The MDM2/p53 is one of the most widely studied protein-protein interaction because of being a valuable target for the development of novel anticancer agents. MDM2 protein is the natural inhibitor of p53 protein which act as a tumor suppressor. When MDM2 is overexpressed, damaged DNA is allowed to replicate and therefore cancerous cells can be generated because p53 has lost of its activity. For this reason; maintaining the activity of wild-type p53 through inhibition of MDM2 can stop the proliferation of cancer cells. New drugs that inhibit this interaction are important for the treatment of cancer. The aim of the study is synthesize chiral 1,4-oxazepine-5-one derivatives. (R)-2-amino-2-(4-chlorophenyl)acetic acid was used as starting material for the synthesis. The first step was a trityl protection of amine with trityl chloride. Trityl protected amino acid was reduced to N-Trt amino alcohol with LiAlH4 then oxidized to aldehyde by using Dess-Martin periodinane. The resulting aldehyde was reacted with 3-chlorophenylmagnesium bromide. Up to this part of the synthesis, reactions were performed successfully. Then trityl group was removed by TFA and amino alcohol was obtained. Then addition of several α,β-unsaturated carbonyls to the deprotected amino alcohol was studied by coupling reagents such as HATU. Afterwards we performed some intramolecular cyclization attempts but all cyclization attempts were failed.