A Naphtho-Fused Double [7]Helicene from a Maleate-Bridged Chrysene Trimer.
Perkin condensation of chrysenyl-6-acetic acid with chrysenylene-6,12-diglyoxylic acid followed by in situ esterification gives a bismaleate, whose conjugated stilbene moieties are efficiently shielded against intermolecular condensations and undergo iodine-catalyzed oxidative photocyclization in toluene without the need for high dilution. The concentration is limited by the low solubility of the flexible bismaleate at room temperature. The so-obtained double [7]helicene crystallizes in a nonchiral meso form. It is notably more soluble than its flexible precursor because it cannot fold to optimize π-π stacking.
Centre de Recherche Paul Pascal, CNRS, 115, av. Schweitzer, 33600, Pessac, France.|Departamento de Química, Universidade Federal de Santa Catarina, CEP, 88040-900, Florianópolis, Santa Catarina, Brazil.
Marli
M
Ferreira
Centre de Recherche Paul Pascal, Université de Bordeaux, 115, av. Schweitzer, 33600, Pessac, France.
Guillaume
G
Naulet
Departamento de Química, Universidade Federal de Santa Catarina, CEP, 88040-900, Florianópolis, Santa Catarina, Brazil.
Hugo
H
Gallardo
Centre de Recherche Paul Pascal, Université de Bordeaux, 115, av. Schweitzer, 33600, Pessac, France.
Pierre
P
Dechambenoit
Centre de Recherche Paul Pascal, CNRS, 115, av. Schweitzer, 33600, Pessac, France.
Harald
0000-0002-0479-8203
H
Bock
Centre de Recherche Paul Pascal, CNRS, 115, av. Schweitzer, 33600, Pessac, France.
Fabien
F
Durola
dehydrogenation; fused-ring systems; helical structures; photooxidation; strained molecules