Intramolecular cycloadditions of cyclobutadiene with olefins.
J Am Chem Soc
; 124(49): 14748-58, 2002 Dec 11.
Article
em En
| MEDLINE
| ID: mdl-12465988
ABSTRACT
Intramolecular cycloadditions between cyclobutadiene and olefins can provide highly functionalized cyclobutene-containing products. The outcome of the reaction depends on the nature of the tether connecting the two reactive partners in the cycloaddition. Electronically unactivated olefins attached to cyclobutadiene through a three-atom, heteroatom-containing tether yield successfully the desired cycloadducts, whereas the corresponding substrates without a heteroatom linkage or with a longer tether are less prone to undergo the intramolecular cycloaddition. Calculations were used to help uncover some of the factors that influence the course of the cycloaddition. Successful intramolecular reactions usually require either electronic activation of the dienophile, conformational restriction of the tether, or a slower oxidation protocol. In general, a facile intermolecular dimerization of cyclobutadiene is the major process that competes with the intramolecular cycloaddition.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Hidrocarbonetos Aromáticos com Pontes
/
Ciclobutanos
/
Alcenos
Tipo de estudo:
Prognostic_studies
Idioma:
En
Ano de publicação:
2002
Tipo de documento:
Article