Intramolecular [2+2+2] cycloaddition of bis(propargylphenyl)carbodiimides: synthesis of L-shaped π-extended compounds with pyrrolo[1,2-a][1,8]naphthyridine corner units

摘要

L-shaped π-extended penta-, hexa-, and heptacycles with a pyrrolo-[1,2-a][1,8]naphthyridine junction were prepared from N,N'-bis-[2-(2-alkyn-1-yl)phenyl]carbodiimides or their naphthyl analogs via Rh(Ⅰ)-catalyzed intramolecular [2+2+2] cycloaddition and dehydro-genative aromatization. These L-shaped compounds emit sky-blue, yellow-green, or golden-orange fluorescence, with high quantum yields.