Cobalt-catalyzed synthesis of silyl ethers via cross-dehydrogenative coupling between alcohols and hydrosilanes

Cobalt pincer-type complexes demonstrating unique selectivity for the hydroboration reaction of olefins under mild conditions

“…Based on this and our previous studies on pincer cobalt complexes, as well as literature reports, 44–46,57,63–67 we postulate that in the reaction mixture, as a result of activation with pinacolborane or sodium triethylboron hydride, the two forms of the cobalt complex (Co( i ) and Co( iii )) coexist in equilibrium. Either of them can catalyze the process; however, based on recent reports, 66 we assume that the main catalytically active form is Co( i ) (LCo-H).…”

“…59 In the case of the non-anionic form, its lower catalytic activity is probably compensated by the β-silicon effect, stabilizing the alkyl complex and remarkably accelerating the reaction rate. [60][61][62] Based on this and our previous studies on pincer cobalt complexes, as well as literature reports, [44][45][46]57,[63][64][65][66][67] we postulate that in the reaction mixture, as a result of activation with pinacolborane or sodium triethylboron hydride, the two Scheme 9 Experiments verifying the potential formation of borane as a hidden reaction catalyst.…”

“…Recently, we have shown the possibility of their use in the dehydrogenative silylation reactions of silylacetylenes 44 or dehydrogenative coupling of silanes with alcohols. 45 Moreover, we have demonstrated the possibility of controlling the direction of the reaction of silylacetylenes with pinacolborane toward hydroboration or dehydrogenative borylation products depending on the substituents at the triazine ring. 46 Now we present an efficient anti-Markovnikov selective protocol for the hydroboration of a broad range of alkenes (amines, carbonates, ethers, vinylarenes, vinylsilanes, natural products) under mild conditions using an inexpensive and Earth-abundant cobalt complex as a catalyst.…”

Base-catalyzed addition of silylacetylenes to ketones: a route to protected tertiary propargyl alcohols

“…[27][28][29][30][31][32][33][34][35][36][37] The application of Earth-abundant species as catalysts have gained recent significant attention in organic chemistry. [38][39][40][41][42][43][44][45][46][47][48][49] Considering our recent success in activating organometalloids under sustainable catalysis, [50][51][52][53][54][55][56] we reasoned that an appropriate catalytic manifold could provide an efficient platform to generate diversified libraries of protected propargyl alcohols. To address the limitations of previously mentioned methods, herein we report the KHMDS-catalyzed addition of silylacetylenes to ketones.…”

Co‐catalyzed Selective syn‐Hydrosilylation of Internal Alkynes

“…Given our recent success in incorporating readily available and cost‐effective cobalt complexes into organometallic synthesis, we hypothesized that an appropriate catalytic system could serve as a sustainable platform for producing diverse libraries of vinylsilanes [51–53] . Significantly, the subject of Co‐catalyzed hydrosilylation for internal alkynes, especially symmetrical ones, was limited to a few examples up until now [32,33,38–46] .…”