The reaction of cyclic beta-keto esters with CF3CO2ZnCH2I provided the corresponding ring-expanded products in moderate to good yields. Although alpha-substituted acyclic beta-keto esters reacted with much less efficient, chain-extension reaction of simple beta-keto esters also proceeded effectively to generate gamma-keto esters in high yields.
SHONO, TATSUYA;KISE, NAOKI;UEMATSU, NOBUYUKI;MORIMOTO, SHINJI;OKAZAKI, EI+, J. ORG. CHEM., 55,(1990) N7, C. 5037-5041