A practical and cost-effective synthesis of 6,7-dimethoxy-2-tetralone

The cyclic ketone, 6,7-dimethoxy-2-tetralone, a versatile starting material for many dopaminergic compounds, can be prepared practically, cost-effectively and in good overall yield. The synthesis starts from readily available 3,4-dimethoxyphenylacetic acid. Ring iodination gave the 2-iodo-4,5-dimethoxy acid, which was converted to its methyl ester. Palladium (II)-catalyzed Heck cross coupling afforded the expected unsaturated diester, which was then catalytically hydrogenated. Dieckmann condensation, followed by careful decarboxylation led to the desired 2-tetralone. Reagents used in subsequent reactions are inexpensive and readily available. This method appears practical for large-scale synthesis of the target tetralone, compared with other procedures reported in the literature.