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Coupling of Sterically Hindered Trisubstituted Olefins and Benzocyclobutenones by CC Activation: Total Synthesis and Structural Revision of Cycloinumakiol
Author(s) -
Xu Tao,
Dong Guangbin
Publication year - 2014
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.201404802
Subject(s) - steric effects , epimer , chemistry , natural product , olefin fiber , total synthesis , stereochemistry , catalysis , olefin metathesis , combinatorial chemistry , organic chemistry , metathesis , polymer , polymerization
The first total syntheses of the proposed structure of cycloinumakiol ( 1 ) and its C5 epimer ( 18 ) are achieved in a concise and efficient fashion. Starting from the known 3‐hydroxybenzocyclobutenone, 1 and 18 are obtained in nine and five steps with overall yields of 15 % and 33 %, respectively. The key for the success of this approach is the use of a catalytic CC activation strategy for constructing the tetracyclic core of 1 through carboacylation of a sterically hindered trisubstituted olefin with benzocyclobutenone. In addition, the structure of the natural cycloinumakiol was reassigned to 19‐hydroxytotarol ( 7 ) through X‐ray diffraction analysis. This work demonstrates the potential of CC activation for streamlining complex natural product synthesis.