Highly enantioselective electrophilic amination and michael addition of cyclic beta-ketoesters induced by lanthanides and (S,S)-ip-pybox: the mechanism.
High enantioselection is obtained in Michael additions of cyclic beta-ketoesters in the presence of lanthanium triflates and (S,S)-ip-pybox. Intermediates based on simultaneous coordination of the lanthanide to both (S,S)-ip-box and beta-ketoester (in keto and enolate forms) are detected by means of ESI mass spectrometry and NMR experiments, and a possible mechanism is proposed through theoretical calculations.
Comelles
Josep
J
Department of Chemistry, Universitat Autonoma de Barcelona, Cerdanyola, 08193-Barcelona, Spain.
Pericas
Alex
A
Moreno-Mañas
Marcial
M
Vallribera
Adelina
A
Drudis-Solé
Galí
G
Lledos
Agusti
A
Parella
Teodor
T
Roglans
Anna
A
García-Granda
Santiago
S
Roces-Fernández
Laura
L