Dipeptide-catalyzed asymmetric aldol condensation of acetone with (N-alkylated) isatins.
[reaction: see text] The aldol condensation of acetone with several isatins is described. The desired compound was obtained in quantitative yield and with good enantioselectivities up to 77%. The best results were obtained with 10 mol % H-D-Pro-L-beta3-hPhg-OBn as a catalyst, resulting in the preferential formation of the (R)-enantiomer. The absolute configuration of the newly formed chiral center has been assigned by an X-ray diffraction study and CD spectra analysis of the molecules.
Luppi
Gianluigi
G
Dipartimento di Chimica G. Ciamician, Alma Mater Studiorum Università di Bologna, Via Selmi 2, 40126 Bologna, Italy.
Cozzi
Pier Giorgio
PG
Monari
Magda
M
Kaptein
Bernard
B
Broxterman
Quirinus B
QB
Tomasini
Claudia
C