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Enantioselective Total Syntheses of Pallambins A–D
Author(s) -
Zhang Xiwu,
Cai Xinxian,
Huang Bin,
Guo Lei,
Gao Zhongrun,
Jia Yanxing
Publication year - 2019
Publication title -
angewandte chemie international edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 1433-7851
DOI - 10.1002/anie.201907523
Subject(s) - enantioselective synthesis , chemistry , palladium , intramolecular force , cyclohexenone , moiety , bicyclic molecule , stereochemistry , stereoselectivity , total synthesis , wittig reaction , ring (chemistry) , lactone , combinatorial chemistry , catalysis , organic chemistry
The first enantioselective total syntheses of (−)‐pallambins A–D have been achieved in 15 or 16 steps from a known chiral cyclohexenone. Salient features of the syntheses include a palladium‐catalyzed oxidative cyclization to assemble the [3.2.1]bicyclic moiety, an Eschenmoser–Claisen rearrangement/lactone formation sequence to construct the C ring, an intramolecular Wittig reaction to form the D ring, and individual transformations of pallambins C and D to generate pallambins A and B. The described synthesis avoids protecting‐group manipulations through the design of highly chemo‐ and stereoselective transformations. During the course of this work, a palladium‐catalyzed method for the dehydrobromination of α‐bromoketones was developed, and the scope of this transformation was also investigated.