Manganese-Catalyzed Dehydrogenative Silylation of Alkenes Following Two Parallel Inner-Sphere Pathways

Weber, Stefan; Glavic, Manuel; Stöger, Berthold; Pittenauer, Ernst; Podewitz, Maren; Veiros, Luı́s F.; Kirchner, Karl

doi:10.1021/jacs.1c09175

Cited by 35 publications

(23 citation statements)

References 49 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In the same year, Kirchner developed the same methodology with their PP-chelated Mn( i )-alkyl-complex Mn16 (Table 41, entry 3). 501 The catalyst was activated via similar alkyl migration as that discussed in previous sections. However, the method developed was not totally acceptorless.…”

Section: Manganese-catalyzed Hydroelementation Reactionsmentioning

confidence: 99%

Manganese-catalyzed hydrogenation, dehydrogenation, and hydroelementation reactions

et al. 2022

View full text Add to dashboard Cite

show abstract

Section: Manganese-catalyzed Hydroelementation Reactionsmentioning

confidence: 99%

Manganese-catalyzed hydrogenation, dehydrogenation, and hydroelementation reactions

et al. 2022

View full text Add to dashboard Cite

show abstract

“… 2021 143 17825 17832 . 3 Highly E-selective dehydrogenative silylation of monosubstituted alkenes at mild reaction condition was disclosed. Mechanistic investigations revealed the presence of two parallel pathways—one requiring an alkene substrate as the sacrificial agent and one being acceptorless involving dihydrogen formation .…”

Section: Key Referencesmentioning

confidence: 99%

Manganese Alkyl Carbonyl Complexes: From Iconic Stoichiometric Textbook Reactions to Catalytic Applications

Weber¹,

Kirchner²

2022

Acc. Chem. Res.

Self Cite

View full text Add to dashboard Cite

Conspectus The activation of weakly polarized bonds represents a challenging, yet highly valuable process. In this context, precious metal catalysts have been used as reliable compounds for the activation of rather inert bonds for the last several decades. Nevertheless, base-metal complexes including cobalt, iron, or nickel are currently promising candidates for the substitution of noble metals in order to develop more sustainable processes. In the past few years, manganese(I)-based complexes were heavily employed as efficient catalysts for (de)hydrogenation reactions. However, the vast majority of these complexes operate via a metal–ligand bifunctionality as already well implemented for precious metals decades ago. Although high reactivity can be achieved in various reactions, this concept is often not applicable to certain transformations due to outer-sphere mechanisms. In this Account, we outline the potential of alkylated Mn(I)-carbonyl complexes for the activation of nonpolar and moderately polar E–H (E = H, B, C, Si) bonds and disclose our successful approach for the utilization of complexes in the field of homogeneous catalysis. This involves the rational design of manganese complexes for hydrogenation reactions involving ketones, nitriles, carbon dioxide, and alkynes. In addition to that, the reduction of alkenes by dihydrogen could be achieved by a series of well-defined manganese complexes which was not possible before. Furthermore, we elucidate the potential of our Mn-based catalysts in the field of hydrofunctionalization reactions for carbon–carbon multiple bonds. Our investigations unveiled novel insights into reaction pathways of dehydrogenative silylation of alkenes and trans -1,2-diboration of terminal alkynes, which was not yet reported for transition metals. Due to rational catalyst design, these transformations can be achieved under mild reaction conditions. Delightfully, all of the employed complexes are bench-stable compounds. We took advantage of the fact that Mn(I) alkyl complexes are known to undergo migratory insertion of the alkyl group into the CO ligand, yielding an unsaturated acyl intermediate. Hydrogen atom abstraction by the acyl ligand then paves the way to an active species for a variety of catalytic transformations which all proceed via an inner-sphere process. Although these textbook reactions have been well-known for decades, the application in catalytic transformations is still in its infancy. A brief historical overview of alkylated manganese(I)–carbonyl complexes is provided, covering the synthesis and especially iconic stoichiometric transformations, e.g., carbonylation, as intensively examined by Calderazzo, Moss, and others. An outline of potential future applications of defined alkyl manganese complexes will be given, which may inspire researchers for the development of novel (base-)metal catalysts.

show abstract

“…We have recently reported on the application of the Mn(I) alkyl complex fac -[Mn(dippe)(CO) 3 (CH 2 CH 2 CH 3 )] (dippe = 1,2-bis(di- iso -propylphosphino)ethane) ( Mn1 ) as precatalyst for the hydrogenation of ketones, 22 nitriles, 23 alkenes, 24 CO 2 , 25 the hydroboration and diboration of alkenes and alkynes, 26 the dehydrogenative silylation of alkenes, 27 and the dimerization and cross-coupling of terminal alkynes. 28 Inspired by these results, we wondered if Mn1 is also active in the semihydrogenation of alkynes.…”

Section: Introductionmentioning

confidence: 99%

E-Selective Manganese-Catalyzed Semihydrogenation of Alkynes with H₂ Directly Employed or In Situ-Generated

et al. 2022

Self Cite

View full text Add to dashboard Cite

Selective semihydrogenation of alkynes with the Mn(I) alkyl catalyst fac -[Mn(dippe)(CO) 3 (CH 2 CH 2 CH 3 )] (dippe = 1,2-bis(di- iso -propylphosphino)ethane) as a precatalyst is described. The required hydrogen gas is either directly employed or in situ-generated upon alcoholysis of KBH 4 with methanol. A series of aryl-aryl, aryl-alkyl, alkyl-alkyl, and terminal alkynes was readily hydrogenated to yield E- alkenes in good to excellent isolated yields. The reaction proceeds at 60 °C for directly employed hydrogen or at 60–90 °C with in situ-generated hydrogen and catalyst loadings of 0.5–2 mol %. The implemented protocol tolerates a variety of electron-donating and electron-withdrawing functional groups, including halides, phenols, nitriles, unprotected amines, and heterocycles. The reaction can be upscaled to the gram scale. Mechanistic investigations, including deuterium-labeling studies and density functional theory (DFT) calculations, were undertaken to provide a reasonable reaction mechanism, showing that initially formed Z- isomer undergoes fast isomerization to afford the thermodynamically more stable E- isomer.

show abstract

Manganese-Catalyzed Dehydrogenative Silylation of Alkenes Following Two Parallel Inner-Sphere Pathways

Cited by 35 publications

References 49 publications

Manganese-catalyzed hydrogenation, dehydrogenation, and hydroelementation reactions

Manganese-catalyzed hydrogenation, dehydrogenation, and hydroelementation reactions

Manganese Alkyl Carbonyl Complexes: From Iconic Stoichiometric Textbook Reactions to Catalytic Applications

E-Selective Manganese-Catalyzed Semihydrogenation of Alkynes with H₂ Directly Employed or In Situ-Generated

Contact Info

Product

Resources

About

Manganese-Catalyzed Dehydrogenative Silylation of Alkenes Following Two Parallel Inner-Sphere Pathways

Cited by 35 publications

References 49 publications

Manganese-catalyzed hydrogenation, dehydrogenation, and hydroelementation reactions

Manganese-catalyzed hydrogenation, dehydrogenation, and hydroelementation reactions

Manganese Alkyl Carbonyl Complexes: From Iconic Stoichiometric Textbook Reactions to Catalytic Applications

E-Selective Manganese-Catalyzed Semihydrogenation of Alkynes with H2 Directly Employed or In Situ-Generated

Contact Info

Product

Resources

About

E-Selective Manganese-Catalyzed Semihydrogenation of Alkynes with H₂ Directly Employed or In Situ-Generated