The addition of n-butyllithium to alkenylthiocarbamates in the presence of (-)-sparteine or the (+)-sparteine surrogate leads to asymmetric carbolithiation, and returns enantiomerically enriched thiocarbamate derivatives of secondary thiols. In THF, with the (+)-sparteine surrogate, in situ aryl migration leads to an enantiomerically enriched tertiary thiol derivative. Remarkably, the two pseudoenantiomeric chiral ligands do not always give enantiomeric products, probably as a result of a complex interplay of kinetic and thermodynamic control. In situ IR and NMR studies of a stable, hindered lithiated thiocarbamate demonstrated its chemical and configurational stability over a period of hours at 0 °C. This journal is
Enantioselective carbolithiation of S-alkenyl-N-aryl thiocarbamates: Kinetic and thermodynamic control
DEGENNARO, LEONARDO;LUISI, Renzo
;
2015-01-01
Abstract
The addition of n-butyllithium to alkenylthiocarbamates in the presence of (-)-sparteine or the (+)-sparteine surrogate leads to asymmetric carbolithiation, and returns enantiomerically enriched thiocarbamate derivatives of secondary thiols. In THF, with the (+)-sparteine surrogate, in situ aryl migration leads to an enantiomerically enriched tertiary thiol derivative. Remarkably, the two pseudoenantiomeric chiral ligands do not always give enantiomeric products, probably as a result of a complex interplay of kinetic and thermodynamic control. In situ IR and NMR studies of a stable, hindered lithiated thiocarbamate demonstrated its chemical and configurational stability over a period of hours at 0 °C. This journal isFile | Dimensione | Formato | |
---|---|---|---|
castagnolo2015.pdf
non disponibili
Tipologia:
Documento in Post-print
Licenza:
NON PUBBLICO - Accesso privato/ristretto
Dimensione
2.82 MB
Formato
Adobe PDF
|
2.82 MB | Adobe PDF | Visualizza/Apri Richiedi una copia |
I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.