selectivity of up to 92%. The role of the NH motive was underlined during this work.
Methylation of the nitrogen blocked this position for MLC reactions, which almost
shuttled down the catalytic activity of the used system.
4 Conclusion
Sustainable (de)hydrogenation reactions employing well-defined manganese complexes became an important and fast-growing field within the last few years. The fact
that most of the catalysts are air- and moisture-stable enables easy access to a wide
range of researchers beyond specialized experts. Apart from the high stability of
many manganese(I)-based systems, the broad applicability in hydrogenation and
dehydrogenation in conjunction with subsequent condensation reactions renders
these catalysts powerful players in the field of homogeneous catalysis. So far, a
large majority of manganese-based catalysts rely strongly on metal-ligand cooperation involving as yet mostly pincer and pincer-type complexes. This approach
showed remarkable reactivity for several applications but also revealed limitations,
especially for the functionalization of unpolarized functional groups such as C-C
Scheme 48 Alkylation of sulfonamides catalyzed by Mn14 and Mn9
Scheme 49 Upgrading of ethanol employing the Guerbet reaction mediated by Mn1
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S. Weber and K. Kirchner