Regioselective O-alkylations and acylations of polyphenolic substrates using a calix[4]pyrrole derivative

The 10α,20α-bis(4-nitrophenyl)-calix[4]pyrrole 2 can act as a topologically selective protecting group in the O-alkylation and acylation of polyphenolic polycyclic aromatic compounds thanks to the regioselective formation of phenolate-type complexes. Remarkably, the host–guest interaction with the anionic reagents is sufficiently strong and kinetically slow to produce a high degree of selectivity.