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Synthesis and Structure Revision of Dichrocephones A and B
Author(s) -
Schmiedel Volker M.,
Hong Young J.,
Lentz Dieter,
Tantillo Dean J.,
Christmann Mathias
Publication year - 2018
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.201711766
Subject(s) - stereocenter , enantioselective synthesis , propellane , chemistry , stereochemistry , stereoselectivity , total synthesis , wittig reaction , combinatorial chemistry , catalysis , bicyclic molecule , organic chemistry
Herein, we report the first enantioselective synthesis of dichrocephones A and B, which are cytotoxic triquinane sesquiterpenes with a dense array of stereogenic centers within a strained polycyclic environment. Key features include the application of a catalytic asymmetric Wittig reaction, followed by stereoselective functionalization of the propellane core into a pentacyclic intermediate. Double reductive ring cleavage yielded the proposed structure of dichrocephone A. Mismatched spectroscopic data for our synthetic material compared to the natural isolate led us to revise the previously proposed configuration based on biosynthetic considerations and NMR calculations. Implementation of these findings culminated in the synthesis of dichrocephones A and B.