The first synthetic study towards the natural product pestalone (1) is described culminating in the preparation of selected n-1 analogues. Pestalone is a chlorinated and prenylated benzophenone antibiotic, which is of interest due to a strong activity against methicillin-resistant staphylococcus aureus strains (MRSA). Key step of the synthesis is the nucleophilic addition of a highly functionalized aryllithium building block to a 2-prenylated 3,5-dialkoxy-benzaldehyde followed by oxidation. For the introduction of the prenyl sidechain by aryl-allyl coupling, different procedures were evaluated, among them the Stille reaction and a nickel pi-allyl complex coupling. (C) 2003 Elsevier Ltd. All rights reserved.
for the rearrangement reaction; however, at such temperatures, the substrate decomposed. To address this issue, we added phenylethylamine or benzylamine to the reaction system. We assumed that the amine trapped generated hydrochloric acid and acted as a ligand for iron, helping to maintain an appropriate redox potential. The totalsynthesis of dendrochrysanene, involving this rearrangement reaction
Enantioselective total synthesis of aigialomycin D
作者:Jiangping Lu、Junying Ma、Xingang Xie、Bo Chen、Xuegong She、Xinfu Pan
DOI:10.1016/j.tetasy.2006.03.027
日期:2006.4
An efficient, convergent approach for the total synthesis of aigialomycin D I is described. Key features of the synthetic strategy include (a) a Sharpless asymmetric epoxidation reaction and selective opening of a 2,3-epoxy alcohol to elaborate the two hydroxy-bearing stereogenic centers at the C5' and C6' positions; (b) a Kocienski modified Julia protocol to construct the two E-configured double bonds; and (c) Yamaguchi macrolactonization to acccess the 14-membered macrocyclic ring. (c) 2006 Elsevier Ltd. All rights reserved.