Styryl lactones, which are compounds isolated from natural sources, are known for their cytotoxic property against variety cancer cell lines. Goniothalamin is a well known member of stryl lactones, include α,β-unsaturated δ-lactone in its structure. Being a α,β-unsaturated δ-lactone subunit is an important structural feature. Since, Goniothalamin has a selective cytotoxic property for cancer cell lines with no significant cytotoxic activity toward non-malignant cells. Recent studies show that naphthalen-1-yl substituted α,β-unsaturated δ-lactone derivative has slightly better cytotoxic activity than (R)-goniothalamin. As a result of that naphthalen-1-yl substituted α,β-unsaturated δ-lactones derivative was named as klavuzon by Çağır Research group. In this study it is aimed to synthesize 4’-alkyl substituted klavuzon derivatives. Syntheses were started with the Cu catalayzed addition of Grignard reagents to ethyl 4-(bromomethyl)-1-naphthoate to achieve alkyl substitution. For lactone synthesis a well-known three steps synthesis was used starting from aldehyde. Thus 1-naphthoate esters first reduced to alcohol then oxidized to aldehyde by using LiAlH4 and PCC. These aldehydes were reacted with allymagnesium bromide then formed alcohols were acrylated with acryloyl chloride to yield the corresponding esters. Finally, target molecules were synthesised by ring closing metathesis by using 2nd generation Grubbs’ catalyst.