2-Hydroxyethyl enol ethers react with Re2O7 to produce 2-hydroxyketals. Where homochiral starting enol ethers are employed, greater than 99:1 diastereoselectivities are obtained. The stereocontrol is rationalized by invoking a transition state that approximates the geometry of a metallaoxetane. Finally, homochiral ketals are themselves oxidized to provide 2-hydroxyketals with high diastereoselectivity
2-羟乙基烯醇醚与Re 2 O 7反应生成2-羟基
缩酮。当使用均手性起始烯醇醚时,获得大于99∶1的非对映选择性。通过调用近似
金属氧杂
环丁烷的几何形状的过渡态,可以合理地控制立体控制。最后,将手性
缩酮本身氧化以提供具有高非对映选择性的2-羟基
缩酮。