No abstract

Useful and easy access to highly-substituted dihydrofurans, which convert into various acetals, was established using the common Mn(III) oxidation.The key point is to use resonated vinylpentanedione radicals that cyclize to produce the desired acetoxydihydrofurans which are transformed into the hemiacetals and acetals in good yields under very mild conditions.

No abstract

The Mn­(III)-catalyzed aerobic oxidation of methylenebis­(cyclohexane-1,3-dione) enols 1 resulted in 6a-hydroxy-2,3,4,6a,7,8,9,10a-octahydro-1H-benzo­[c]­chromene-1,6,10-triones 3 during the formation of 4,5,8,10,11,12-hexahydro-2H-benzo­[b]­oxecine-2,6,7,9­(3H)-tetraones 2. The mechanism for the formation of 3 was proposed on the basis of the isolation of intermediates 2, which were transformed into 3 under Claisen and retro-Claisen conditions.