Stereoselective dialkylation of the proximal hydroxy groups of calix- And thiacalix[4]arenes

Fumitaka Narumi, Tetsutaro Hattori, Naoya Morohashi, Nobuji Matsumura, Waka Yamabuki, Hiroshi Kameyama, Sotaro Miyano

Research output: Contribution to journalArticle

18 Citations (Scopus)

Abstract

Treatment of p-tert-butylcalix[4]arene (C1) and its sulfur-bridged analog T1 with 1,3-dichloro-1,1,3,3-tetraiso-propyldisiloxane in the presence of imidazole gives proximally O,O′-disiloxane-1,3-diyl-bridged calixarenes C2 and T2 in excellent yields, respectively. Subsequent base-catalyzed etherification of the remaining hydroxy groups with alkyl halides gives syn- and anti-O″,O‴-dialkylated products, the stereoselectivity of which varies depending on the nature of the macrocycle, as well as the metal cation of the base employed. Thus, conventional calixarene C2 preferentially affords syn compounds of 1,2-alternate conformation (C3) with the aid of tert-BuOK and K2CO3 and anti counterparts of partial-cone conformation (C4) with Cs2CO3. On the other hand, thiacalixarene T2 affords syn compounds of 1,2-alternate conformation (T3) with any of the bases. The disiloxanediyl bridge of the resulting products can readily be removed by treatment with tetrabutylammonium fluoride. Thus, the net process provides an efficient method for the regio- and stereoselective synthesis of proximally dialkylated calix[4]arenes.

Original languageEnglish
Pages (from-to)890-898
Number of pages9
JournalOrganic and Biomolecular Chemistry
Volume2
Issue number6
DOIs
Publication statusPublished - 2004 Mar 21

ASJC Scopus subject areas

  • Biochemistry
  • Physical and Theoretical Chemistry
  • Organic Chemistry

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