SELECTIVE FUNCTIONALIZATION OF CALIX[6]ARENES AT THE UPPER RIM

Methylation of partially O-benzylated p-tert-butylcalix[6]arenes follo wed by hydrogenolysis constitutes an efficient method for the preparat ion of partially O-alkylated calix[6]arenes in gram amounts, without a dhering to column chromatography separations. Selective de-tert-butyla tion followed by halogenation, or ipso-nitration of these precursors a ffords calix[6]arenes containing bromo- or nitrosubstituents, respecti vely, at precise positions of the upper rim.