Document Detail


Approach for expanding triterpenoid complexity via divergent Norrish-Yang photocyclization.
MedLine Citation:
PMID:  23544445     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Triterpenoids comprise a very diverse family of polycyclic molecules that is well-known to possess a myriad of medicinal properties. Therefore, triterpenoids constitute an attractive target for medicinal chemistry and diversity-oriented synthesis. Photochemical transformations provide a promising tool for the rapid, green, and inexpensive generation of skeletal diversity in the construction of natural product-like libraries. With this in mind, we have developed a diversity-oriented strategy, whereby the parent triterpenoids bryonolic acid and lanosterol are converted to the pseudosymmetrical polyketones by sequential allylic oxidation and oxidative cleavage of the bridging double bond at the B/C ring fusion. The resultant polyketones were hypothesized to undergo divergent Norrish-Yang cyclization to produce unique 6/4/8-fused triterpenoid analogues. The subtle differences between parent triterpenoids led to dramatically different spatial arrangements of reactive functionalities. This finding was rationalized through conformational analysis to explain unanticipated photoinduced pinacolization, as well as the regio- and stereochemical outcome of the desired Norrish-Yang cyclization.
Authors:
Vasily A Ignatenko; Gregory P Tochtrop
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Publication Detail:
Type:  Journal Article; Research Support, N.I.H., Extramural; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, Non-P.H.S.     Date:  2013-04-11
Journal Detail:
Title:  The Journal of organic chemistry     Volume:  78     ISSN:  1520-6904     ISO Abbreviation:  J. Org. Chem.     Publication Date:  2013 Apr 
Date Detail:
Created Date:  2013-04-19     Completed Date:  2013-08-12     Revised Date:  2014-04-22    
Medline Journal Info:
Nlm Unique ID:  2985193R     Medline TA:  J Org Chem     Country:  United States    
Other Details:
Languages:  eng     Pagination:  3821-31     Citation Subset:  IM    
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MeSH Terms
Descriptor/Qualifier:
Cyclization
Molecular Conformation
Photochemistry
Stereoisomerism
Triterpenes / chemistry*
Grant Support
ID/Acronym/Agency:
CA132168/CA/NCI NIH HHS; CA157735/CA/NCI NIH HHS; R01 CA157735/CA/NCI NIH HHS
Chemical
Reg. No./Substance:
0/Triterpenes
Comments/Corrections

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