Total synthesis of proposed cephalosporolides H and I
作者:Jinshan Li、Chuanfang Zhao、Jun Liu、Yuguo Du
DOI:10.1016/j.tet.2015.04.025
日期:2015.6
efficient totalsynthesis toward spiroketal diastereomers of cephalosporolides H and I was achieved, respectively, taking advantage of intramolecular Wacker-type spiroketalization on the common olefin-containing dihydroxy-γ-lactone substrate. By comparing the physical data of natural products with synthetic samples, we suggest that the reported stereochemical assignments for cephalosporolides H and I are
Stereocontrol of 5,5-Spiroketals in the Synthesis of Cephalosporolide H Epimers
作者:Sami F. Tlais、Gregory B. Dudley
DOI:10.1021/ol102201z
日期:2010.10.15
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.