Preparation of furfural derived enantioenriched vinyl oxazoline building block and exploring its reactivity

N- Alloc protected furfuryl amino alcohols derived from furfural and L- or D-valinol were subjected to Torii-type ester electrosynthesis to obtain the corresponding unsaturated esters. These served as key intermediates to prepare enantioenriched ( S )- and (R)- unsaturated amides by N -Alloc deprotection which induced concomitant methoxymethyl group cleavage, O- to N- rearrangement, and isomerization of the double bond. An oxazoline ring formation in the resulting unsaturated amides provided the corresponding enantioenriched vinyl oxazolines. The reactivity of the electron deficient double bond in the vinyl oxazoline was explored in several reactions. Out of these, aza-Diels-Alder with TsNCO was successful, leading to a highly diastereoselective formation of oxazolo[3,2-c]pyrimidine derivative.