The Effect of Sulfoxides on the Stereoselective Construction of Tetrahydrofurans: Total Synthesis of (+)-Goniothalesdiol
作者:Gloria Hernández-Torres、M. Carmen Carreño、Antonio Urbano、Françoise Colobert
DOI:10.1002/chem.201002637
日期:2011.1.24
Good to excellent stereoselectivities were achieved in the reductive cyclization (with Et3SiH/trimethylsilyl trifluoromethanesulfonate (TMSOTf)) of enantiopure hydroxy sulfinyl ketones en route to 2,5‐cis‐disubstituted tetrahydrofuran skeletons. Electrostatic effects of the exocyclic sulfoxide, which stabilized the reactive intermediate oxocarbenium conformations, were responsible for the observed
对映体纯的羟基亚磺酰基酮在2,5-顺式-二取代的四氢呋喃骨架的还原环化反应中(用Et 3 SiH /三甲基甲硅烷基三氟甲磺酸盐(TMSOTf))达到了良好的立体选择性。环外亚砜的静电作用使反应性中间体氧碳鎓构象稳定,这是观察到的立体控制的原因。提出了一个模型来解释结果。使用该反应和不对称还原β-酮亚砜作为关键步骤,促进了天然β-C-芳基糖苷(+)-goniothalesdiol的全部对映选择性合成。