The synthesis of the S1-N10 nine-membered lactone core 28 of ent-griseoviridin is reported. Starting from cystine derivative 25, encompassing a terminal ynoate, treatment under Zn/ AcOH conditions led to the formation of lactone 28 in 12% yield. Therefore, the lactone moiety of ent-griseoviridin is obtained in 10.7% overall yield for two steps. An access to the corresponding 5-epi-griseoviridin lactone
A promising precursor of marineosins A and B, unusual macrocyclic pyrrole and spiroiminal alkaloids isolated from marine microorganism has been synthesized employing a direct coupling of pyrrole and delta-lactone.
Preparation of <i>syn</i>-δ-Hydroxy-β-amino Esters via an Intramolecular Hydrogen Bond Directed Diastereoselective Hydrogenation. Total Synthesis of (3<i>S</i>,4a<i>S</i>,6<i>R</i>,8<i>S</i>)-Hyperaspine
作者:Wei Zhu、Dawei Ma
DOI:10.1021/ol036097m
日期:2003.12.1
Hydrogenation of delta-hydroxy-beta-ketoester-derived enamines 8 produces syn-delta-hydroxy-beta-amino esters 9 diastereoselectively, which may be directed by the formation of an intramolecularhydrogenbond between the delta-hydroxyl and beta-amino groups. By using this method and a Dieckmann reaction as the key steps, (3S,4aS,6R,8S)-hyperaspine, a new type of ladybird alkaloid, is synthesized. [reaction:
Production of novel bispyrone metabolites in the cellular slime mold Dictyostelium giganteum induced by zinc(II) ion
作者:Van Hai Nguyen、Haruhisa Kikuchi、Hiraku Sasaki、Kyoichi Iizumi、Yuzuru Kubohara、Yoshiteru Oshima
DOI:10.1016/j.tet.2016.12.040
日期:2017.2
study, Zn2+ induced the production of two new bispyrone-type metabolites, dictyobispyrone B and E, in the cellular slimemold Dictyostelium giganteum. Their structures were proposed on the basis of spectroscopic analysis and confirmed by chemical synthesis. They possess a novel α,α-bispyrone skeleton modified with long carbon chains. Both could be formed from two different polyketide chains through a