Cobalt-Catalyzed Dehydrogenative C-H Silylation of Alkynylsilanes

Cobalt-Catalyzed Reduction of Aldehydes to Alcohols via the Hydroboration Reaction

A method for the reduction of aldehydes with pinacolborane catalyzed by pincer cobalt complexes based on a triazine backbone is developed in this paper. The presented methodology allows for the transformation of several aldehydes bearing a wide range of electron-withdrawing and electron-donating groups under mild conditions. The presented procedure allows for the direct one-step hydrolysis of the obtained intermediates to the corresponding primary alcohols. A plausible reaction mechanism is proposed.

Carboxylate-Catalyzed C-Silylation of Terminal Alkynes

A carboxylate-catalyzed, metal-free C-silylation protocol for terminal alkynes is reported using a quaternary ammonium pivalate as the catalyst and commercially available N,O-bis(silyl)acetamides as silylating agents. The reaction proceeds under mild conditions, tolerates a range of functionalities, and enables concomitant O- or N-silylation of acidic OH or NH groups. A Hammett ρ value of +1.4 ± 0.1 obtained for para-substituted 2-arylalkynes is consistent with the proposed catalytic cycle involving a turnover-determining deprotonation step.

Access to Unsaturated Organogermanes via (De)Hydrosilylation Mediated by Cobalt Complexes

The functionalization of alkynylgermanes using hydrosilanes was accomplished by employing cobalt catalysis. Depending on the reactants used, the reaction can proceed via dehydrogenative coupling or hydrosilylation. Importantly, the presented method is characterized by mild reaction conditions, allowing rapid access to a wide range of organogermanes.

Access to germasiloxanes and alkynylgermanes mediated by earth-abundant species

The reactions between silanols or terminal acetylenes with alkynylgermanes have been accomplished using potassium bis(trimethylsilyl)amide as the catalyst. This strategy has provided an entry point into various organogermanes including germasiloxanes and alkynylgermanes. Remarkably, not only KHMDS but also simple bases such as KOH can serve as efficient catalysts in this process.

Organocalcium-Complex-Catalyzed Dehydrogenative Silylation and Mono/Dihydrosilylation Tandem Reactions of Terminal Alkynes

In principle, catalytic dehydrogenative silylation and mono/dihydrosilylation tandem reactions of terminal alkynes with hydrosilanes provide gem-disilylated alkenes or gem-trisilylated alkanes, but very little progress has been made. Herein, we report organocalcium-complex-catalyzed dehydrogenative silylation and mono/dihydrosilylation tandem reactions of terminal alkynes with hydrosilanes in one pot, which produce gem-disilylated alkenes in moderate yields and gem-trisilylated alkanes in high yields. We also briefly demonstrate that the synthesized gem-disilylated alkenes can be easily transformed into other organosilanes.

Markovnikov-selective double hydrosilylation of challenging terminal aryl alkynes under cobalt and iron catalysis

Geminal bis(silanes) are unique compounds with interesting properties. The most straightforward way to access them is double hydrosilylation of alkynes, which was established only recently. Previous articles about transition metal-catalysed double hydrosilylation show that terminal aryl alkynes are a challenge. We report on cobalt(II) and iron(III) complexes with the easy-to-synthesise N,N,N-tridentate hydrazone ligand being active precatalysts in Markovnikov-selective double hydrosilylation of terminal aryl alkynes. The influence of the hydrazone ligand structure and the potential role of the sodium triethylborohydride activator were studied. Sets of geminal bis(silanes) with two identical or different silyl groups were synthesised, showing the applicability of the reported method.

Silicon-nitrogen bond formation via dealkynative coupling of amines with bis(trimethylsilyl)acetylene mediated by KHMDS

The catalytic synthesis of silylamines mediated by s- and p-block catalysts is largely underdeveloped. Herein, commercially available potassium bis(trimethylsilyl)amide serves as an efficient alternative to transition metal complexes. N-H/Si-C dealkynative coupling was achieved by means of user-friendly main-group catalysis with ample substrate scope and high chemoselectivity.

Catalytic C(sp)–Si cross-coupling silylation of alkynyl bromides with hydrosilanes by palladium catalysis

An unprecedented and convenient Si–C(sp) bond-forming cross-coupling of alkynyl bromides with hydrosilanes has been established for the facile synthesis of alkynylsilanes in good yields and with excellent chemoselectivity.

Photochemical alknylation of hydrosilanes by iron catalysis

Alkynylsilanes is one kind of essential synthetic block in organic chemistry. The established synthetic routes remain some drawbacks regarding to harsh reaction conditions or expensive/rare metal catalyst. Herein, we report...