| Abstract
| - meso-Tetrakis(2-pyridyl)-porphyrin (2-PyP) was tetra-N-alkylated with three different α-bromoacetamides to generatea series of water-soluble N-alkylpyridinium porphyrins(1−3). The product mixtures showed a marked preferencefor the formation of the ααββ atropisomer. With α-bromo-N-n-butylacetamide, the corresponding ααββ 2-tetrakis (N-n-butylacetamido)-pyridyl porphyrin (2-TnBuPyP, 3) wasobtained in 69% isolated yield in a single step. Prolongedheating lead to equilibration of the rotational isomers for theless bulky alkyl groups, indicating that the observed preference is a kinetic effect. The intermediate products for theN-bornyl case were identified by LC/ESI-MS to deduce anexplanation for the observed nonstatistical selectivity.
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