Ammonia-Promoted Fragmentation Of 2-Alkyl- And 2,4-Dialkyl-3-Iodo-1-Oxocyclohexan-2,4-Carbolactones

2-Alkyl- and 2,4-dialkyl-3-iodo-1-oxocyclohexan-2,4-carbolactones undergo ammonia-promoted fragmentation reactions to provide butenolides, gamma-butyrolactone, and/or, beta,gamma-epoxycyclohexanones. Product distribution is governed by the relative size of the substituents at C-2 and C-4 of the cyclohexanones. Butenolide amide, the major product from the fragmentation, is further converted into their respective piperidinone and pyrrolidine derivatives.