This communication reports a significant breakthrough on the novel catalytic amide allylation to the acyclic α-ketoester systems, achieving satisfactorily high yields and extremely high levels of the asymmetric induction to allow for highly enantioselective synthesis of ester functionalised α-methylene-γ-butyrolactones.
Construction of Spiro-Fused 2-Oxindole/α-Methylene- γ-Butyrolactone Systems with Extremely High Enantioselectivity via Indium-Catalyzed Amide Allylation of <i>N</i>-Methyl Isatin
A remarkably effective method allowing an extremely high enantioselectivesynthesis of the spiro-fused 2-oxindole/α-methylene-γ-butyrolactones is described. The key strategy lies in the use of indium-catalyzed asymmetric amideallylation of N-methyl isatin with functionalized allylstannanes, which can lead to the antineoplastic spirocyclic lactones in almost enantiopure forms.