Ruthenium tetroxide (1 mol%) has been used as a catalyst for the oxidative mono-cyclization of 1,5,9-trienes and polyenes. The poly-unsaturated substrates underwent mono-cyclization with a high degree of diastereo- and positionselectivity to produce mono-tetrahydrofuran diols with a varying degree of unsaturation. Up to four new stereogenic centers were created in this single step transformation. The remarkable positionselectivity appears to be a result of relative electronic properties of the double bonds within the polyolefinic substrates in conjunction with conformational constraints.
过
氧化钌(1毫摩尔%)被用作1,5,9-
三烯和多烯的氧化单环化反应的催化剂。多不饱和底物经历了具有高程度的Diastereo选择性和位点选择性的单环化反应,生成了不同程度不饱和的单烯
四氢呋喃二醇。在这一单步转化中,最多可以创造四个新的立体中心。显著的位点选择性似乎是由于聚烯烃底物中双键的相对电子特性与构象约束的结合所导致的。