Intramolecular Cycloadditions and Thermal Rearrangement of Cyclopropylidene Nitrones. Straightforward Access to Bicyclic Tetrahydropyridones

Article abstract of DOI:10.1016/0040-4039(94)02473-O

The intramolecular cycloaddition of cyclopropylidene nitrones (1 and 2) gives the "fused" adducts exclusively or predominantly over the "bridged" adduct (2:1).The "fused" adducts posses the cyclopropyloxy functionality which is prone to undergo a selective thermal rearrangement.The adducts 10 and 11 rearrange by heating in solution at 140 deg C and 160 deg C, respectively, to give the bicyclic tetrahydropyridones 13 and 14.