Concise Formal Syntheses of the Amaryllidaceae Alkaloids (±)‐Tazettine and (±)‐6a‐Epipretazettine: Construction of the Core Skeleton via Tandem Intramolecular Oxidative Friedel–Crafts/Aza‐Michael Reaction. Issue 2 (29th November 2012)

• Record Type: Journal Article
• Authors: Ma, Donghui; Zhao, Changgui; Li, Huilin; Qi, Jing; Zhang, Ling; Xu, Shiyan; Xie, Xingang; She, Xuegong
• Is Part Of: Chemistry, an Asian journal. Volume 8:Issue 2(2013:Feb.)
• Page Start: 364
• Page End: 368
• Publication Date: 2012-11-29
• Subjects: Chemistry -- Periodicals; 540.5
• DOI: 10.1002/asia.201200964
• Languages: English
• ISSNs: 1861-4728

Abstract

<abstract abstract-type="graphical" xml:lang="en"> <title> <x xml:space="preserve">Abstract</x> </title> <p> <bold>Skeleton craft</bold>: An efficient synthesis of (±)‐(6a<italic>β</italic>)‐5‐demethyl‐6a‐deoxy‐5‐(methoxycarbonyl)tazettinone, the common core structure of (±)‐tazettine and (±)‐6a‐epipretazettine, has been accomplished in 6 steps with 54 % overall yield on a gram scale, starting from commercially available <italic>p</italic>‐hydroxybenzaldehyde and piperonyl alcohol. The requisite pentacyclic skeleton is constructed by a tandem intramolecular oxidative Friedel–Crafts/aza‐Michael reaction as the key step, which builds up two chiral centers and two rings in one step.<boxed-text content-type="graphic" position="anchor" orientation="portrait"><graphic position="anchor" mimetype="image" xlink:href="ark:/27927/pgg1tsf8z5w" orientation="portrait" xlink:type="simple" xmlns:xlink="http://www.w3.org/1999/xlink" /></boxed-text></p> </abstract>