中文摘要：

以脂肪醛和丙二酸为起始原料，通过Knoevenagel缩合反应制得（E）-3-链烯酸，产率为58％-85％；（E）-3-链烯酸用双氧水和甲酸氧化后在碱性条件下关环得到3-羟基-γ-内酯，产率为80％～88％；3-羟基-γ-内酯与甲磺酰氯反应，得到3-甲磺酰氧基-γ-内酯，然后在三乙胺的作用下发生消除反应得到α，β-不饱和γ-内酯，产率为87％～90％。所有产物的结构都通过^1HNMR和^13CNMR进行了确认。该系列的化合物均呈现令人愉悦的甜香、奶香和水果香味，与相应的饱和γ一内酯相比有明显区别。

英文摘要：

A series of （E） -β - alkenoic acid was prepared via the Knoevenagel reaction of aliphatic aldehydes and malonic acid with yield of 58% - 85%. The （E） - β- alkenoie acids were oxidized by H202 and formic acid followed by ring closure in the presence of alkali and 3 - hydroxy - Y - lactones was formed with yield of 80% - 88%. The 3 - hydroxy - y - lactones were further reacted with methylsulfonyl chloride to produce 3 -methylsulfoxy -T -laetones and followed by elimination reaction with triethylamine to produce a,β-unsaturated Y - lactones with yield of 87% - 90%. The structures of all of the products were characterized by HNMR and J3CNMR. The odor features of the prepared a,β- unsaturated Y -lactones were assessed. They present pleasant sweet, milk -like and fruity aroma,which are different from that of corresponding saturated y - lactones.