Total Synthesis of Purported Cephalosporolides H and I, Penisporolide B, and Their Stereoisomers
作者:Jian Wang、Rongbiao Tong
DOI:10.1021/acs.joc.6b00788
日期:2016.5.20
β-hydroxy cyclic ethers and dehydrative ring-contraction rearrangement of 10-membered lactones. Synthetic utility of this strategy was demonstrated by total syntheses of 12 Me2SAFLs, corresponding to the purported cephalosporolide H (CesH), cephalosporolide I (CesI), and penisporolide B (PenB) and their possible diastereomers. Comprehensive NMR data analysis suggested that the tricyclic Me2SAFL core of
据报道,开发了一种统一的,受生物启发的合成策略,以获取独特的2,2-二甲基-[5,5]-螺缩醛-顺式-融合-γ-内酯的四种可能的非对映体(Me 2 SAFL),其特征在于吡啶鎓氯铬酸盐(PCC)促进β-羟基环醚的氧化环扩张和10元内酯的脱水环收缩重排。通过合成12个Me 2 SAFL证明了该策略的合成效用,分别对应于声称的头孢菌素H(CesH),头孢菌素I(CesI)和Penisporolide B(PenB)及其可能的非对映异构体。全面的NMR数据分析表明,应将CesH,CesI和PenB的三环Me 2 SAFL核修改为相同的相对值(3 R *,4R *,6 S *,9 R *)构型,并且侧链需要未知的结构修订。
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.