Conformationally Constrained Oxides of 1,3-Dithiane: Synthesis and NMR Spectroscopic Investigations
作者:Roland Ulshöfer、Tobias Wedel、Bastian Süveges、Joachim Podlech
DOI:10.1002/ejoc.201200675
日期:2012.12
regardless of whether there is an axial or an equatorial sulfoxide, sulfide or sulfone group present in between the respective C–H moieties. A previously postulated γ-gauche effect of axial sulfoxides (but not of equatorial sulfoxides or sulfones) leading to the shielding of carbon atoms is not unambiguously supported by the NMR spectroscopic data of conformationally fixed derivatives.
1,3-二噻烷的构象受限衍生物(5-叔丁基-和4,6-二甲基-1,3-二噻烷和二噻烷)已被各种氧化剂氧化,生成轴向和赤道亚砜、二亚砜和砜。轴向亚砜是通过将亲核氢氧化物加成到相应的 2-亚烷基衍生物上并随后进行反羟醛型消除来制备的。正如 DFT 计算所证明的那样,反应结果与衍生物的相对能量有关。分析所得化合物的NMR光谱数据以鉴定4J偶联。发现无论在各自的 C-H 部分之间是否存在轴向或赤道亚砜、硫化物或砜基团,都只能观察到 4J W 耦合。