Naturalproductman’s Blog

Hey, is that a natural product?!

Cordigol Progress

Posted by naturalproductman on February 9, 2010

Alan Spivey and co-workers at Imperial College have recently published in Organic Letters on a SnCl4-mediated Prins cyclization to form the ring system of cordigol.

prins

OL paper

Posted in Cascade Reactions, Eschenmoser-Tanabe fragmentation, Methodology, Named Reactions, Prins | Leave a Comment »

Three Component Approach for Cyclic Nitrones

Posted by naturalproductman on February 9, 2010

Milan Potacek and co-workers at Masaryk University have recently published in Tetrahedron on a three component coupling approach for synthesizing 5-membered-cyclic nitrones.

nitrones

Tetrahedron paper

Posted in Allenes, Cascade Reactions, Methodology, Multi-Component Coupling, Ring forming | Leave a Comment »

Tangutorine Synthesis

Posted by naturalproductman on February 8, 2010

Here’s a nice alkaloid total synthesis by Yasumasa Hamada and co-workers at Chiba University.

tangutorine

OL paper

Posted in Cascade Reactions, Methodology, Named Reactions, Palladium, Pictet-Spengler, Ring forming, Transition Metal | Leave a Comment »

A Failed Inverse Electron Demand Diels-Alder

Posted by naturalproductman on February 8, 2010

Craig Lindsley and co-workers at Vanderbilt have recently published in Organic Letters on their attempt at an inverse electron demand Diels-Alder reaction to access marineosin.  That reaction would have been cool if they got it to work.  It’s interesting that they published a failed biosynthetic proposal route – but fortunately they are not giving up on the synthesis and now they are going to approach the synthesis with a different route.

marineosin

OL paper

Posted in Cascade Reactions, Diels-Alder, Methodology, Named Reactions | Leave a Comment »

[5+2] then Nazarov

Posted by naturalproductman on February 8, 2010

Paul Wender and co-workers have recently published in JACS on a rhodium catalyzed [5+2] cycloaddition followed by Nazarov protocol.

5+2

JACS paper

Posted in Cascade Reactions, Cycloaddition, Electrocyclization, Methodology, Named Reactions, Nazarov cyclization, Rhodium, Transition Metal | Leave a Comment »

Synthesis of Chloptosin

Posted by naturalproductman on February 5, 2010

Zhu-Jun Yao and co-workers at the Shanghai Institute of Organic Chemistry have recently published in Organic Letters on the total synthesis of a C2-symmetric cyclopeptide, chloptosin, which induces apoptosis in human pancreatic adenocarcinoma cell lines AsPC-1 with an EC50 of 2.5 micrograms per mL.  This molecule is an important lead because many human carcinoma cells are resistant to apoptosis.

chloptosin

OL paper

Posted in Dimer, Macrocycles, Methodology, Peptides | Leave a Comment »

Vinylogous Aldol

Posted by naturalproductman on February 5, 2010

Masahiro Terada and co-workers at Tohoku University have used an organocatalytic approach to perform vinylogous Aldol reactions using a C2-symmetric guanidine base.

guanidine

ACIEE paper

Posted in Aldol, Asymmetric, Cascade Reactions, Methodology, Named Reactions, Organocatalytic | Leave a Comment »

Idesolide Synthesis

Posted by naturalproductman on February 5, 2010

Yoshiharu Iwabuchi and co-workers at Tohoku University have recently published in Organic Letters on the synthesis of idesolide from a dimerization of a cyclohexenone starting material.  The dimerization step involved the use of AZADO (2-azaadamantane-N-oxyl).

idesolide

OL paper

AZADO paper

Posted in Cascade Reactions, Dimer, Methodology, Organocatalytic, Radical Chemistry, Ring forming | Leave a Comment »

Cyanolide A

Posted by naturalproductman on February 5, 2010

William Gerwick and co-workers at UC San Diego have recently published in the Journal of Natural Products on the isolation of cyanolide A, a glycosidic macrolide, from the bacteria, Lyngbya bouillonii, from Papua, New Guinea. This dimeric macrolide was found to kill molluscs – specifically Biomphalaria glabrata with an LC50 of 1.2 micromolar. This biological activity is important because these snails carry parasites that cause schistosomiasis.

cyanolide A

JNP paper

Posted in Dimer, Macrolides | Leave a Comment »

Multi-Component Fe-Catalysis

Posted by naturalproductman on February 4, 2010

Umasish Jana and co-workers at Jadavpur University in India have recently published in JOC on a multicomponent approach towards substituted pyrroles using an iron (III) catalyst.

iron

JOC paper

Posted in Cascade Reactions, Iron, Methodology, Multi-Component Coupling, Transition Metal | Leave a Comment »