硫元素由于多变的价态以及强的成键能力使其在自然界的存在形式非常丰富，例如硫醚，二硫醚，亚磺酸，次磺酸，硫代亚磺酸酯，硫代硫酸酯，亚硫酸酯，硫酸盐等。硫醚结构片段也是许多药物的重要组成部分，因此，发展构建C-S键的不同策略显得格外重要。我们采用羰基α-位亲电硫化与亲核硫化两种策略，分别实现了羰基化合物α-位的不对称烷基硫化反应以及基于AOAC中间体的硫化反应及不对称环化反应，主要研究结果如下：

合成了以噻二唑为骨架的新型烷基硫化试剂，并将其应用在β-羰基化合物的不对称硫化反应中。该反应以高区域选择性、高对映选择性得到了烷基硫醚产物，具有广泛的底物适用性，为手性烷基硫醚的合成提供了新方法。

利用氮杂氧代烯丙基阳离子（AOAC）中间体作为亲电试剂与硫醇生成了硫醚产物，以高区域选择性实现了AOAC与硫醇的亲核取代反应。对于手性条件下对映选择性的控制还需进一步的研究。此外我们利用AOAC作为亲电试剂与环状酮酯底物发生环加成反应，生成了手性并环产物，实现了对AOAC不对称环化反应的初步探索。

Due to the variable valence states and strong bonding ability of sulfur element, sulfur containing organic compounds exist in various forms, such as thioethers, disulfides, sulfides, thiosulfites, sulfites and sulfates, etc. Thioether fragments can serve as important components of many drugs and bioactive compounds. Thus, the development of constructing strategies for thioethers is quite important. In this thesis, α-alkylsulfenylation reaction, sulfidation and asymmetric cyclization reactions of carbonyl compounds via AOAC intermediates were achieved with the two strategies of electrophilic sulfenylation and nucleophilic sulfenylation. The main research results are shown as following:

(1) A novel alkyl sulfuration reagent with thiadiazole was developed and applied to β-asymmetric sulfuration of carbonyl compounds with high regioselectivities and enantioselectivities. This reaction system can be applied with a wide range of carbonyl compounds, which can be used as novel method for asymmetric synthesis of chiral alkyl sulfide compounds.

(2) Thioether products could be provided through the reaction of aza-oxyallylic cation (AOAC) intermediate with mercaptan as a nucleophilic reagent with high regioselectivities. Further asymmetric exploration is now under going in our lab. Cycloaddition reaction of AOAC with the cyclic ketone ester substrates was carried out to produce chiral cyclic products. Preliminary exploration of asymmetric cyclization reaction of AOAC has been achieved.