[structure: see text] A stereocontrolled convergent synthesis of the annonaceous acetogenin pyragonicin (1) is presented. The key intermediates were accessed using asymmetric Horner-Wadsworth-Emmons (HWE) methodology. A reagent controlled zinc-mediated stereoselective coupling, joining the two highly functionalized intermediates 3 and 4, then provided the core structure.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1021/ol050997g | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
SmI2-induced cyclizations and their applications in natural product synthesis.
Chem Rec
June 2010
Department of Chemistry, Faculty of Science, Tokyo University of Science, 1-3 Kagurazaka, Shinjuku-ku, Tokyo162-8601, Japan.
Since the isolation of brevetoxin-B, a red tide toxin, many bioactive marine natural products featuring synthetically challenging trans-fused polycyclic ether ring systems have been reported. We have developed SmI(2)-induced cyclization of beta-alkoxyacrylate with aldehyde, affording 2,6-syn-2,3-trans-tetrahydropyran (THP) or 2,7-syn-2,3-trans-oxepane with complete stereoselection, as a key reaction of efficient iterative and bi-directional strategies for the construction of these polycyclic ethers. This reaction is also applicable to the synthesis of 3-, 5-, and 6-methyl-THPs and 3,5-dimethyl-THP.
View Article and Find Full Text PDFPyranicin, a non-classical annonaceous acetogenin, is a potent inhibitor of DNA polymerase, topoisomerase and human cancer cell growth.
Int J Oncol
February 2008
RIKEN (The Institute of Physical and Chemical Research), Wako-shi, Saitama, Japan.
This report describes the inhibitory activities of the natural and non-natural acetogenins [mucocin (compound 1), jimenezin (compound 2), 19-epi jimenezin (compound 3), muconin (compound 4), pyranicin (compound 5), pyragonicin (compound 6), 10-epi pyragonicin (compound 7), and a gamma-lactone (compound 8)], which were synthesized by us, against DNA polymerase (pol), DNA topoisomerase (topo), and human cancer cell growth. Among the compounds tested, compound 5 was revealed to be the strongest inhibitor of the animal pols and human topos tested, and the IC50 values for pols and topos were 2.3-15.
View Article and Find Full Text PDFConvergent synthesis of pyragonicin.
J Org Chem
August 2006
RIKEN (The Institute of Physical and Chemical Research), Wako-shi, Saitama, 351-0198, Japan.
This paper describes a second-generation synthesis of an antitumor tetrahydropyran (THP) acetogenin, pyragonicin. The key step involved an olefin cross-metathesis between the THP segment and the terminal gamma-lactone residue. The coupling reaction in the presence of Grubbs' second-generation catalyst resulted in an unseparable mixture of a desired coupling product and its one-carbon eliminated product while the use of Grubbs' first-generation catalyst afforded the former exclusively.
View Article and Find Full Text PDFDivergence en route to nonclassical annonaceous acetogenins. Synthesis of pyranicin and pyragonicin.
J Org Chem
March 2006
KTH Chemical Science and Engineering, Organic Chemistry, SE-100 44 Stockholm, Sweden.
Syntheses of the nonclassical annonaceous acetogenins, pyranicin, and pyragonicin from common late-stage intermediates are presented. The construction of key elements relies on asymmetric HWE reactions, including the desymmetrization of a meso-dialdehyde and a parallel kinetic resolution of a racemic aldehyde. A stereoconvergent Pd-catalyzed substitution serves to install the C4 stereocenter in protected form with different orthogonal protective groups.
View Article and Find Full Text PDFTotal synthesis of the proposed structure for pyragonicin.
Org Lett
June 2005
RIKEN (The Institute of Physical and Chemical Research), Wako, Saitama 351-0198, Japan.
[structure: see text] The total synthesis of acetogenin 1 reported for pyragonicin and its 10-epimer 32 is described. The common THP ring system was stereoselectively constructed through a SmI(2)-induced reductive cyclization of beta-alkoxy acrylate 5 followed by Mitsunobu inversion, and each chiral center at C-10 was created by Brown's asymmetric allylation. Compound 1 had spectroscopic data consistent with that of natural pyragonicin, but a different optical rotation.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!