PREPARATION OF FIVE- AND SIX- MEMBERED CYCLIC KETONES BY THE PALLADIUM-CATALYZED CYCLIZATION REACTION. APPLICATION TO METHYL DIHYDROJASMONATE SYNTHESIS

Article abstract of DOI:10.1016/S0040-4039(00)92750-3

Methyl 3-oxo-8-phenoxy-6-octenoate (1) was cyclized using Pd(OAc)2-PPh3 as a catalyst to give 2-carbomethoxy-3-vinylcyclopentanone (2) and 2-carbomethoxy-4-cycloheptenone (3).The former was the main product in acetonitrile. 2-Alkylated 3-oxo-8-phenoxy-6-octenoates were converted mainly to the five-membered ketones.Based on this cyclization method, methyl dihydrojasmonate (8) was prepared from methyl 2-pentyl-3-oxo-8-phenoxy-6-octenoate (5).Methyl 3-oxo-9-phenoxy-7-nonenoate (10) was subjected to the palladium-catalysed cyclization to afford 2-carbomethoxy-3-vinylcyclohexanone (11) selectively without forming the eight membered ketone (12).