Sur une possibilite d'acces aux cetones macrocycliques par les ene-allenes

Ene-allenes can be valuable precursors for the obtention of bicyclic enones, key-intermediates for the synthesis of macrocyclic ketones like exaltone and muscone.     

Oxydes d'allenes VI (1). migration-1,4 de fonction lors de l'oxydation selective de derives d'alcools α-alleniques. Synthese de dienones conjuguees.

The oxydation of α-allenic acetates affords conjugated dienones whereas α-allenic trimethylsilyl ethers give rise to silyl ethers of unsaturated α-cetols. A ?1,4 migration of the function is involved.     

Study of structural and electronic transport properties of Ce-doped LaMnO3

The structural and electronic transport properties of La_1−x Ce _x MnO₃ (x=0.0–1.0) have been studied. All the samples exhibit orthorhombic crystal symmetry and the unit cell volume decreases with Ce doping. They also make a metal-insulator transition (MIT) and transition temperature increases with increase in Ce concentration up to 50% doping. The system La_0.5Ce_0.5MnO₃ also exhibits MIT instead of charge-ordered state as observed in the hole doped systems of the same composition.