Marine polypropionates

A novel metabolite from the Chilean mollusk Siphonaria lessoni

“…Shortly after being disturbed by a potential predator, siphonariids produce a white mucus, containing polypropionate metabolites, from lateral pedal glands 1 . A feature of Siphonaria polypropionate compounds is their frequent cyclization to yield furanone, pyrone and hemi-acetal functionalities 2 . Surprisingly, the role of these compounds in the chemical ecology of Siphonaria species is poorly understood 2 .…”

Total Synthesis of Muamvatin

“…Unraveling such ring systems by hypothetical ring-chain tautomerism (after hydration in case of pyrone) leads to heavily oxygenated linear precursors with several stereogenic centers. 28,29 Considering such a linear precursor as the "starting material" and exposing it to the isolation conditions may result in spontaneous, thermodynamically controlled cyclization to one or more products. and H-C6.…”

Bioactive pyrones and flavonoids from Cryptocarya ashersoniana seedlings

“…This observation indicated that the absolute configuration a C-6 was (S) on the basis of the rule first proposed by Snatzke 18 and later modified by Beecham,19 considering the conformation of the α-pyrone ring, which was inferred due to steric factors. 20 These observations led to the establishment of the new pyrone as The biogenetic pathway leading to this novel pyrone was proposed, in which an acetate derived C 16 chain has gone through cyclization reactions to originate the pyrone ring via nucleophyllic attack followed by dehydration steps (Scheme 1). The subsequent attack of HO-5′ onto C-1′ with the ring closure via an ether linkage followed by dehydration and reduction steps might yield intermediate 8.…”