Document Detail


6,6-Dicyanopentafulvenes: Electronic Structure and Regioselectivity in [2+2] Cycloaddition-Retroelectrocyclization Reactions.
MedLine Citation:
PMID:  23043246     Owner:  NLM     Status:  Publisher    
Abstract/OtherAbstract:
We present an investigation of the electronic properties and reactivity behavior of electron-accepting 6,6-dicyanopentafulvenes (DCFs). The EPR spectra of the radical anion of a tetrakis(silylalkynyl) DCF, generated by Na metal reduction, show delocalization of both the charge and unpaired electron to the nitrogens of the cyano moieties and also, notably, to the silicon atoms of the four alkynyl moieties. By contrast, in the radical anion of the previously reported tetraphenyl DCF, coupling to the four phenyl rings is strongly attenuated. The data provide physical evidence for the different conjugation between the DCF core and the substituents in both systems. We also report the preparation of new fulvene-based push-pull chromophores via formal [2+2] cycloaddition-retroelectrocyclization reaction of DCFs with electron-rich alkynes. Alkynylated and phenylated DCFs show opposite regioselectivity of the cycloaddition, which can be explained by the differences in electronic communication between substituents and the DCF core as revealed in the EPR spectra of the radical anions.
Authors:
Aaron D Finke; Oliver Dumele; Michal Zalibera; Daria Confortin; Pawel Cias; Govindasamy Jayamurugan; Jean-Paul Gisselbrecht; Corinne Boudon; W Bernd Schweizer; Georg Gescheidt; Francois Diederich
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Publication Detail:
Type:  JOURNAL ARTICLE     Date:  2012-10-8
Journal Detail:
Title:  Journal of the American Chemical Society     Volume:  -     ISSN:  1520-5126     ISO Abbreviation:  J. Am. Chem. Soc.     Publication Date:  2012 Oct 
Date Detail:
Created Date:  2012-10-9     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  7503056     Medline TA:  J Am Chem Soc     Country:  -    
Other Details:
Languages:  ENG     Pagination:  -     Citation Subset:  -    
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