A Three-Step Synthetic Approach to Asymmetrically Functionalized 4H-Cyclopenta[2,1-b:3,4-b ']dithiophenes

Sarah Van Mierloo, Peter J. Adriaensens, Wouter Maes, Laurence Lutsen, Thomas J. Cleij, Edith Botek, Benoit Champagne, Dirk J. M. Vanderzande*

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

21 Citations (Web of Science)

Abstract

A convenient and efficient three-step route toward both symmetrically and asymmetrically functionalized 4H-cyclopenta[2,1-b:3,4-b']dithiophenes has been developed. Using this method a broad collection of functionalized bridged bithiophenes can smoothly be accessed. Starting from 3-bromo-2,2'-bithiophene, prepared by Kumada coupling of 2-thienylmagnesium bromide with 2,3-dibromothiophene under Pd(dppf)Cl(2) catalysis, lithiation and subsequent reaction with dialkyl ketones afforded (a)symmetrically dialkylated tertiary alcohol derivatives. By means of final Friedel-Crafts dehydration cyclization in sulfuric acid medium, these derivatives were converted to 4,4-dialkyl-4H-cyclopenta[2,1-b:3,4-b']dithiophenes. Upon replacement of the dialkyl ketone reagent by ethyl levulinate, an ester-functionalized 4H-cyclopenta[2,1-b:3,4-b']dithiophene was prepared, representing an attractive precursor for variously functionalized cyclopentadithiophene compounds.
Original languageEnglish
Pages (from-to)7202-7209
JournalJournal of Organic Chemistry
Volume75
Issue number21
DOIs
Publication statusPublished - 5 Nov 2010
Externally publishedYes

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