Benzimidazoles and quinoxalines are important N-heteroaromatics with many applications in pharmaceutical and chemical industry. Here, the synthesis of both classes of compounds starting from aromatic diamines and alcohols (benzimidazoles) or diols (quinoxalines) is reported. The reactions proceed through acceptorless dehydrogenative condensation steps. Water and two equivalents of hydrogen are liberated in the course of the reactions. An Ir complex stabilized by the tridentate P^N^P ligand N(2) ,N(6) -bis(di-isopropylphosphino)pyridine-2,6-diamine revealed the highest catalytic activity for both reactions.

An iridium catalyst -stabilized by an anionic P,N ligand -was used for the symmetrical and unsymmetrical monoalkylation of para-, meta-, and ortho-benzenediamines. Benzyl and aliphatic alcohols were used as alkylating reagents. 28 derivatives were synthesized. 14 of them are new compounds. Furthermore, the alkylation of the pharma-cological important diamine Dapson (dapsone) is described. 14 dapsone derivatives were synthesized among them 9 new compounds.

New reactions that convert alcohols into important classes of compounds are becoming increasingly important as their development contributes to the conservation of our fossil carbon feedstock and the reduction of CO emissions. Two key catalytic alcohol conversion concepts are borrowing hydrogen or hydrogen autotransfer and acceptorless dehydrogenative condensation. Herein, we combined both concepts to synthesize meta-functionalized pyridines. First, diols and amines were linked to β-amino alcohols, which can then undergo a selective dehydrogenative heterocondensation with γ-amino alcohols. Iridium catalysts stabilized by PN P pincer ligands that were developed in our laboratory mediate the reactions most efficiently. All of the 3-aminopyridines that we describe in this paper have been synthesized for the first time, emphasizing the degree of innovation of this method and the problems associated with the synthesis of such meta-functionalized pyridines.

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The synthesis of benzimidazoles starting from aromatic diamines and alcohols is reported.

Benzene‐1,4‐, 1,3,‐ and 1,2‐diamines and antibiotic diamine dapsone (Id) are transformed to the title diamines by reaction with benzylic or aliphatic alcohols.