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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
Author(s) -
Ma Donghui,
Zhao Changgui,
Li Huilin,
Qi Jing,
Zhang Ling,
Xu Shiyan,
Xie Xingang,
She Xuegong
Publication year - 2013
Publication title -
chemistry – an asian journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.18
H-Index - 106
eISSN - 1861-471X
pISSN - 1861-4728
DOI - 10.1002/asia.201200964
Subject(s) - intramolecular force , tandem , amaryllidaceae alkaloids , chemistry , michael reaction , yield (engineering) , total synthesis , friedel–crafts reaction , skeleton (computer programming) , stereochemistry , organic chemistry , catalysis , computer science , alkaloid , materials science , metallurgy , composite material , programming language
Skeleton craft : An efficient synthesis of (±)‐(6a β )‐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 p ‐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.