Proto- and iodo-lactonization reaction of substituted α,β: γ,δ- unsaturated carboxylic acid

Article abstract of DOI:10.1246/bcsj.72.1583

Iodolactonization of 4,5-disubstituted 2-(trimethylsilylmethyl)- and 2- methyl-penta-2,4-dienoic acids was studied. The latter afforded the corresponding iodolactone in good yield by treatment with I₂ in MeCN. Iodolactone was also obtained by treatment with I₂/NaHCO₃/CHCl₃/H₂O in the presence of cerium(IV) salt as an additive. It was found that protolactonization proceeds by the aid of the trimethylsilyl group, while it prevents iodolactonization.