Lithium Hexamethyldisilazide-Mediated Enolization of Acylated Oxazolidinones: Solvent, Cosolvent, and Isotope Effects on Competing Monomer- and Dimer-Based Pathways.
J Am Chem Soc
; 139(3): 1233-1244, 2017 01 25.
Article
em En
| MEDLINE
| ID: mdl-28080036
ABSTRACT
Lithium hexamethyldisilazide (LiHMDS)-mediated enolization of (+)-4-benzyl-3-propionyl-2-oxazolidinone in THF-hydrocarbon mixtures shows unusual sensitivity to the choice of hydrocarbon cosolvent (hexane versus toluene) and to isotopic labeling. Four mechanisms corresponding to monosolvated monomers, trisolvated dimers, octasolvated monomers, and octasolvated dimers were identified. Even under conditions in which the LiHMDS monomer was the dominant observable form, dimer-based metalation was significant. The mechanism-dependent isotope and cosolvent effects are discussed in the context of ground-state stabilization and transition-state tunneling.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Silanos
/
Tolueno
/
Compostos de Lítio
/
Oxazolidinonas
/
Furanos
/
Hexanos
Idioma:
En
Ano de publicação:
2017
Tipo de documento:
Article