Dedicated to Professor Dieter Enders.
Abstract
The synthesis of polyfunctionalized indolizidines from pipecolinic acid alkyl ester
derivatives, aldehydes and a wide range of dipolarophiles by multicomponent 1,3-dipolar
cycloadditions is developed in a diastereoselective manner. The cycloadditions take
place in toluene with short reaction times at 70 °C, giving good yields. The synthesis
of these fused heterocycles is also studied starting from pipecolinic acid, generating
the dipole through a decarboxylative route at 120 °C. The relative configuration of
the resulting products as well as the mechanistic pathways are also explained.
Key words
cycloaddition - multicomponent - indolizidines - azomethine ylides - iminium route
- decarboxylative route