regio- and stereoselective synthesis of novel trispiropyrrolidine/thiapyrrolizidines using deep eutectic solvent as an efficient reaction media

An efficient synthesis of novel trispiropyrrolidine/thiapyrrolizidines has been reported by the 1,3-dipolar cycloaddition reaction of azomethine ylides with a novel dipolarophile 8,10-bis[(e)arylidene]-3,3-dimethyl-1,5-dioxaspiro[5.5]undecan-9-one using deep eutectic solvent (des). the des is cheaper, biodegradable, non-toxic, recyclable and serves as dual role of catalyst as well as solvent. the suitable azomethine ylides were generated ‘in situ’ from the reaction of substituted isatin/acenaphthenequinone and sarcosine/1,3-thiazolane-4-carboxylic acid. in this protocol generation of one new five-membered pyrrolidine ring with three contiguous stereocenters occurred in a single operation. the stereochemistry of the synthesized compounds including regio- and diastereo was confirmed by spectroscopic techniques and single-crystal x-ray of one representative compound.