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Total Synthesis of Marine Sesquiterpene Quinones (+)‐Cyclospongiaquinone‐1 and (–)‐Dehydrocyclospongiaquinone‐1 with a Tetracyclic Benzo[ a ]xanthene Skeleton
Author(s) -
Takeda Yuki,
Narita Koichi,
Katoh Tadashi
Publication year - 2017
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/ejoc.201601160
Subject(s) - chemistry , moiety , xanthene , decalin , stereochemistry , total synthesis , dihydropyran , stereocenter , pyran , cyclopentenone , sesquiterpene , organic chemistry , enantioselective synthesis , catalysis
Two marine sesquiterpene quinones, (+)‐cyclospongiaquinone‐1 and (–)‐dehydrocyclospongiaquinone‐1, were efficiently synthesized in 10 and 12 steps and overall yields of 33 and 24 %, respectively, from commercially available (+)‐sclareolide. The synthetic strategy involves the following crucial steps: (i) assembly of the carbon skeleton by coupling the decalin segment to the aromatic moiety; (ii) one‐step construction of the dihydropyran ring by acid‐induced acetonide deprotection/ether cyclization of an olefinic decalin intermediate that contains the aromatic moiety; (iii) formation of the p ‐benzoquinone moiety by oxidation of a p ‐methoxyphenolic derivative to produce (+)‐cyclospongiaquinone‐1; and (iv) oxidative dehydrogenation at the C‐12–C‐12a bond of a tetracyclic intermediate to obtain (–)‐dehydrocyclospongiaquinone‐1.