𝔖 Bobbio Scriptorium
✦   LIBER   ✦

Lactone synthesis via the intramolecular alkylation of β-keto ester dianions

✍ Scribed by Russell J. Sims; Samuel A. Tischler; Larry Weiler

Publisher
Elsevier Science
Year
1983
Tongue
French
Weight
192 KB
Volume
24
Category
Article
ISSN
0040-4039

No coin nor oath required. For personal study only.

✦ Synopsis

Long chain m-halo B-keto esters yield macrocyclic B-keto lactones. British Columbia, Vancouver, B.C., Canada V6T lY6 undergo intramolecular alkylation via the dianions to Since the isolation of exaltolide (pentadecanolide) by Kerschbauml fifty-five years ago, a large number of macrocyclic lactones have been isolated from a variety of sources. We were interested in the synthesis of macrocyclic B-keto lactones which are the skeletal subunit in the antiobiotics narbomycin2 and diplodialide A3. Partial reduction of the keto group would give Bhydroxy lactones. Recently two components of the defense secretion of the termite Armitermes neotenicus have been identified as very large-ring B-hydroxy lactones4. Finally complete reduction of the keto group would give the musk lactones5.

📜 SIMILAR VOLUMES

Aldol reactions of the dianion of β-keto
Aldol reactions of the dianion of β-keto esters
✍ S.N. Huckin; Larry Weiler 📂 Article 📅 1971 🏛 Elsevier Science 🌐 French ⚖ 169 KB

Recently we developed an efficient proceedure to alkylate B-keto esters at the Y carbon. 1 This involved treating the starting 8-keto ester with one equivalent of sodium hydride, then with one equivalent of n-butyllithium to give the dianion &, and finally alkylation at the more nucleophilic termin

A synthesis of ynolates via the cleavage
A synthesis of ynolates via the cleavage of ester dianions
✍ Mitsuru Shindo 📂 Article 📅 1997 🏛 Elsevier Science 🌐 French ⚖ 199 KB

A new method for ynolate synthesis via the cleavage of ester dianions has been developed. The key intermediates, ester dianions, generated from ct-bromocarboxylic acid ester enolates via lithiumhalogen exchange turned out to be so labile that they were cleaved rapidly to give ynolates.