A Facile Method for Synthesis of Three Carbon-Homologated Carboxylic Acid by Regioselective Ring-opening of β-Propiolactones with Organocopper Reagents

Article abstract of DOI:10.1016/0040-4020(89)80068-7

Organocopper reagents, such as diorganocuprates, organocopper-tributylphosphine, and Grignard reagents in the presence of a copper (I) salt, reacted with β-propiolactones by regioselective β-carbon-oxygen fission to give 3-substituted propionic acids.Among these three kinds of organocopper reagents, diorganocuprate, especially halomagnesium cuprate gave the highest yields of the acids, which was remarkably observed in the ring-opening of sterically hindered β-propiolactones such as β-methyl- and α,β-dimethyl-β-propiolactones and also in the reactions using the organocopper reagents with vinyl and allyl substituents.The ring-opening of β-propiolactone was confirmed to proceed by SN2 pathway with predominant inversion of configuration of the β-carbon by using the reaction of cis-α,β-dimethyl-β-propiolactone with di-tert-butylcuprate to afford syn-2,3,4,4-tetramethylpentanoic acid.