Document Detail


Rotational isomers of N-methyl-N-arylacetamides and their derived enolates: implications for asymmetric Hartwig oxindole cyclizations.
MedLine Citation:
PMID:  23534372     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
The rotational preferences of N-(2-bromo-4,6-dimethylphenyl)-N-methyl 2-phenylpropanamide were studied as a model of precursors for Hartwig asymmetric oxindole cyclizations. The atropisomers of this compound were separated by flash chromatography, and then the enantiomers were resolved and the interconversions of the stereocenter and the N-Ar axis were studied. Under thermal conditions, the axis is very stable. Under the basic conditions of the Hartwig cyclization, both the stereocenter and the chiral axis equilibrate via enolate formation. The N-Ar rotation barrier of a 2-phenylacetamide analogue was reduced from 31 kcal mol(-1) in the precursor to 17 kcal mol(-1) in the enolate. Reasons for this dramatic barrier reduction and implications of both N-Ar and amide C-N rotations for Hartwig cyclizations are discussed.
Authors:
Jérémie Mandel; Xiaohong Pan; E Ben Hay; Steven J Geib; Craig S Wilcox; Dennis P Curran
Publication Detail:
Type:  Journal Article; Research Support, N.I.H., Extramural; Research Support, U.S. Gov't, Non-P.H.S.     Date:  2013-04-09
Journal Detail:
Title:  The Journal of organic chemistry     Volume:  78     ISSN:  1520-6904     ISO Abbreviation:  J. Org. Chem.     Publication Date:  2013 Apr 
Date Detail:
Created Date:  2013-04-19     Completed Date:  2013-08-12     Revised Date:  2014-04-22    
Medline Journal Info:
Nlm Unique ID:  2985193R     Medline TA:  J Org Chem     Country:  United States    
Other Details:
Languages:  eng     Pagination:  4083-9     Citation Subset:  IM    
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MeSH Terms
Descriptor/Qualifier:
Benzeneacetamides / chemistry*
Cyclization
Indoles / chemistry*
Phenylpropionates / chemistry*
Stereoisomerism
Grant Support
ID/Acronym/Agency:
R37 GM033372/GM/NIGMS NIH HHS; S10 RR023404/RR/NCRR NIH HHS; S10 RR031789/RR/NCRR NIH HHS
Chemical
Reg. No./Substance:
0/Benzeneacetamides; 0/Indoles; 0/N-(2-bromo-4,6-dimethylphenyl)-N-methyl 2-phenylpropanamide; 0/Phenylpropionates; 0/oxindole
Comments/Corrections

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