Stereoselective synthesis of all stereoisomers of vicinal and distal bis(O-2-aminoethyl)-p-tert-butylthiacalix[4]arene

O,O"- and O,O'-bis(2-aminoethyl)-p-tert-butylthiacalix[4]arenes of anti conformation have been prepared by the reduction of the corresponding O,O"- and O,O'-bis(cyanomethyl) ethers. Their syn-O,O"- and O,O'-counterparts have been prepared by alternative routes via the Mitsunobu reaction of thiacalix[4]arene with N-(2-hydroxyethyl)phthalimide and the reduction of a O,O'-disiloxanediyl-bridged O",O"'-bis(cyanomethyl) ether of 1,2-alternate conformation, respectively. These products are expected to serve as useful precursors of highly elaborated synthetic receptors, including biscalixarenes. (C) 2004 Elsevier Ltd. All rights reserved.