The present invention relates to processes for the preparation of 5-methyl-3-nitromethyl-hexanoic acid ester and its salts. Also disclosed are processes for the preparation of 5-methyl-3-nitromethyl-hexanoic acid salt and a process for the preparation of 3-(aminomethyl)-5-methylhexanoic acid. (S)-5-Methyl-3-nitromethyl-hexanoic acid or (R)-5-methyl-3-nitromethyl-hexanoic acid in enantioenriched form or enantiopure form as well as salts thereof, (S)-5-methyl-3-nitromethyl-hexanoic acid ester or (R)-5-methyl-3-nitromethyl-hexanoic acid ester in enantioenriched form or enantiopure form and a compound, namely Formula (XIII), in racemic form, enantioenriched form or enantiopure form are also disclosed.