中文摘要：

以N-Boc-L-酪氨酸乙酯为原料,经过酚羟基保护、酯基还原、氨基脱保护得到氨基醇,利用N,N-二甲基甲酰胺乙缩醛制备噁唑啉环,在氨基锂作用下,与硒（硫）作用分别得到（4S）-4-（4′-苄氧基）苄基-噁唑-2-硒酮和（4S）-4-（4′-苄氧基）苄基-噁唑-2-硫酮手性助剂,总产率分别为39.2%和37.9%。运用IR1、HNMR、13CNMR和元素分析等方法进行了表征,所得结果与化合物结构相符合。

英文摘要：

The novel chiral auxiliary of（4S）-4-（4′-（benzyloxyl）） benzyl oxazolones were synthesized using N-Boc-L-tyrosine ethyl ester as initiating material.From N-Boc-L-tyrosine ethyl ester,amino alcohol was obtained by three steps contained phenol hydroxyl protection,ester reduction and amino deprotection,and then it reacted with N,N-dimethyformamide diethy acetal to prepare the oxazoline ring.The oxazoline was treated by selenium or sulfur in the presence of lithium amide to obtain（4S）-4-（4′-（benzyloxyl）） benzyl oxazolidine-2-selenone or（4S）-4-（4′-（benzyloxyl）） benzyl oxazolidine-2-thione and the overall yield of the products were 39.2% and 37.9%,respectively.The structure of the target compounds were confirmed by IR,1HNMR,13CNMR,elemental analysis,and the spectrum result was consistent with the molecular structure.