A double decarboxylation reaction of an oxazolidinone and carboxylic Acid: its application to the synthesis of a new opioid lead compound.

Treatment of oxazolidinone carboxylic acid 6 with potassium carbonate gave olefin 7 by a double decarboxylation reaction. The reaction was proposed to proceed via decarboxylation followed by E1cB-like mechanism. 15,16-Nornaltrexone derivative 17 prepared from double decarboxylation product 7 showed strong affinity for the μ opioid receptor, indicating it to be a new opioid lead compound.