A process for the preparation of enantiomerically pure -methyl-1,2,3,4-tetrahydroquinoline comprising the following steps: a) transforming quinoline-3-carboxylic acid into the corresponding C 1 -C 4 linear or branched alkyl or aryl ester, wherein aryl is a phenyl or benzyl moiety, optionally substituted with one or more C 1 -C 4 linear or branched alkyl groups; b) reducing said ester to the corresponding (R,S)-1,2,3,4-tetrahydroquinoline-3-carboxylate ester; c) reducing said (R,S)-1,2,3,4-tetrahydroquinoline-3-carboxylate ester to obtain (R,S)-3-(1'-hydroxy-methyl)-1,2,3,4-tetrahydroquinoline; d) protecting the amino group of said (R,S)-3-(1'-hydroxy-methyl)-1,2,3,4-tetrahydroquinoline using di-tertbutyl carbonate to obtain (R,S)-3-(1'-hydroxy-methyl)-1-tertbutyloxycarbonyl-1,2,3,4-tetrahydroquinoline; e) submitting the racemic mixture of (R,S)-3-(1'-hydroxy-methyl)-1-tertbutyloxycarbonyl-1,2,3,4-tetrahydroquinoline to a first transesterification catalyzed by Pseudomonas fluorescens lipase in a toluenic solution using an ester of vinyl alcohol with a C 2 -C 8, linear or branched alkyl carboxylic acid as acyl donor, wherein the reaction is stopped at a PFL rate of conversion comprised between 30 and 40% to obtain isomer S of the corresponding (R,S)-3-(1'-carboalkoxy-methyl)-1-tertbutyloxycarbonyl-1,2,3,4-tetrahydroquinoline, which is subsequently hydrolyzed by PFL enzyme at a rate of conversion comprised between 60 and 75% to obtain the corresponding enantiomerically pure -3-(1'-hydroxy-methyl)-1-tertbutyloxycarbonyl-1,2,3,4-tetrahydroquinoline; f) transforming the obtained compound -3-(1'-hydroxy-methyl)-1-tertbutyloxycarbonyl-1,2,3,4-tetrahydroquinoline with a sulphonyl chloride R"-SO 2 -Cl, wherein R" is a C 1 -C 4 linear or branched alkyl, phenyl, optionally substituted by one or more methyl groups thus obtaining the corresponding sulphonyl derivative; g) reducing said sulphonyl derivative to the corresponding -3-methyl-1-tertbutyloxycarbonyl-1,2,3,4-tetrahydroquinoline using a hydride; h) removing the protective group of the amino nitrogen atom to obtain the corresponding, enantiomerically pure synthon -3-methyl-1,2,3,4-tetrahydroquinoline. a) transforming quinoline-3-carboxylic acid into the corresponding C 1 -C 4 linear or branched alkyl or aryl ester, wherein aryl is a phenyl or benzyl moiety, optionally substituted with one or more C 1 -C 4 linear or branched alkyl groups; b) reducing said ester to the corresponding (R,S)-1,2,3,4-tetrahydroquinoline-3-carboxylate ester; c) reducing said (R,S)-1,2,3,4-tetrahydroquinoline-3-carboxylate ester to obtain (R,S)-3-(1'-hydroxy-methyl)-1,2,3,4-tetrahydroquinoline; d) protecting the amino group of said (R,S)-3-(1'-hydroxy-methyl)-1,2,3,4-tetrahydroquinoline using di-tertbutyl carbonate to obtain (R,S)-3-(1'-hydroxy-methyl)-1-tertbutyloxycarbonyl-1,2,3,4-tetrahydroquinoline; e) submitting the racemic mixture of (R,S)-3-(1'-hydroxy-methyl)-1-tertbutyloxycarbonyl-1,2,3,4-tetrahydroquinoline to a first transesterification catalyzed by Pseudomonas fluorescens lipase in a toluenic solution using an ester of vinyl alcohol with a C 2 -C 8, linear or branched alkyl carboxylic acid as acyl donor, wherein the reaction is stopped at a PFL rate of conversion comprised between 30 and 40% to obtain isomer S of the corresponding (R,S)-3-(1'-carboalkoxy-methyl)-1-tertbutyloxycarbonyl-1,2,3,4-tetrahydroquinoline, which is subsequently hydrolyzed by PFL enzyme at a rate of conversion comprised between 60 and 75% to obtain the corresponding enantiomerically pure -3-(1'-hydroxy-methyl)-1-tertbutyloxycarbonyl-1,2,3,4-tetrahydroquinoline; f) transforming the obtained compound -3-(1'-hydroxy-methyl)-1-tertbutyloxycarbonyl-1,2,3,4-tetrahydroquinoline with a sulphonyl chloride R"-SO 2 -Cl, wherein R" is a C 1 -C 4 linear or branched alkyl, phenyl, optionally substituted by one or more methyl groups thus obtaining the corresponding sulphonyl derivative; g) reducing said sulphonyl derivative to the corresponding -3-methyl-1-tertbutyloxycarbonyl-1,2,3,4-tetrahydroquinoline using a hydride; h) removing the protective group of the amino nitrogen atom to obtain the corresponding, enantiomerically pure synthon -3-methyl-1,2,3,4-tetrahydroquinoline.