Unexpected formation of disulfide-based biscalix[4]arenes. Issue 5 (4th February 2016)

• Record Type: Journal Article
• Authors: Stejskal, František; Cuřínová, Petra; Lhoták, Pavel
• Is Part Of: Tetrahedron. Volume 72:Issue 5(2016)
• Page Start: 760
• Page End: 766
• Publication Date: 2016-02-04
• Subjects: Calixarene -- Bridging reaction -- Dimer formation -- Complexation -- Cation-π interactions -- Pyridinium guests; Chemistry, Organic -- Periodicals; 547.005
• DOI: 10.1016/j.tet.2015.12.037
• Languages: English
• ISSNs: 0040-4020

Abstract

Abstract: Attempts at Pd-catalyzed bridging in sulfoxide-bearing calixarenes containing various substituents (phenyl, ethyl, pyrimidin-2-yl) gave the expected compound only in the case of the ethyl derivative. However, the reaction of sulfoxides with BuLi revealed the ability of the pyrimidin-2-yl group to function unexpectedly as a leaving group. This enabled, depending on the reaction conditions, preparation of unique bis-calixarenes connected together via two sulfur atoms spacers: –S–S–, –S(O)–S– or –S(O)2 –S–. As documented by 1 H NMR titrations these compounds, otherwise not easily accessible by common synthetic methods, showed recognition ability towards selected cations of the N -methylpyridinium type. Graphical abstract: