Structure of the naphthylurethane of trans-β-ionol, a severely nonplanar 1,3-diene

Abstract

4-(2,6,6-Trimethyl-1-cyclohexen-1-yl)-3-buten-2-yl 1-naphthalenecarbamate, the 1-naphthylurethane of trans-β-ionol, possesses a 1,3-diene π system which is grossly nonplanar as a consequence of sterically enforced torsion about the central single bond, the torsion angle between the formal double bonds being 54 o . This result is in excellent agreement with conclusions concerning the «nonvertical» behaviour of the parent trans-β-ionol with respect to triplet-excitation transfer