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  • Open Daily: 10am - 10pm
    Alley-side Pickup: 10am - 7pm

    3038 Hennepin Ave Minneapolis, MN
    612-822-4611

Open Daily: 10am - 10pm | Alley-side Pickup: 10am - 7pm
3038 Hennepin Ave Minneapolis, MN
612-822-4611
Total Synthesis of Blennolide C and Related C4a-Functionalized Tetrahydroxanthenones

Total Synthesis of Blennolide C and Related C4a-Functionalized Tetrahydroxanthenones

Gerard, Emilie

Paperback

Series: Beiträge Zur Organischen Synthese, Book 11

Chemistry

Currently unavailable to order

ISBN10: 3832521704
ISBN13: 9783832521707
Publisher: Logos Verlag Berlin
Published: Mar 25 2009
Pages: 180
Weight: 0.60
Height: 0.48 Width: 5.68 Depth: 8.36
Language: English
Mycotoxins play an important role in the design and discovery of new biologically
active compounds. Among them, the secalonic acids represent privileged structures
because of their sparking antibiotic activities. These secondary metabolites,
belonging to a still growing family of natural products, are either symmetrical or
unsymmetrical dimers, made up of highly functionalized tetrahydroxanthenone
moieties. A similar structural motif can be found in the recently isolated
blennolide C, which is carrying a characteristic methyl ester group at the
4aposition of the tetrahydroxanthenone core. A total synthesis of this natural
product would offer a synthetic access to the basic molecular framework of this
substance class. Thus, the aim of the present work was to develop new synthetic
procedures for the total synthesis of blennolide C and related structures. In order
to achieve this goal, the reaction pathway leading to the desired substitution
pattern at the 4a-position was first investigated on a tetrahydroxanthenone model
system. Latter was efficiently substituted with olefin moieties using a
cuprate-mediated conjugate addition reaction. Further derivatization of the alkene
feature, including the Lemieux-Johnson oxidation, afforded a series of highly
functionalized xanthones. Based on these results, the total synthesis of racemic
blennolide C was successfully accomplished. The structure of this natural product,
originally wrongly attributed to i-diversonolic ester by Simpson et al., was
confirmed by X-Ray crystallography. Towards the end of this work, the true
structures of diversonolic esters were elucidated by NICOLAOU and LI.[i] Our modular
synthetic pathway developed for the total synthesis of blennolide C was then applied
to the preparation of related compounds. This allowed significant progresses towards
the total synthesis of xanthonol and secalonic acids. In conclusion, the total
synthesis of blennolide C was successfully accomplished using a modular strategy
featuring a conjugate addition of a carbonyl equivalent. The developed chemistry
allows the construction of the basic molecular framework of this class of compounds
and thus opens an expedient access to more complex natural products of the same
family.

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