Diatropicity of dehydrobenzo[14]annulenes: comparative analysis of the bond-fixing ability of benzene on the parent 3,4,7,8,9,10,13,14-octadehydro[14]annulene.

[structure: see text]. We report the synthesis of 3,4,7,8,9,10,13,14-octadehydro[14]annulene (1) and detail a comparative aromaticity study with its benzannelated derivatives (e.g., 2 and 3).

Dehydrobenzoannulene-dimethyl-dihydropyrene hybrids: model systems for the synthesis of molecular aromatic probes.

Synthesis of two novel dehydrobenzoannulene-dimethyldihydropyrene (DBA-DDP) hybrids has been achieved using a Pd/Cu cross-coupling strategy.

Carbon networks based on dehydrobenzoannulenes. 4. Synthesis of "star" and "trefoil" graphdiyne substructures via sixfold cross-coupling of hexaiodobenzene.

The synthesis and characterization of star- and trefoil-shaped polyethynyl aromatic structures, which represent model substructures of the all-carbon network graphdiyne, are described. Assembly of these macrocycles is accomplished via 6-fold Sonogashira cross-coupling of hexaiodobenzene using Pd[P(o-Tol)(3)](2) and CuI as the catalytic system. The development of these modified Sonogashira conditions is detailed. This work has led to the synthesis of a new family of hexakis(phenylbutadiynyl)benzene derivatives (4a-c), the largest of which is the D(3)(h)()-symmetric "trefoil" 2 and is composed of three [18]annulenes fused at a common benzene ring. Attempts at the synthesis of "wheel" 3 are also described. Compound 2 represents the largest fragment of the graphdiyne network to date. UV-vis spectroscopic studies indicate enhanced electron delocalization throughout the extended pi-system.

[2.2]paracyclophane/dehydrobenzoannulene hybrids: transannular delocalization in open-circuited conjugated macrocycles.

Enhanced global delocalization throughout the "stepped" π-electron systems of the [2.2]paracyclophane/dehydrobenzoannulene (PC/DBA) hybrids 1 and 2 is strongly suggested by a comparison of their electronic absorption spectra with those of model compounds with complete and interrupted classical aromatic delocalization. A distinct bathochromic shift (for 1) and greater absorption intensity at higher wavelengths (for 1 and 2) is observed versus the corresponding model hydrocarbons.