Related Experiment Video
Updated: Jul 17, 2026

A Direct, Early Stage Guanidinylation Protocol for the Synthesis of Complex Aminoguanidine-containing Natural Products
Published on: September 9, 2016
A short, formal, biomimetic synthesis of (+/-)-polygalolides A and B
Barry B Snider1, Xiaoxing Wu, Seiichi Nakamura
1Department of Chemistry MS 015, Brandeis University, Waltham, Massachusetts 02454-9110, USA. snider@brandeis.edu
Abstract:
[reaction: see text] Reaction of bisacetoxy pyranone 9 with Et3N gave 3-oxidopyrylium ylide 10, which underwent a stereo- and regiospecific [5 + 2] cycloaddition with alpha-methylenebutyrolactone to afford 16 (34%). Treatment of 16 with Cs2CO3 resulted in hydrolysis of the lactone and acetate and conjugate addition of the hydroxyethyl group to the enone. Lactonization on acidification afforded 4 (57%), completing a two-step, formal synthesis of polygalolides A and B.
Related Concept Videos
Step-Growth Polymerization: Overview
Many natural and synthetic polymers are produced by...
Polymers
Molecular Weight of Step-Growth Polymers
As the step-growth polymerization involves step-wise condensation of monomers, the molecular weight also builds up eventually. Consequently, high molecular weight polymers are obtained at the late stages of the polymerization, where 99% of monomers have been consumed.
The extent of the...

