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1. Anti-Markovnikov terminal and gem -olefin hydrosilylation using a κ ⁴ -diimine nickel catalyst: selectivity for alkene hydrosilylation over ether C–O bond cleavage

   https://doi.org/10.1039/C8DT04608E  

   Rock, Christopher L.; Trovitch, Ryan J. (January 2019, Dalton Transactions)

   The phosphine-substituted α-diimine Ni precursor, ( Ph2PPr DI)Ni , has been found to catalyze alkene hydrosilylation in the presence of Ph 2 SiH 2 with turnover frequencies of up to 124 h −1 at 25 °C (990 h −1 at 60 °C). Moreover, the selective hydrosilylation of allylic and vinylic ethers has been demonstrated, even though ( Ph2PPr DI)Ni is known to catalyze allyl ester C–O bond hydrosilylation. At 70 °C, this catalyst has been found to mediate the hydrosilylation of ten different gem -olefins, with turnover numbers of up to 740 under neat conditions. Prior and current mechanistic observations suggest that alkene hydrosilylation takes place though a Chalk–Harrod mechanism following phosphine donor dissociation. 

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2. Selective demethylation of O -aryl glycosides by iridium-catalyzed hydrosilylation

   https://doi.org/10.1039/D1CC00496D  

   Jones, Caleb A.; Schley, Nathan D. (June 2021, Chemical Communications)

   null (Ed.)

   The cleavage of alkyl ethers by hydrosilylation is a powerful synthetic tool for the generation of silyl ethers. Previous attempts to apply this transformation to carbohydrate derivatives have been constrained by poor selectivity and preferential reduction of the anomeric position. O -Aryl glycosides are found to be stable under iridium- and borane-catalyzed hydrosilylation conditions, allowing for alkyl ether cleavage without loss of anomeric functionality. A cationic bis(phosphine)iridium complex catalyzes the selective 3-demethylation of a variety of 2,3,4-tri- O -methyl pyranoses, offering a unique approach to 3-hydroxy or 3-acetyl 2,4-di- O -methylpyranoses. 

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3. Manganese Salan Complexes as Catalysts for Hydrosilylation of Aldehydes and Ketones

   https://doi.org/10.3390/catal13040665  

   Almutairi, Nora; Vijjamarri, Srikanth; Du, Guodong (April 2023, Catalysts)

   Manganese has attracted significant recent attention due to its abundance, low toxicity, and versatility in catalysis. In the present study, a series of manganese (III) complexes supported by salan ligands have been synthesized and characterized, and their activity as catalysts in the hydrosilylation of carbonyl compounds was examined. While manganese (III) chloride complexes exhibited minimal catalytic efficacy without activation of silver perchlorate, manganese (III) azide complexes showed good activity in the hydrosilylation of carbonyl compounds. Under optimized reaction conditions, several types of aldehydes and ketones could be reduced with good yields and tolerance to a variety of functional groups. The possible mechanisms of silane activation and hydrosilylation were discussed in light of relevant experimental observations. 

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4. Experimental Approaches for the Synthesis of Low-Valent Metal-Organic Frameworks from Multitopic Phosphine Linkers

   https://doi.org/10.3791/65317  

   Griffin, Samuel E.; Domecus, Grant P.; Cohen, Seth M. (January 2023, Journal of Visualized Experiments)

   Metal-Organic Frameworks (MOFs) are the subject of intense research focus due to their potential applications in gas storage and separation, biomedicine, energy, and catalysis. Recently, low-valent MOFs (LVMOFs) have been explored for their potential use as heterogeneous catalysts, and multitopic phosphine linkers have been shown as a useful building block for the formation of LVMOFs. However, the synthesis of LVMOFs using phosphine linkers requires conditions that are distinct from the majority of the MOF synthetic literature, including the exclusion of air and water and the use of unconventional modulators and solvents, making it somewhat more challenging to access these materials. This work serves as a general tutorial for the synthesis of LVMOFs with phosphine linkers, including information on: 1) judicious choice of metal precursor, modulator, and solvent; 2) experimental procedures, air-free techniques, and required equipment; 3) proper storage and handling of the resultant LVMOFs; and 4) useful characterization methods for these materials. The intention of this report is to lower the barrier and make more accessible this new subfield of MOF research and facilitate advancements toward novel catalytic materials. 

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5. Activator-free single-component Co( i )-catalysts for regio- and enantioselective heterodimerization and hydroacylation reactions of 1,3-dienes. New reduction procedures for synthesis of [L]Co( i )-complexes and comparison to in situ generated catalysts

   https://doi.org/10.1039/d2dt01484j  

   Parsutkar, Mahesh M.; Moore, Curtis E.; RajanBabu, T. V. (June 2022, Dalton Transactions)

   Warren Piers (Ed.)

   Although cobalt( i ) bis-phosphine complexes have been implicated in many selective C–C bond-forming reactions, until recently relatively few of these compounds have been fully characterized or have been shown to be intermediates in catalytic reactions. In this paper we present a new practical method for the synthesis and isolation of several cobalt( i )-bis-phosphine complexes and their use in Co( i )-catalyzed reactions. We find that easily prepared ( in situ generated or isolated) bis-phosphine and (2,6- N -aryliminoethyl)pyridine (PDI) cobalt( ii ) halide complexes are readily reduced by 1,4-bis-trimethylsilyl-1,4-dihydropyrazine or commercially available lithium nitride (Li 3 N), leaving behind only innocuous volatile byproducts. Depending on the structures of the bis-phosphines, the cobalt( i ) complex crystallizes as a phosphine-bridged species [(P∼P)(X)Co I [μ-(P∼P)]Co I (X)(P∼P)] or a halide-bridged species [(P∼P)Co I [μ-(X)] 2 Co I (P∼P)]. Because the side-products are innocuous, these methods can be used for the in situ generation of catalytically competent Co( i ) complexes for a variety of low-valent cobalt-catalyzed reactions of even sensitive substrates. These complexes are also useful for the synthesis of rare cationic [(P∼P)Co I -η 4 -diene] + X − or [(P∼P)Co I -η 6 -arene] + X − complexes, which are shown to be excellent single-component catalysts for the following regioselective reactions of dienes: heterodimerizations with ethylene or methyl acrylate, hydroacylation and hydroboration. The reactivity of the single-component catalysts with the in situ generated species are also documented. 

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