by the regio- and stereoselective ring opening of β, γ, and δ-lactones with unsaturated substituents at the ω-position using organocopperreagents such as halomagnesium diorganocuprates or Grignard reagents in the presence of copper(I) iodide. Both the organocopperreagents with primary, secondary, tertiary alkyl, and phenyl groups gave the corresponding carbon homologated alkenoic acids in good yields
Simple methods for the syntheses of (E)-4- and (E)-5-alkenoic acids by the SN2′ type reactions of γ-vinyl-γ-butyrolactone and δ-vinyl-δ-valerolactone with organocopper reagents