The de novo synthesis of racemic 1â²,4â²-dimethyluridine was accomplished in 12 steps starting from 2,5-dimethylfuran and vinylene carbonate. Key steps of the sequence include the stereoconvergent preparation of a meso diacid, and a stereoselective glycosylation without neighboring group participation. Such 1â²,4â²-disubstituted ribonucleoside analogues are undisclosed compounds, which may present interesting biological activities.
The Diels–Alderreactionbetween 2,5-dimethylfuran and vinylene carbonate was studied, both from an experimental and a theoretical point of view. The system was shown to slowly reach a thermodynamic equilibrium, characterized by the almost exclusive formation of the exo isomer. We rationalized these results by a comparison with classical systems involving maleicanhydride, and highlighted the different