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Total Synthesis of Crotophorbolone
Author(s) -
Asaba Taro,
Katoh Yuki,
Urabe Daisuke,
Inoue Masayuki
Publication year - 2015
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.201509160
Subject(s) - chemistry , stereocenter , total synthesis , stereochemistry , stille reaction , ring (chemistry) , isomerization , olefin fiber , hydroxylation , bond cleavage , alkoxy group , steric effects , derivative (finance) , enantioselective synthesis , catalysis , organic chemistry , alkyl , financial economics , economics , enzyme
The complex ABC‐tricyclic structure of crotophorbolone, a derivative of the tigliane diterpenoids, was assembled by coupling of simple fragments. The six‐membered C‐ring fragment, having five contiguous stereocenters, was stereoselectively constructed from ( R )‐carvone. After attachment of the five‐membered A‐ring through the π‐allyl Stille coupling reaction, the α‐alkoxy bridgehead radical reaction effected the endo ‐cyclization of the seven‐membered B‐ring by forming the sterically congested bond at C9 and C10 stereospecifically and stereoselectively, respectively. Finally, the functional groups on the 5/7/6‐membered ring system were manipulated by rhodium‐catalyzed C2 olefin isomerization, C13 decarboxylative oxidation, and C4 hydroxylation, thus completing the first total synthesis of crotophorbolone.