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Convergent Assembly of the Tetracyclic Meroterpenoid (−)‐Cyclosmenospongine by a Non‐Biomimetic Polyene Cyclization
Author(s) -
Speck Klaus,
Wildermuth Raphael,
Magauer Thomas
Publication year - 2016
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.201608040
Subject(s) - polyene , stereocenter , chemistry , stereochemistry , enol , convergent synthesis , ether , cationic polymerization , combinatorial chemistry , organic chemistry , enantioselective synthesis , catalysis
The cationic cyclization of polyenes constitutes a powerful and elegant transformation, which has been utilized by nature's biosynthetic machinery for the construction of complex polycyclic terpenoids. Previous studies by chemists to mimic this cyclization in the laboratory were limited to different modes of activation using biosynthetic‐like precursors, which accommodate only simple methyl‐derived substituents. Here we describe the development of an unprecedented and highly efficient polyene cyclization of an aryl enol ether containing substrate. The cyclization was shown to proceed in a stepwise manner to generate three rings and three consecutive stereocenters, two of which are tetrasubstituted, in a single flask. The developed transformation is of great synthetic value and has enabled the convergent assembly of the tetracyclic meroterpenoid (−)‐cyclosmenospongine.