Acid-promoted rearrangement of carbonate functionality anchored to the lower rim of a Calix
A unique calix[4]arene lower-rim intramolecular rearrangement, resulting in molecular asymmetry arising from the upper- and lower-rim substitution pattern, produces a new class of inherently chiral calix[4]arenes in a partial cone conformation. This was aided by molecular rigidification arising from pi-pi and C-H.pi interactions between bulky lower-rim substituents, with the corresponding circular dichroism spectra exhibiting the most intense bisignate Cotton effects yet observed for calix[4]arenes not bearing a chiral center.
Inoue Photochirogenesis Project, ERATO, JST, 4-6-3 Kamishinden, Osaka 565-0085, Japan, Department of Chemistry, The University of Reading, Whiteknights, Reading, RG6 6AD, U.K., and Department of Chemistry, Oxford University, South Parks Road.
D
Hesek
Y
Inoue
MG
Drew
PD
Beer
GA
Hembury
H
Ishida
F
Aoki