Document Detail


Enantioselective halocyclization of polyprenoids induced by nucleophilic phosphoramidites.
MedLine Citation:
PMID:  17314976     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Polycyclic bio-active natural products that contain halogen atoms have been isolated from a number of different marine organisms. The biosynthesis of these natural products appears to be initiated by an electrophilic halogenation reaction at a carbon-carbon double bond via a mechanism that is similar to a proton-induced olefin polycyclization. Enzymes such as haloperoxidases generate an electrophilic halonium ion (or its equivalent), which reacts with the terminal carbon-carbon double bond of the polyprenoid, enantioselectively inducing a cyclization reaction that produces a halogenated polycyclic terpenoid. Use of an enantioselective halocyclization reaction is one possible way to chemically synthesize these halogenated cyclic terpenoids; although several brominated cyclic terpenoids have been synthesized via a diastereoselective halocyclization reaction that uses stoichiometric quantities of a brominating reagent, the enantioselective halocyclization of isoprenoids induced by a chiral promoter has not yet been reported. Here we report the enantioselective halocyclization of simple polyprenoids using a nucleophilic promoter. Achiral nucleophilic phosphorus compounds are able to promote the diastereoselective halocyclization reaction to give a halogenated cyclic product in excellent yields. Moreover, chiral phosphoramidites promote the enantioselective halocyclization of simple polyprenoids with N-iodosuccinimide to give iodinated cyclic products in up to 99% enantiomeric excess and diastereomeric excess. To the best of our knowledge, this is the first successful example of the enantioselective halopolycyclization of polyprenoids.
Authors:
Akira Sakakura; Atsushi Ukai; Kazuaki Ishihara
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Nature     Volume:  445     ISSN:  1476-4687     ISO Abbreviation:  Nature     Publication Date:  2007 Feb 
Date Detail:
Created Date:  2007-02-22     Completed Date:  2007-03-19     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  0410462     Medline TA:  Nature     Country:  England    
Other Details:
Languages:  eng     Pagination:  900-3     Citation Subset:  IM    
Affiliation:
Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa, Nagoya 464-8603, Japan.
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MeSH Terms
Descriptor/Qualifier:
Biomimetics
Catalysis
Cyclization
Halogens / chemistry*
Iodine / chemistry
Organophosphorus Compounds / chemistry*
Peroxidases / metabolism
Substrate Specificity
Chemical
Reg. No./Substance:
0/Halogens; 0/Organophosphorus Compounds; 0/phosphoramidite; 7553-56-2/Iodine; EC 1.11.1.-/Peroxidases
Comments/Corrections
Comment In:
Nature. 2007 Feb 22;445(7130):826-7   [PMID:  17314962 ]

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