A 3-fold stereoselective cyclocondensation of the azomethines 3 and 11 yields the [18]annulenes 4 and 12, respectively. The [abc]-annelation of naphthalene or phenanthrene systems realized here for the first time, leads to nonplanar molecules consisting of 'aromatic islands", which are connected by (E)-configured olefinic bridges. The absence of a diamagnetic ring current rules out a macrocyclic aromaticity. The NMR investigation, based on selective deuterations, is sustained by force field calculations (MMX). The disc-like compounds represent discotic mesogens of an enormous diameter. The formation of thermotropic liquid crystals can be achieved by the introduction of long flexible alkoxy chains.
A 3-fold stereoselective cyclocondensation of the azomethines 3 and 11 yields the [18]annulenes 4 and 12, respectively. The [abc]-annelation of naphthalene or phenanthrene systems realized here for the first time, leads to nonplanar molecules consisting of 'aromatic islands", which are connected by (E)-configured olefinic bridges. The absence of a diamagnetic ring current rules out a macrocyclic aromaticity. The NMR investigation, based on selective deuterations, is sustained by force field calculations (MMX). The disc-like compounds represent discotic mesogens of an enormous diameter. The formation of thermotropic liquid crystals can be achieved by the introduction of long flexible alkoxy chains.
A 3-fold stereoselective cyclocondensation of the azomethines 3 and 11 yields the [18]annulenes 4 and 12, respectively. The [abc]-annelation of naphthalene or phenanthrene systems realized here for the first time, leads to nonplanar molecules consisting of 'aromatic islands", which are connected by (E)-configured olefinic bridges. The absence of a diamagnetic ring current rules out a macrocyclic aromaticity. The NMR investigation, based on selective deuterations, is sustained by force field calculations (MMX). The disc-like compounds represent discotic mesogens of an enormous diameter. The formation of thermotropic liquid crystals can be achieved by the introduction of long flexible alkoxy chains.