LrgpV1, Main, Curation, bibRecord, 000D87

Transition States and Origins of 1,4‐Asymmetric Induction in Alkylations of 2,2,6‐Trialkylpiperidine Enamines

Identifieur interne : 000D87 ( Main/Curation ); précédent : 000D86; suivant : 000D88

Transition States and Origins of 1,4‐Asymmetric Induction in Alkylations of 2,2,6‐Trialkylpiperidine Enamines

Auteurs : Joann Um ; Naeem Kaka ; David Hodgson [Royaume-Uni] ; K. Houk [États-Unis]

Source :

Chemistry – A European Journal [ 0947-6539 ] ; 2010-06-01.

RBID : ISTEX:035F03995891F79B507BD6081B3B87643B691835

English descriptors

KwdEn :
- Aldehyde, Alkene, Alkylation, Alkylations, Allyl, Allyl bromide, Angew, Asymmetric induction, Axial, Axial methyl, Axial methyl group, Bromide, Chem, Conformation, Conformer, Enamine, Enantiomeric ratios, Equatorial, Equatorial position, Ethyl iodide, Gmbh, Good agreement, Hodgson, Intermolecular nucleophilic substitution, Isopropyl, Isopropyl enamine, Isopropyl group, Kgaa, Lone interaction, Lone pair, Methyl, Methyl enamine, Model enamines, Olefinic protons, Phys, Piperidine, Piperidine ring, Preferential attack, Relative enthalpies, Transition state, Transition states, Transition structures, Unfavorable interaction, Verlag, Verlag gmbh, Weinheim, Weinheim chem.
Teeft :
- Aldehyde, Alkene, Alkylation, Alkylations, Allyl, Allyl bromide, Angew, Asymmetric induction, Axial, Axial methyl, Axial methyl group, Bromide, Chem, Conformation, Conformer, Enamine, Enantiomeric ratios, Equatorial, Equatorial position, Ethyl iodide, Gmbh, Good agreement, Hodgson, Intermolecular nucleophilic substitution, Isopropyl, Isopropyl enamine, Isopropyl group, Kgaa, Lone interaction, Lone pair, Methyl, Methyl enamine, Model enamines, Olefinic protons, Phys, Piperidine, Piperidine ring, Preferential attack, Relative enthalpies, Transition state, Transition states, Transition structures, Unfavorable interaction, Verlag, Verlag gmbh, Weinheim, Weinheim chem.

Abstract

The asymmetric C‐alkylation of chiral enamines derived from terminal epoxides and lithium 2,2,6‐trialkylpiperidides has previously been shown to provide α‐alkylated aldehydes by intermolecular nucleophilic substitution in good levels of asymmetric induction. We now report a computational study of the origins of asymmetric induction in these reactions. Computational modeling with density functional theory (B3LYP/6‐31G(d)) agrees closely with the experimental observations. This stereoselectivity is attributed to a preferential conformation of the enamine and the piperidine ring that places the C‐6 alkyl substituent in an axial position due to A1, 3 strain. Preferential attack occurs away from the axial group, for steric reasons. The effects of changing the C‐6 substituent from methyl to isopropyl were studied, and twist transition states were found to contribute significantly in the latter alkylations.

Url:

DOI: 10.1002/chem.201000046

Links toward previous steps (curation, corpus...)

to stream Istex, to step Corpus: Pour aller vers cette notice dans l'étape Curation :001724
to stream Istex, to step Curation: Pour aller vers cette notice dans l'étape Curation :001724
to stream Istex, to step Checkpoint: Pour aller vers cette notice dans l'étape Curation :000111
to stream Pmc, to step Corpus: Pour aller vers cette notice dans l'étape Curation :000113
to stream Pmc, to step Curation: Pour aller vers cette notice dans l'étape Curation :000113
to stream Pmc, to step Checkpoint: Pour aller vers cette notice dans l'étape Curation :000089
to stream Ncbi, to step Merge: Pour aller vers cette notice dans l'étape Curation :000172
to stream Ncbi, to step Curation: Pour aller vers cette notice dans l'étape Curation :000172
to stream Ncbi, to step Checkpoint: Pour aller vers cette notice dans l'étape Curation :000172
to stream Main, to step Merge: Pour aller vers cette notice dans l'étape Curation :000F62

