Formal synthesis of (±)-mitsugashiwalactone and (±)-isodihydronepetalactone from norborn-5-en-2-one involving shapiro reaction

Article abstract of DOI:10.1002/jccs.199900005

A formal synthesis of (±)-mitsugashiwalactone (1) and (±)-isodihydro nepetalactone (2) was accomplished. Baeyer-Villiger lactonization of ketone 9 followed by acidic treatment led to the rearranged lactone 8, which underwent a series of functional group transformations to give cyclopentanone derivatives 19 and 20. Shapiro reaction on 21 and 22 in the presence of excess dry ice gave lactones 5 and 6. Lactones 5 and 6 previously have been converted to mitsugashiwalactone (1) and isodihydronepetalactone (2), respectively.