Enantioselective total synthesis of callipeltoside A: two approaches to the macrolactone fragment
作者:David A. Evans、Jason D. Burch、Essa Hu、Georg Jaeschke
DOI:10.1016/j.tet.2008.02.001
日期:2008.5
The enantioselectivetotalsynthesis of callipeltoside A is described. Two syntheses of the macrolactone subunit are included: the first relies upon an Ireland-Claisen rearrangement to generate the trisubstituted olefin geometry and the second utilizes an enantioselective vinylogous aldol reaction for this purpose. Enantioselective syntheses of the sugar and chlorocyclopropane side chain fragments
描述了 callipeltoside A 的对映选择性全合成。包括大环内酯亚基的两种合成:第一种依赖于爱尔兰-克莱森重排来产生三取代的烯烃几何结构,第二种利用对映选择性插烯羟醛反应来实现此目的。还公开了糖和氯代环丙烷侧链片段的对映选择性合成。该天然产物的相对和绝对立体化学通过与侧链片段的两种对映异构体的片段偶联来确定。
Chlorocyclopropane Macrolides from the Marine Sponge <i>Phorbas</i> sp. Assignment of the Configurations of Phorbasides A and B by Quantitative CD
作者:Colin K. Skepper、John B. MacMillan、Guang-Xiong Zhou、Makoto N. Masuno、Tadeusz F. Molinski
DOI:10.1021/ja0703978
日期:2007.4.1
chlorocyclopropane macrolides, phorbasides A and B, have been characterized from the spongePhorbassp. that previously yielded phorboxazoles A and B. We describe the assignment of the absoluteconfiguration of the trans-chlorocyclopropane ring that exploits a CD Cotton effect arising from hyperconjugation to the ene-yne chromophore. Phorbasides and callipeltoside A share the same macrolideconfigurations but, unexpectedly
两种新的氯环丙烷大环内酯,佛巴苷 A 和 B,已从海绵 Phorbas sp. 中得到表征。先前产生佛盒唑 A 和 B。我们描述了反式氯环丙烷环的绝对构型的分配,该环利用了由于与烯-炔生色团的超共轭而产生的 CD 棉花效应。Phorbasides 和 callipeltoside A 具有相同的大环内酯构型,但出人意料的是,环丙烷构型相反。
Synchronous bond molecular dynamics of conjugated chlorocyclopropyl alk‐yn‐enes revealed by ECD and UV–vis
作者:Colin K. Skepper、Tadeusz F. Molinski
DOI:10.1002/chir.23240
日期:2020.8
Chlorocyclopropanes (CCPs) conjugated to alk‐yn‐enes occur in a unique family of polyketide natural products from marine sponges. Synthesis of several optically enriched analogs of CCPs and measurement of their UV–vis spectra and electronic circular dichroism (ECD) spectra reveal unusually strong hyperconjugation that constrains and aligns the cyclopropyl C‐C bond with the π‐plane of the distal ene‐bond
Total Synthesis and Configurational Validation of (+)-Phorbaside A
作者:Ian Paterson、Tanya Paquet
DOI:10.1021/ol100693c
日期:2010.5.7
configurational assignment of the cytotoxic marinemacrolide phorbaside A has been verified by the stereodefined synthesis of the proposed structure 1 and its (18S,19R)-diastereomer 3, followed by correlation using circular dichroism spectroscopy. This first total synthesis, which proceeds in 8.2% yield over 23 steps, features two 1,4-syn boron aldol reactions, a Sonogashira coupling, and an α-glycosylation to append