The preparation and absolute configurations of enantiomerically pure C4-symmetric tetraalkoxyresorcin[4]arenes obtained from camphorsulfonate derivatives

Benjamin R. Buckley, Philip C. Bulman Page, Yohan Chan, Harry Heaney, Michael Klaes, Matthew J. McIldowie, Vickie McKee, Jochen Mattay, Mauro Mocerino, Eduardo Moreno, Brian W. Skelton, Allan H. White

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Abstract

The preparation of a series of diastereoisomeric tetracamphorsulfonates derived from racemic tetramethoxyresorcin[4]arenes was achieved by reactions with an excess of (S)(+)-10-camphorsulfonyl chloride in pyridine followed by isolation using flash chromatography. Tetradeprotonation of a number of tetramethoxyresorcin[4]arenes using n-butyllithium in tetrahydrofuran, followed by reactions using (S)-(+)10-camphorsulfonyl chloride, gave the same tetracamphorsulfonates. Mono-, di- and tricamphorsulfonates were also prepared following selective deprotonation. In the reactions with tetraisopropyloxy- and tetracyclopentyloxyresorcin[4]arenes, only the mono- and dicamphorsulfonates were formed. X-ray crystallographic analysis established the absolute configurations of three diastereoisomerically pure tetracamphorsulfonates, including a diastereoisomer prepared from 6,12,18,24-tetramethoxy-2,8,14,20-tetrakis(2-methylpropyl)resorcin[4]are ne. An additional pair of diastereoisomers was also prepared using (R)-(-)-10-camphorsulfonyl chloride and 6,12,18,24-tetramethoxy-2,8,14,20-tetrakis(2-methylpropyl)resorcin[4]are ne, for one of which the structure was confirmed by an additional X-ray structure determination. Hydrolytic removal of the camphorsulfonyl residue(s) from the various diastereoisomers gave enantiomers of known absolute configurations. In some cases, the chiral nonracemic tetraalkoxyresorcin[4]arenes were converted into known tetrabenzoxazine derivatives by using N,N-bis(methoxymethyl)[(S)-(-)-(a-methylbenzyl)]amine in thermal or microwave - assisted reactions. (c) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006.
Original languageEnglish
Pages (from-to)5135-5151
JournalEuropean Journal of Organic Chemistry
Volume2006
Issue number22
DOIs
Publication statusPublished - 13 Nov 2006

Keywords

  • MITTEILUNG
  • ACID
  • RESORCINARENES
  • CYCLODIASTEREOMERIE
  • diastereoselectivity
  • CHIRALITY
  • CALIXARENES
  • camphorsulfonates
  • determination
  • hydrolysis
  • chiral auxiliaries
  • BINAPHTHYL CROWN UNIT
  • OPTICAL RESOLUTION
  • CALIX<4>ARENES
  • axial chirality
  • CYCLOENANTIOMERIE
  • Mannich reactions
  • configuration
  • resorcin[4]arenes

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