Links to Exploration step

ISTEX:035F03995891F79B507BD6081B3B87643B691835

Curation

No country items

Joann Um

<affiliation><wicri:noCountry code="subField">(+1) 310‐206‐1843</wicri:noCountry>
</affiliation>

Naeem Kaka

<affiliation><wicri:noCountry code="subField">(+44) 1865‐285002</wicri:noCountry>
</affiliation>

Le document en format XML

<record><TEI wicri:istexFullTextTei="biblStruct"><teiHeader><fileDesc><titleStmt><title xml:lang="en">Transition States and Origins of 1,4‐Asymmetric Induction in Alkylations of 2,2,6‐Trialkylpiperidine Enamines</title>
<author><name sortKey="Um, Joann" sort="Um, Joann" uniqKey="Um J" first="Joann" last="Um">Joann Um</name>
</author>
<author><name sortKey="Kaka, Naeem" sort="Kaka, Naeem" uniqKey="Kaka N" first="Naeem" last="Kaka">Naeem Kaka</name>
</author>
<author><name sortKey="Hodgson, David" sort="Hodgson, David" uniqKey="Hodgson D" first="David" last="Hodgson">David Hodgson</name>
</author>
<author><name sortKey="Houk, K" sort="Houk, K" uniqKey="Houk K" first="K." last="Houk">K. Houk</name>
</author>
</titleStmt>
<publicationStmt><idno type="wicri:source">ISTEX</idno>
<idno type="RBID">ISTEX:035F03995891F79B507BD6081B3B87643B691835</idno>
<date when="2010" year="2010">2010</date>
<idno type="doi">10.1002/chem.201000046</idno>
<idno type="url">https://api.istex.fr/document/035F03995891F79B507BD6081B3B87643B691835/fulltext/pdf</idno>
<idno type="wicri:Area/Istex/Corpus">001724</idno>
<idno type="wicri:explorRef" wicri:stream="Istex" wicri:step="Corpus" wicri:corpus="ISTEX">001724</idno>
<idno type="wicri:Area/Istex/Curation">001724</idno>
<idno type="wicri:Area/Istex/Checkpoint">000111</idno>
<idno type="wicri:explorRef" wicri:stream="Istex" wicri:step="Checkpoint">000111</idno>
<idno type="wicri:doubleKey">0947-6539:2010:Um J:transition:states:and</idno>
<idno type="wicri:source">PMC</idno>
<idno type="url">http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3049728</idno>
<idno type="RBID">PMC:3049728</idno>
<idno type="wicri:Area/Pmc/Corpus">000113</idno>
<idno type="wicri:explorRef" wicri:stream="Pmc" wicri:step="Corpus" wicri:corpus="PMC">000113</idno>
<idno type="wicri:Area/Pmc/Curation">000113</idno>
<idno type="wicri:explorRef" wicri:stream="Pmc" wicri:step="Curation">000113</idno>
<idno type="wicri:Area/Pmc/Checkpoint">000089</idno>
<idno type="wicri:explorRef" wicri:stream="Pmc" wicri:step="Checkpoint">000089</idno>
<idno type="wicri:Area/Ncbi/Merge">000172</idno>
<idno type="wicri:Area/Ncbi/Curation">000172</idno>
<idno type="wicri:Area/Ncbi/Checkpoint">000172</idno>
<idno type="wicri:doubleKey">0947-6539:2010:Um J:transition:states:and</idno>
<idno type="wicri:Area/Main/Merge">000F62</idno>
<idno type="wicri:Area/Main/Curation">000D87</idno>
</publicationStmt>
<sourceDesc><biblStruct><analytic><title level="a" type="main" xml:lang="en">Transition States and Origins of 1,4‐Asymmetric Induction in Alkylations of 2,2,6‐Trialkylpiperidine Enamines</title>
<author><name sortKey="Um, Joann" sort="Um, Joann" uniqKey="Um J" first="Joann" last="Um">Joann Um</name>
<affiliation><wicri:noCountry code="subField">(+1) 310‐206‐1843</wicri:noCountry>
</affiliation>
</author>
<author><name sortKey="Kaka, Naeem" sort="Kaka, Naeem" uniqKey="Kaka N" first="Naeem" last="Kaka">Naeem Kaka</name>
<affiliation><wicri:noCountry code="subField">(+44) 1865‐285002</wicri:noCountry>
</affiliation>
</author>
<author><name sortKey="Hodgson, David" sort="Hodgson, David" uniqKey="Hodgson D" first="David" last="Hodgson">David Hodgson</name>
<affiliation wicri:level="1"><country wicri:rule="url">Royaume-Uni</country>
</affiliation>
<affiliation></affiliation>
<affiliation wicri:level="1"><country wicri:rule="url">Royaume-Uni</country>
</affiliation>
</author>
<author><name sortKey="Houk, K" sort="Houk, K" uniqKey="Houk K" first="K." last="Houk">K. Houk</name>
<affiliation wicri:level="1"><country wicri:rule="url">États-Unis</country>
</affiliation>
<affiliation></affiliation>
<affiliation wicri:level="1"><country wicri:rule="url">États-Unis</country>
</affiliation>
</author>
</analytic>
<monogr></monogr>
<series><title level="j" type="main">Chemistry – A European Journal</title>
