abstract |
13-cis-retinoic acid is obtained by the Wittig reaction of a [3-methyl-5- (2,6,6-trimethyl-1-cyclohexen-1-yl) -2,4-pentadienyl] phosphonium salt with 5-hydroxy-4 -methyl-2 (5H) furanone at low temperatures and isomerization of the resulting mixture of 13-cis and 11,13-di-cis isomers by means of certain Pd or Rh catalysts. |