Palladium-Catalyzed Annulative π-Extension of Bay-Iodinated Triphenylenes to Access Polycyclic Aromatic Compounds.

A palladium-catalyzed annulative π-extension reaction of bay-iodinated triphenylenes with aryl iodides/o-chloroaromatic carboxylic acids was developed. This approach enabled the synthesis of diverse polycyclic aromatic compounds, including dibenzo[fg,op]tetracenes, azadibenzo[fg,op]tetracenes, and tribenzo[a,g,m]coronenes. Initial studies indicate that the resulting product, 2,3,8,9,14,15-hexakis(decyloxy)tribenzo[a,g,m]coronene, exhibits good liquid-crystalline properties.

Electron Paramagnetic Resonance Tracks Condition-Sensitive Water Radical Cation.

Oxidizing species or radicals generated in water are of vital importance in catalysis, the environment, and biology. In addition to several related reactive oxygen species, using electron paramagnetic resonance (EPR), we present a nontrapping chemical transformation pathway to track water radical cation (H2O+•) species, whose formation is very sensitive to the conditioning environments, such as light irradiation, mechanical action, and gas/chemical introduction. We reveal that H2O+• can oxidize the 5,5-dimethyl-1-pyrroline N-oxide (DMPO) to the crucial epoxy hydroxylamine (HDMP=O) intermediate, which further reacts with the hydroxyl radical (•OH) for the formation of the EPR-active sextet radical (DMPO=O•). Interestingly, we uncover that H2O+• can react with dimethyl methylphosphonate (DMMP), 2-methyl-2-nitrosopropane (MNP), 5-tert-butoxycarbonyl-5-methyl-1-pyrroline N-oxide (BMPO), and α-phenyl-N-tert-butylnitrone (PBN) which contain a double-bond structure to produce corresponding derivatives as well. It is thus expected that both H2O+• and •OH are ubiquitous in nature and in various water-containing experimental systems. These findings provide a novel perspective on radicals for water redox chemistry.

Palladium-catalyzed annulative π-extension of o-halobiphenyls with o-chloropyridinecarboxylic acids to access azatriphenylenes.

A palladium-catalyzed bay-region annulative π-extension reaction of o-halobiphenyls with o-chloropyridinecarboxylic acids was developed. The reaction was carried out with a 1 : 1 ratio of substrates. A variety of azatriphenylene derivatives could be synthesized by this approach. This transformation could be applied to the synthesis of ionic liquid-crystalline molecules.

Bay-Region Annulative π-Extension of o-Iodobiphenyls with Aliphatic Anhydrides Catalyzed by Pd(OAc)2.

Bay-region annulative π-extension of o-iodobiphenyls with aliphatic anhydrides was developed. Many o-iodobiphenyls and aliphatic anhydrides can react well under the optimized conditions. A lot of phenanthrol derivatives can be efficiently prepared by this approach. The control experiments support that dibenzopalladacyclopentadienes may be the reaction intermediates.

Synthesis of Tribenzo[b,d,f]azepines via Palladium-Catalyzed Annulation Reaction of 2-Iodobiphenyls with 2-Halogenoanilines.

A palladium-catalyzed annulation reaction of 2-iodobiphenyls with 2-halogenoanilines has been developed. A variety of 2-iodobiphenyls and 2-halogenoanilines can undergo this transformation. Diversified tribenzo[b,d,f]azepine derivatives can be synthesized in moderate to excellent yields according to this method.

Regiodivergent C-H Arylation of Triphenylene Derivatives Controlled by Electronic Effects of Diaryliodonium Salts.

A regiodivergent C-H arylation of triphenylene derivatives with diaryliodonium salts was developed. The regiodivergence was controlled by electronic effects of diaryliodonium salts. When the aryl(mesityl)iodonium salts bearing strong electron-donating groups at the para-position of aryl groups were used, the arylation reactions occurred ortho to amide groups. However, if the aryl(mesityl)iodonium salts bearing electron-withdrawing groups or weak electron-donating groups at the para-position of aryl groups were utilized, the arylation reactions occurred meta to amide groups.

