Barrier to enantiomerization of unstabilized, chelated, and dipole-stabilized 2-lithiopyrrolidines.
J Am Chem Soc
; 127(1): 449-57, 2005 Jan 12.
Article
em En
| MEDLINE
| ID: mdl-15631496
ABSTRACT
Kinetics experiments have been used to establish the free energy, enthalpy, and entropy of activation for the enantiomerization of three structural classes of 2-lithiopyrrolidines. We find that alpha-aminoorganolithiums chelated by a N-methoxyethyl or N-Boc group have a barrier to enantiomerization (DeltaG++) 2-3 kcal/mol lower than that of unstabilized alpha-aminoorganolithiums at 273 K. Density functional calculations were performed to clarify possible ground state and transition structures and to identify possible pathways for inversion of these chiral organolithium species.
Buscar no Google
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Compostos Organometálicos
/
Pirrolidinas
/
Lítio
Idioma:
En
Ano de publicação:
2005
Tipo de documento:
Article