Selectivity in reduction of natural furanoheliangolides with Stryker's reagent

Abstract

Reduction of the natural sesquiterpene lactones furanoheliangolides with Stryker's reagent is an effective process for producing eremantholides through a biomimetic pathway. Other reduction products are also formed. Oxygenated functions at C-15 of the furanoheliangolide produce an increase in the velocities of the reactions and reduce the chemoselectivity of the reagent.

Rapid and scalable synthesis of chiral bromolactones as precursors to α-exo-methylene-γ-butyrolactone-containing sesquiterpene lactones

“…The secondary alcohol obtained in the course of the Barbier allylation should however readily undergo a Barton-McCombie deoxygenation. 60 Furthermore, it should be noted that sesquiterpene lactones exist at various stages of oxidation beyond the α-exo-methylene: accordingly, a wealth of further modifications of this motif are available in the literature, including epoxidation, 61 dihydroxylation, 62 conjugate reduction, 26,63 conjugate addition of C-nucleophiles, 64 ring-closing metathesis 65 or crossmetathesis, 66 to only name a few, to further extend the scope of natural products potentially reachable from these bromolactones.…”

Natural sesquiterpenoids

“…266 The anti-human glioblastoma 267,268 and anti-ulcer activities of the germacranolide tagitenin C 272 have been described. 272 270 The characterization of the cytochrome P450 component of costunolide synthase, the genes encoding it and their uses, have been patented.…”

Antimicrobial Potential of Natural and Semi-Synthetic ent-Kaurane and ent-Pimarane Diterpenes against Clinically Isolated Gram-Positive Multidrug-Resistant Bacteria

“…As part of our research interests about the evaluation of biological activities of diterpenes, 21,23 considering the semisynthesis approach 24,25 and some interesting previous results obtained in our research group, 13 we decided to perform a search for active compounds against MDR bacteria in two strands: (i) to search among natural diterpenes that could be promising skeletons due to their previous results in other activities; (ii) to modify the original structures to search for active semi-synthetic derivatives. Chosen structures were the natural diterpenes ent-kaurenoic acid (1) and ent-pimaradienoic acid (2) ( Figure 1).…”