English   español  
Please use this identifier to cite or link to this item: http://hdl.handle.net/10261/37219
Share/Impact:
Statistics
logo share SHARE logo core CORE   Add this article to your Mendeley library MendeleyBASE

Visualizar otros formatos: MARC | Dublin Core | RDF | ORE | MODS | METS | DIDL
Exportar a otros formatos:
Title

Stereoselective, Temperature-Dependent [2+2] Cycloaddition of N,N-Dialkylhydrazones to N-Benzyl-N-(benzyloxycarbonyl)aminoketene

AuthorsMarqués-López, Eugenia ; Martín-Zamora, Eloísa; Díez, Elena; Fernández, Rosario; Lassaletta, José M.
KeywordsAsymmetric synthesis
Cycloaddition
Hydrazones
Lactams
Antibiotics
Issue Date29-Apr-2008
PublisherWiley-VCH
CitationEuropean Journal of Organic Chemistry (17): 2960-2972 (2008)
AbstractThe Staudinger-like [2+2] cycloaddition of aliphatic hydrazones derived from (2R,5R)-1-amino-2,5-dimethylpyrrolidine to N-benzyl-N-(benzyloxycarbonyl)aminoketene takes place to afford the corresponding β-lactams in good yields when iPr2EtN is used as the base. The reaction proceeds in all cases with excellent stereocontrol to afford exclusively products having the (3R) configuration. Temperature was observed to exert a strong influence on the cis/trans selectivity, allowing in most cases the obtention of single trans or cis cycloadducts simply by performing the reactions at 80 °C or room temperature, respectively. Additional experiments support the hypothesis that the observed stereochemistry is the result of C=N isomerization in the zwitterionic intermediate, which takes place by a nucleophilic addition―rotation―elimination mechanism effected by the nucleophiles present in the reaction medium. Release of the dialkylamino group by oxidative cleavage of the N–N bond affords valuable compounds such as α,β-diamino acids and the azetidinone cores of monobactam antibiotics such as aztreonam and carumonam.
Description13 páginas, 1 figura, 3 tablas, 9 esquemas.
Publisher version (URL)http://dx.doi.org/10.1002/ejoc.200800194
URIhttp://hdl.handle.net/10261/37219
DOI10.1002/ejoc.200800194
ISSN1434-193X
E-ISSN1099-0690
Appears in Collections:(IIQ) Artículos
Files in This Item:
There are no files associated with this item.
Show full item record
Review this work
 

Related articles:


WARNING: Items in Digital.CSIC are protected by copyright, with all rights reserved, unless otherwise indicated.