all living organisms produce only one enantiomer so we found that all natural compounds are presented in enantiomerically pure form. Asymmetric synthesis is highly spread in pharmaceutical industry because enantiomerically pure drugs are highly applicable. Most of traditional drugs that used for treatment of many diseases are usually undergo racemic modifications of two enantiomers, and the side effect of these drugs is due to presence of the un wanted enantiomer. The asymmetric synthesis has become very important to increase the enantioselectivity of synthesized compounds via different methods. This study demonstrated the enantioselective synthesis of (S)-2-ethylpentanoic acid (5a, b) and (R)- 2-ethylpentanoic acid (5c, d) using quinazolinone derivative (2) as chiral auxiliaries. The enantiomeric excess was determined via HPLC using silica gel column and ranging from 90-98 depending on different factors. Some of the synthesized compounds were examined in-vitro against different types of bacteria and fungi and give a good result.