A new synthetic strategy for the construction of an inherently chiral, sulfur-bridged calixarene molecular framework was presented by oxidation of one of the four epithio bonds of a tetrathiacalixarene derivative of 1,3-alternate conformation: Tetra(carboxymethyl) ether of p-tert-butyltetrathiacalixarene of 1,3-alternate conformation (7) was converted to the tetra(l-menthoxycarbonylmethyl) ether (8). Oxidation of the tetra l-menthyl ester 8 by treatment with NaBO3 (1.1 molar equiv.) afforded a pair of diastereomers of the monosulfinyl derivatives (9) in 58% yield, which were readily separable by silica-gel column chromatography. Removal of the l-menthyl moieties followed by methyl esterification gave enantiomerically pure samples of inherently chiral (-)- and (+)-monosulfmyltrithiacalixarene derivatives ((-)-10 and (+)-10) in 62 and 56% yield, respectively.
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