Cobalt-Catalyzed (<i>E</i>)-Selective Hydrosilylation of 1,3-Enynes for the Synthesis of 1,3-Dienylsilanes

Kong, Degong; Hu, Bowen; Yang, Min; Xia, Haiping; Chen, Dafa

doi:10.1021/acs.organomet.1c00219

Cited by 14 publications

(3 citation statements)

References 68 publications

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“…Recently, earth-abundant metal catalysts for selective alkyne hydrosilylation are more attractive due to their low cost, long-term sustainability, and low toxicity . Our group has been interested in the discovery of new cobalt-catalyzed transformations. , Although a variety of Co-based catalysts have been revealed in hydrosilylation of simple alkynes and 1,3-enynes in high site- and stereoselectivity (Scheme a), single Si–H addition was exclusively involved in these processes. Cascade reactions of two Si–H bonds sequentially to a single unsaturated molecule in high chemo-, site-, and stereoselectivity remains unknown.…”

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confidence: 99%

Cobalt-Catalyzed Sequential Site- and Stereoselective Hydrosilylation of 1,3- and 1,4-Enynes

Zhao

Meng

2022

J. Am. Chem. Soc.

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Catalytic sequential hydrosilylation of 1,3-enynes and 1,4-enynes promoted by cobalt complexes derived from bisphosphines are presented. Site- and stereoselective Si–H addition of primary silanes to 1,3-enynes followed by sequential intramolecular diastereo- and enantioselective Si–H addition afforded enantioenriched cyclic alkenylsilanes with simultaneous construction of a carbon-stereogenic center and a silicon-stereogenic center. Reactions of 1,4-enynes proceeded through sequential isomerization of the alkene moiety followed by site- and stereoselective hydrosilylation. A wide range of alkenylsilanes were afforded in high efficiency and selectivity. Functionalization of the enantioenriched silanes containing a stereogenic center at silicon delivered a variety of chiral building blocks that are otherwise difficult to access.

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confidence: 99%

Cobalt-Catalyzed Sequential Site- and Stereoselective Hydrosilylation of 1,3- and 1,4-Enynes

Zhao

Meng

2022

J. Am. Chem. Soc.

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“…[1] Efforts on this aspect have led to the development of a variety of cobalt catalysts for alkyne hydrosilylation reactions that are useful for the preparation of vinylsilanes. [2] Representative catalysts of the type include cobalt pyridine imine complexes, [3] cobalt bipyridine complexes, [4] cobalt imidazole complexes, [5] cobalt phosphine complexes, [6] and cobalt N-heterocyclic carbene (NHC) complexes. [7] Along with the diversity of the ligands in these cobalt catalysts, the oxidation states of the cobalt centers also vary.…”

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confidence: 99%

Low‐coordinate cobalt(0) N‐heterocyclic carbene complexes as catalysts for hydrosilylation of alkynes

Bai

Sun

Wang

et al. 2022

Applied Organom Chemis

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Among the great efforts of developing cobalt-based catalysts for hydrosilylation reactions, cobalt (II) and cobalt(I) complexes are the extensively studied ones. In contrast, explorations on cobalt(0) complexes are relatively rare. Presented herein is the investigation on the catalytic performance of low-coordinate cobalt(0) N-heterocyclic carbene (NHC) complexes in the hydrosilylation reaction of alkynes, which disclosed the fine performance of [(CyIDep)Co(η 2 -CH 2 CHSiMe 3 ) 2 ] (CyIDep denotes for a 1,3-bis (2 0 ,6 0 -diethylphenyl)imidazole-2-ylidene that bears fused cyclohexyl group on the imidazole backbone) in catalyzing the syn-addition of a series of symmetric and unsymmetric internal alkynes with H 2 SiPh 2 , producing vinylsilanes with high regio-selectivity. Mechanistic study indicates that the catalytic reaction likely proceeds on a cobalt(0)/cobalt(II) cycle and that the high selectivity is governed by the steric nature of the NHC ligand.

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“…As the addition reactions of alkynes might produce regio- and/or stereoisomers of the alkene products, selectivity control is the prerequisite for their practical usage. The great efforts toward this goal have led to the development of a large number of selective addition reactions of alkynes, particularly for alkynes having substantial differences in the electronic and/or steric nature of the substituents. − However, selective addition reactions of internal alkynes that feature similar substituents still present a big challenge. − …”

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confidence: 99%

Cobalt-Catalyzed Regio- and Stereoselective Hydrosilylation of Alk-2-ynes with Tertiary Silanes

Yang

Wang

et al. 2023

Organometallics

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Selectivity control in the addition reactions of internal alkynes that bear two similar substituents presents a big challenge in modern organic synthesis. Herein we report that β-(E)-selective hydrosilylation of alk-2-ynes with tertiary silanes can be achieved by using Co 2 (CO) 8 as the catalyst. Under the catalytic reaction conditions, a wide range of alk-2-ynes can be converted into vinylsilanes with the β-(E) isomers as the major or sole hydrosilylation products. Mechanistic studies suggest that alkynebridged dicobalt species are the likely intermediates. Steric repulsion between substituents in alkenyl-bridged dicobalt silyl intermediates is proposed as the key factor inducing the observed regioselectivity.

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Cobalt-Catalyzed (E)-Selective Hydrosilylation of 1,3-Enynes for the Synthesis of 1,3-Dienylsilanes

Cited by 14 publications

References 68 publications

Cobalt-Catalyzed Sequential Site- and Stereoselective Hydrosilylation of 1,3- and 1,4-Enynes

Cobalt-Catalyzed Sequential Site- and Stereoselective Hydrosilylation of 1,3- and 1,4-Enynes

Low‐coordinate cobalt(0) N‐heterocyclic carbene complexes as catalysts for hydrosilylation of alkynes

Cobalt-Catalyzed Regio- and Stereoselective Hydrosilylation of Alk-2-ynes with Tertiary Silanes

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