Synthesis of 9‐cis‐retinoic acid and C‐20‐[3H3C]‐9‐cis‐retinoic acid with high specific activity

The synthesis of 9-cis-retinoic acid starting from 2,2,6-trimethylcyclohexanone is described. The same methodology was extended for the synthesis of deuterium and tritium labeled 9-cis-retinoic acid with high specific activity (73 Ci/mmol). In this methodology, a Grignard reaction was utilized for introducing three tritium atoms simultaneously in the final synthetic steps. © 1997 John Wiley & Sons, Ltd.