A cooperative chiral guanidine/Ag(I) catalyst system was developed for the asymmetric
isocyanoacetate aldol reaction with isatins. The corresponding chiral spirooxindole
oxazolines were obtained in good yields (up to 99%), moderate diastereoselectivities
(up to 88:12 dr) and good enantioselectivities (up to 90% ee).
Key words
aldol reaction - cooperative catalysis - isatins - isocyanoacetates - guanidine