2-aminocyclobutane-1-carboxylic acid

Charnay‐Pouget¹,

Mathur²,

Baltaze³

et al. 2011

Arkivoc

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The aza-Michael addition reaction of a dibenzylic amide anion with t-butyl 3,3-dimethylcyclobutene-1-carboxylate was investigated as a route to the title compound, a cyclic β-amino acid. In analogy with the known 5-and 6-membered ring homologues, the addition reaction proceeds smoothly, but with moderate diastereomeric and enantiomeric selectivities. The trans isomer of the title β-amino acid was obtained, for the first time, with a modest enantiomeric excess.

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Origins of the high stereoselectivity in the conjugate addition of lithium(α-methylbenzyl)benzylamide to t-butyl cinnamate

Cited by 118 publications

References 16 publications

A Convenient Asymmetric Synthesis of a β-amino Ester with Additional Functionalization as a Precursor for Peptide Nucleic Acid (PNA) Monomers

A Convenient Asymmetric Synthesis of a β-amino Ester with Additional Functionalization as a Precursor for Peptide Nucleic Acid (PNA) Monomers

N,2,3,4‐Tetrasubstituted Pyrrolidines through Tandem Lithium Amide Conjugate Addition/Radical Cyclization/Oxygenation Reactions

Evaluation of an aza-Michael approach for the synthesis of 3,3-dimethyl-2-aminocyclobutane-1-carboxylic acid

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