Leon Ghosez and co-workers at CNRS in France has recently published in the ACIEE on a four component reaction to make piperidone ring systems. It involves making an aza-diene that undergoes a Diels-Alder with an alpha-beta unsaturated carbonyl component for a total of five reactions in one flask!
Archive for June, 2009
An Elegant Approach for Piperidones
Posted by naturalproductman on June 30, 2009
Posted in Cascade Reactions, Cycloaddition, Methodology, Multi-Component Coupling, Ring forming | Leave a Comment »
Enantioselective Biginelli Reaction
Posted by naturalproductman on June 30, 2009
Hee-Yoon Lee at KAIST has recently published in the European Journal of Organic Chemistry on a proline ester salt catalyzed asymmetric Biginelli reaction, which involves the coupling of an aryl aldehyde, urea, and a beta-ketoester to form a 3,4-dihydropyrimidin-2(1H)-one
(DHPM). They used a t-butoxy proline ester (20 mol%) for optimal enantioselectivity (71:29).
Posted in Cascade Reactions, Mechanistic, Methodology, Multi-Component Coupling, Organocatalytic | 1 Comment »
Erythrophlesins
Posted by naturalproductman on June 29, 2009
Masami Ishibashi and co-workers from Chiba University has recently published in Tetrahedron Letters on the isolation of erythrophlesins from Erythrophleum succirubrum. The authors did some cell viability assays with and without TRAIL (Tumor necrosis factor (TNF)-related apoptosis-inducing ligand) against human gastric adenocarcinoma (AGS) cell lines in the presence of the isolated dimers. At 10 micromlar concentration of the dimers, they noticed a significant drop (25% to 37%) in cell viability when they compared the cases with and without TRAIL.
Posted in Diterpenoids | Leave a Comment »
Bistramide
Posted by naturalproductman on June 26, 2009
David Kingston at Virginia Tech has recently published in the Journal of Natural Products on the isolation of some new anti-ovarian cancer amides, 3-oxo-bistramide K and bistramide A, from the tunicate Trididemnum cyclops.
Posted in Spiroketals, Tetrahydropyran | Leave a Comment »
Total Synthesis of Himandrine
Posted by naturalproductman on June 25, 2009
Mohammad Movassaghi from MIT has recently published a three paged communication in JACS on the total synthesis of himandrine. A key highlight of the synthesis includes an intramolecular Diels-Alder with a four-membered enamide-lactam (2-azetidinone group) substituted on the diene in order to favor the s-cis conformation and also mask the resultant ketone in the natural product. If you’ve seen his previous synthesis of galbulimima alkaloid GB-13, then you’ll notice that some of the reactions are remniscent of that synthesis. This molecule is really cool and has good history with Lew Mander being one of the pioneers in the process of discovering this molecule.
Did anybody else ever think that Professor Mander looks a little like Professor Larry Overman? Maybe it’s kind of like how GB-13 looks like himandrine.
vs.
Posted in Alkaloids | 4 Comments »