Borrowing hydrogen (or hydrogen autotransfer) reactions represent straightforward and sustainable C–N bond-forming processes. In general, precious metal-based catalysts are employed for this effective transformation. In recent years, the use of earth abundant and cheap non-noble metal catalysts for this process attracted considerable attention in the scientific community. Here we show that the selective N-alkylation of amines with alcohols can be catalysed by defined PNP manganese pincer complexes. A variety of substituted anilines are monoalkylated with different (hetero)aromatic and aliphatic alcohols even in the presence of other sensitive reducible functional groups. As a special highlight, we report the chemoselective monomethylation of primary amines using methanol under mild conditions.

Pincer complexes are becoming increasingly important for organometallic chemistry and organic synthesis. Since numerous applications for such catalysts have been developed in recent decades, this Minireview covers progress in their use as catalysts for (de)hydrogenation and transfer (de)hydrogenation reactions during the last four years. Aside from noble-metal-based pincer complexes, the corresponding base metal complexes are also highlighted and their applications summarized.

A novel lutidine-based manganese PNP-pincer complex has been synthesized for the selective N-methylation of aromatic amines with methanol. Using borrowing hydrogen methodology, a selection of differently functionalized aniline derivatives is selectively methylated in good yields.

Selective catalytic reductions of nitriles are presented using the commercially available Ru‐Macho‐BH complex. A variety of aliphatic, aromatic and (hetero)cyclic nitriles including industrially important adipodinitrile are hydrogenated to the corresponding primary amines. Modelling suggests the reaction follows an outer sphere hydrogenation mechanism.

Review: [128 refs.

A manganese PNP‐pincer complex was developed as a suitable catalyst for the selective mono‐methylation of aromatic amines with inexpensive methanol. Using borrowing hydrogen methodology, a selection of different aniline derivatives was selectively methylated, tolerating functional groups such as ketone, C=C double bonds, or amides. The novel manganese PNP‐pincer complex allowed for methylations under mild conditions in high yields. More information can be found in the Communication by M. Beller, et al. on page 5410 ff.

This developed protocol for the efficient Ru‐catalyzed reduction of nitriles allows the conversion of aliphatic, aromatic, and heteroaromatic into the corresponding amines.