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Updated: Jan 17, 2026

A Two-Step Protocol for Umpolung Functionalization of Ketones Via Enolonium Species
Published on: August 16, 2018
Total Synthesis of Alanense B via Stereoselective Enolate Alkylation
Jun-Ya Matsumoto1, Shunsuke Sueki1,2, Kosho Makino1,2
1Faculty of Pharmacy, Musashino University, Nishitokyo, Tokyo 202-8585, Japan.
Abstract:
A total synthesis of (±)-alanense B, a unique and unprecedented 2-aryl substituted cadinane-type sesquiterpenoid that exhibits spontaneous calcium channel oscillations in primary cultured neocortical neurons, has been accomplished. Intramolecular Friedel-Crafts acylation and enolate methylation using KHMDS in 1,2-dimethoxyethane yielded the pentasubstituted 1-tetralone bearing a quaternary stereogenic center at the C2 position with complete diastereoselectivity. Cleavage of three phenolic methyl ethers prior to DDQ oxidation was essential for reaching the final product.
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