<idno type="ISSN">0947-6539</idno>
<idno type="eISSN">1521-3765</idno>
<imprint><biblScope unit="vol">16</biblScope>
<biblScope unit="issue">21</biblScope>
<biblScope unit="page" from="6310">6310</biblScope>
<biblScope unit="page" to="6316">6316</biblScope>
<biblScope unit="page-count">7</biblScope>
<publisher>WILEY‐VCH Verlag</publisher>
<pubPlace>Weinheim</pubPlace>
<date type="published" when="2010-06-01">2010-06-01</date>
</imprint>
<idno type="ISSN">0947-6539</idno>
</series>
</biblStruct>
</sourceDesc>
<seriesStmt><idno type="ISSN">0947-6539</idno>
</seriesStmt>
</fileDesc>
<profileDesc><textClass><keywords scheme="KwdEn" xml:lang="en"><term>Aldehyde</term>
<term>Alkene</term>
<term>Alkylation</term>
<term>Alkylations</term>
<term>Allyl</term>
<term>Allyl bromide</term>
<term>Angew</term>
<term>Asymmetric induction</term>
<term>Axial</term>
<term>Axial methyl</term>
<term>Axial methyl group</term>
<term>Bromide</term>
<term>Chem</term>
<term>Conformation</term>
<term>Conformer</term>
<term>Enamine</term>
<term>Enantiomeric ratios</term>
<term>Equatorial</term>
<term>Equatorial position</term>
<term>Ethyl iodide</term>
<term>Gmbh</term>
<term>Good agreement</term>
<term>Hodgson</term>
<term>Intermolecular nucleophilic substitution</term>
<term>Isopropyl</term>
<term>Isopropyl enamine</term>
<term>Isopropyl group</term>
<term>Kgaa</term>
<term>Lone interaction</term>
<term>Lone pair</term>
<term>Methyl</term>
<term>Methyl enamine</term>
<term>Model enamines</term>
<term>Olefinic protons</term>
<term>Phys</term>
<term>Piperidine</term>
<term>Piperidine ring</term>
<term>Preferential attack</term>
<term>Relative enthalpies</term>
<term>Transition state</term>
<term>Transition states</term>
<term>Transition structures</term>
<term>Unfavorable interaction</term>
<term>Verlag</term>
<term>Verlag gmbh</term>
<term>Weinheim</term>
<term>Weinheim chem</term>
</keywords>
<keywords scheme="Teeft" xml:lang="en"><term>Aldehyde</term>
<term>Alkene</term>
<term>Alkylation</term>
<term>Alkylations</term>
<term>Allyl</term>
<term>Allyl bromide</term>
<term>Angew</term>
<term>Asymmetric induction</term>
<term>Axial</term>
<term>Axial methyl</term>
<term>Axial methyl group</term>
<term>Bromide</term>
<term>Chem</term>
<term>Conformation</term>
<term>Conformer</term>
<term>Enamine</term>
<term>Enantiomeric ratios</term>
<term>Equatorial</term>
<term>Equatorial position</term>
<term>Ethyl iodide</term>
<term>Gmbh</term>
<term>Good agreement</term>
<term>Hodgson</term>
<term>Intermolecular nucleophilic substitution</term>
<term>Isopropyl</term>
<term>Isopropyl enamine</term>
<term>Isopropyl group</term>
<term>Kgaa</term>
<term>Lone interaction</term>
<term>Lone pair</term>
<term>Methyl</term>
<term>Methyl enamine</term>
<term>Model enamines</term>
<term>Olefinic protons</term>
<term>Phys</term>
<term>Piperidine</term>
<term>Piperidine ring</term>
<term>Preferential attack</term>
<term>Relative enthalpies</term>
<term>Transition state</term>
<term>Transition states</term>
<term>Transition structures</term>
<term>Unfavorable interaction</term>
<term>Verlag</term>
<term>Verlag gmbh</term>
<term>Weinheim</term>
<term>Weinheim chem</term>
</keywords>
</textClass>
</profileDesc>
</teiHeader>
<front><div type="abstract" xml:lang="en">The asymmetric C‐alkylation of chiral enamines derived from terminal epoxides and lithium 2,2,6‐trialkylpiperidides has previously been shown to provide α‐alkylated aldehydes by intermolecular nucleophilic substitution in good levels of asymmetric induction. We now report a computational study of the origins of asymmetric induction in these reactions. Computational modeling with density functional theory (B3LYP/6‐31G(d)) agrees closely with the experimental observations. This stereoselectivity is attributed to a preferential conformation of the enamine and the piperidine ring that places the C‐6 alkyl substituent in an axial position due to A1, 3 strain. Preferential attack occurs away from the axial group, for steric reasons. The effects of changing the C‐6 substituent from methyl to isopropyl were studied, and twist transition states were found to contribute significantly in the latter alkylations.</div>
</front>
</TEI>
</record>

