A mixture of N—((S)-6-bromo-1,2,3,4-tetrahydronaphthalen-2-yl)-4-cyclopropylmethoxy-benzamide (5.20 g) and THF (120 ml) was cooled to −78° C. (dry ice bath), and a solution of methyllithium (8.9 ml; 1.6 M in diethyl ether) was added dropwise. One minute after the addition had ended, a solution of butyllithium (5.7 ml; 2.5 M in toluene) was added dropwise. One minute after the addition had ended, DMF (2.85 g) and, after a further 30 seconds, acetic acid (1.5 ml) were added. After warming to room temperature, the reaction mixture was diluted with water and extracted with ethyl acetate. The organic phases were dried over magnesium sulfate and concentrated. The product was thus obtained with the molecular weight of 349.43 (C22H23NO3); MS (ESI): 350 (M+H+). 4-Butoxy-N—((S)-6-formyl-1,2,3,4-tetrahydronaphthalen-2-yl)benzamide can also be prepared analogously.
