General procedure for the synthesis of (S)-tetrahydronaphthalenecarboxylic acid from 1,2,3,4-tetrahydro-1-naphthalenecarboxylic acid: 15.6 g (0.1 mol) of 1,2,3,4-tetrahydronaphthalenecarboxylic acid and 29.8 g (0.1 mol) of quinine were added to 158 mL of a 50% (v/v) aqueous ethanol solution, and stirred for 30 min at 50 °C until complete dissolution. The progress of the reaction was monitored by thin layer chromatography (TLC) with the unfolding agent ratio of petroleum ether (PE):ethyl acetate (EA) = 1:2. Upon completion of the reaction, the reaction solution was cooled to below 0 °C overnight to promote crystallization. Subsequent to filtration, the solid was collected and dried. The dried solid was recrystallized with 90 mL of ethanol, crystallized again at 0 °C, diafiltrated and dried. The resulting product was dissolved in a mixture of 55 mL of 1 mol/L hydrochloric acid and 100 mL of ethyl acetate in a partitioning operation. The organic phase was dried and filtered and concentrated to obtain the crude product. Finally, the crude product was recrystallized from hexane to give 7.21 g of (S)-1,2,3,4-tetrahydronaphthalenecarboxylic acid in the form of white solid in 43.6% yield.