Pour manipuler ce document sous Unix (Dilib)

EXPLOR_STEP=$WICRI_ROOT/Wicri/Lorraine/explor/LrgpV1/Data/Main/Curation

HfdSelect -h $EXPLOR_STEP/biblio.hfd -nk 000D87 | SxmlIndent | more

HfdSelect -h $EXPLOR_AREA/Data/Main/Curation/biblio.hfd -nk 000D87 | SxmlIndent | more

Pour mettre un lien sur cette page dans le réseau Wicri

{{Explor lien
   |wiki=    Wicri/Lorraine
   |area=    LrgpV1
   |flux=    Main
   |étape=   Curation
   |type=    RBID
   |clé=     ISTEX:035F03995891F79B507BD6081B3B87643B691835
   |texte=   Transition States and Origins of 1,4‐Asymmetric Induction in Alkylations of 2,2,6‐Trialkylpiperidine Enamines
}}

This area was generated with Dilib version V0.6.32.
Data generation: Sat Nov 11 15:47:48 2017. Site generation: Wed Mar 6 23:31:34 2024

	Serveur d'exploration sur le LRGP
	Attention, ce site est en cours de développement ! Attention, site généré par des moyens informatiques à partir de corpus bruts. Les informations ne sont donc pas validées.

Serveur d'exploration sur le LRGP

Transition States and Origins of 1,4‐Asymmetric Induction in Alkylations of 2,2,6‐Trialkylpiperidine Enamines

Transition States and Origins of 1,4‐Asymmetric Induction in Alkylations of 2,2,6‐Trialkylpiperidine Enamines

Source :

English descriptors

Abstract

Links toward previous steps (curation, corpus...)

Links to Exploration step

Curation

No country items

Le document en format XML

Pour manipuler ce document sous Unix (Dilib)

Pour mettre un lien sur cette page dans le réseau Wicri