Further Observations on Conformational and Substituent Effects in Acid-Catalyzed “3 + 1” Cyclizations of Tripyrranes with Aromatic Dialdehydes
作者:Timothy D. Lash、Katrina M. Bergman
DOI:10.1021/jo301945f
日期:2012.11.2
Tripyrranes with tert-butyl and phenyl substituents have been prepared and used to synthesize oxybenziporphyrins, oxypyriporphyrins, benzocarbaporphyrins, and azuliporphyrins with phenyl and tert-butyl substituents via a “3 + 1” methodology. The proton NMR spectra for the tripyrrane dibenzyl esters indicate that these tripyrrolic systems take on a helical conformation that favors macrocycle formation