Construction of Unsymmetrical Triphenylenes from Electron-Rich Biphenyls and Diaryliodonium Salts via Copper-Catalyzed Multiple C-H Arylation.

An efficient protocol to synthesize unsymmetrical triphenylenes from electron-rich biphenyls and diaryliodonium salts via Cu catalysis was developed. A variety of unsymmetrical triphenylenes with diversified functional groups were synthesized according to this method. This transformation went through multiple direct C-H arylations from easily produced starting materials with high step-economy. The gram-scale synthesis of triphenylenes and their facile transformation into diverse functional organic molecules were illustrated.

Copper-Catalyzed Regioselective C-H Sulfonyloxylation of Electron-Rich Arenes with p-Toluenesulfonic Acid and Sulfonyloxylation of Aryl(mesityl)iodonium Sulfonates.

Copper-catalyzed regioselective C-H sulfonyloxylation of electron-rich arenes with p-toluenesulfonic acid has been developed. Electron-rich benzene derivatives and heteroarenes can undergo this C-H sulfonyloxylation reaction to generate aryl tosylates. Furthermore, sulfonyloxylation of aryl(mesityl)iodonium sulfonates has also been investigated. Both aryl(mesityl)iodonium tosylates and triflates can react smoothly to get aryl sulfonates. The formed aryl sulfonates can be converted to phenols, as well as used as good partners of cross-coupling reactions.

A convenient tandem one-pot synthesis of donor-acceptor-type triphenylene 2,3-dicarboxylic esters from diarylacetylene.

A tandem one-pot method for the direct synthesis of polysubstituted triphenylene 2,3-dicarboxylic esters with different substitution patterns was developed by enyne metathesis of diarylacetylene, followed by Diels-Alder, aromatization and a cyclization cascade.

Synthesis of benzimidazoles by potassium tert-butoxide-promoted intermolecular cyclization reaction of 2-iodoanilines with nitriles.

The synthesis of benzimidazoles by intermolecular cyclization reaction of 2-iodoanilines with nitriles has been developed. These reactions proceeded without the aid of any transition metals or ligands and just using KOBu(t) as the base. A variety of substituted benzimidazole derivatives can be synthesized by the approach.

Organocatalytic asymmetric intermolecular dehydrogenative α-alkylation of aldehydes using molecular oxygen as oxidant.

An organocatalytic enantioselective intermolecular oxidative dehydrogenative α-alkylation of aldehydes via benzylic C-H bond activation has been developed. The asymmetric reaction is smoothly fulfilled by using simple and green molecular oxygen as the oxidant. Two hydrogen dissociations make this transformation more environmentally benign because of high atom efficiency.

Morpholine catalyzed direct C3 alkenylation of indoles with α,ß-unsaturated aldehydes.

Organocatalytic direct C3 alkenylation of indoles has been developed. Simple and readily available morpholine trifluoroacetic acid salt is employed as an efficient catalyst in this oxidative dehydrogenative reaction. Simplicity and practicality constitute the most attractive advantages of this reaction.

The versatile roles of ammonium salt catalysts in enantioselective reduction and alkylation of α,ß-unsaturated aldehydes: iminium catalysis, enamine catalysis and acid catalysis.

A novel strategy for highly efficient utilization of chiral ammonium salt catalysts has been described in this paper. Three kinds of catalytic functions including iminium catalysis, enamine catalysis, and acid catalysis of chiral ammonium salt catalysts, have been achieved in the enantioselective reduction and alkylation reaction of α,ß-unsaturated aldehydes with alcohols.

Sp-sp(3) C-C bond formation via Fe(OTf)(3)/TfOH cocatalyzed coupling reaction of terminal alkynes with benzylic alcohols.

An Fe(OTf)(3)/TfOH cocatalyzed sp-sp(3) C-C bond formation through the coupling of benzylic alcohols with terminal alkynes in the absence of base has been developed. H(2)O is the sole by-product.

Methylation of arenes via Ni-catalyzed aryl C-O/F activation.

Aryl C-O and C-F can be transformed into C-Me via Ni-catalyzed coupling with MeMgBr under mild conditions.