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Total Syntheses of Juglorescein and Juglocombins A and B
Author(s) -
Kamo Shogo,
Yoshioka Kai,
Kuramochi Kouji,
Tsubaki Kazunori
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.201604765
Subject(s) - chemistry , epoxide , hydroquinone , intramolecular force , stereocenter , total synthesis , lactone , ring (chemistry) , quinone , stereochemistry , derivative (finance) , hydrolysis , naphthoquinone , organic chemistry , enantioselective synthesis , catalysis , financial economics , economics
Abstract Total syntheses of juglorescein and juglocombins A and B are reported. The highly oxygenated 6/6/5/6/6‐fused pentacyclic ring system of these natural products was constructed through a bioinspired dimerization of 1,4‐naphthoquinone. Notably, five new stereogenic centers were constructed in a single step by the dimerization reaction. The epoxide intermediate obtained from the dimerization was successfully converted into juglocombins A and B through photoinduced reduction of the epoxide, dehydration, and conversion of the resultant quinone into a hydroquinone derivative. The same epoxide intermediate was also converted into a dicarboxylic acid, which was transformed into juglorescein through intramolecular lactonization, hydrolysis of the resulting lactone, and removal of the protecting groups. Furthermore, the relative and absolute configurations of juglorescein and juglocombins A and B were determined.