Regioselective synthesis of α,α-dialkylcyclopentanones from 1-hydroxycyclobutanecarboxylic acid or from O-protected cyclobutanone cyanohydrin

Article abstract of DOI:10.1016/S0040-4020(98)00448-7

1-(1-Hydroxyalkyl)cyclobutanols 4a-f, readily available either from 1-hydroxycyclobutane carboxylic acid or from O-protected cyclobutanone cyanohydrin, appeared the most suitable precursors for a regioselective synthesis of cyclopentanones α,α- disubstituted with various similar or different alkyl, alkenyl, aryl or cycloalkyl groups. The key steps consist of acid or Grignard reagent induced C₄→C₅ ring expansions.