Stereocontrol in the nucleophilic epoxidation of α-(1-hydroxyalkyl)-α,β-unsaturated sulfones
作者:Richard F.W. Jackson、Stephen P. Standen、William Clegg、Andrew McCamley
DOI:10.1016/s0040-4039(00)60042-4
日期:1992.10
Epoxidation of β-unsubstituted-α-(1-hydroxyalkyl)-α,β-unsaturated sulfones 3 with lithium t-butylperoxide proceeds with high diastereoselectivity to give the syn epoxy alcohols 6. Epoxidation of the triisopropylsilyl ethers 5, however, leads to the anti epoxy ethers 9 with moderate to good selectivity. In contrast to this, epoxidation of (E)-β-phenyl-α-(1-hydroxyalkyl)-α,β-unsaturated sulfones 4 proceeds
β-未取代的-α-(1-羟烷基)-α,β-不饱和的砜3与叔丁基过氧化锂的环氧化以高非对映选择性进行,得到合成环氧醇6。然而,三异丙基甲硅烷基醚5的环氧化导致具有中等至良好选择性的抗环氧醚9。与此相反,(E)-β-苯基-α-(1-羟烷基)-α,β-不饱和砜4的环氧化以高非对映选择性进行,得到抗环氧醇13。相应的三异丙基甲硅烷基醚的环氧化导致非对映选择性的逆转,从而使合成环氧醚14具有适度的选择性。提出了基于1,3-烯丙基应变原理对这些结果进行合理化的方法。