Department of Chemistry and Biochemistry, Florida State University, Tallahassee, Florida 32306-4390, USA.
Org Lett. 2010 Oct 15;12(20):4698-701. doi: 10.1021/ol102201z.
A blueprint for controlling the stereochemistry of oxygenated 5,5-spiroketals using chelation effects is provided. Chelation specifically of zinc salts (other protic and Lewis acids were less effective) between the spiroketal oxygen and an appropriately positioned alcohol group overrides normal biases in the preparation of 5,5-spiroketals, as illustrated by the stereocontrolled synthesis of epimeric cephalosporolide H isomers. This study provides new and valuable information for prescribing the chirality of the stereogenic core of 5,5-spiroketals.
提供了一种使用螯合效应控制含氧 5,5-螺缩酮立体化学的蓝图。螯合作用（其他质子酸和路易斯酸的效果较差）特别在螺缩酮氧和适当位置的醇基团之间螯合，可覆盖在制备 5,5-螺缩酮时的正常偏差，如立体控制合成差向 Cephalosporolide H 异构体所示。这项研究为规定 5,5-螺缩酮立体中心的手性提供了新的有价值的信息。
