Regioselective Silylations of Propargyl and Allyl Pivalates through Ca-Promoted Reductive C(sp<sup>3</sup>)–O Bond Cleavage

Zhang, Tianyuan; Zheng, Suhua; Kobayashi, Taro; Maekawa, Hirofumi

doi:10.1021/acs.orglett.1c02532

Cited by 15 publications

(5 citation statements)

References 42 publications

(27 reference statements)

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“…On the other hand, our group and many others have actively investigated ruthenium-and copper-catalyzed propargylic substitution reactions of propargylic alcohol derivatives with nucleophiles as well as their enantioselective versions, recognized as one of the most efficient approaches to obtain propargylic substituted compounds. [9][10][11] A variety of nucleophiles including carbon-, [12] nitrogen-, [13] oxygen-, [13b,14] sulfur-, [11e,13b,15] phosphorus-, [13b,16] hydride-, [11b,17] and silicon-centered nucleophiles [18] were applied successfully to afford the corresponding propargylic substituted products. However, the successful example of propargylic substitution reactions with Nmonosubstituted hydrazones as ambident nucleophiles has not been reported until now.…”

Section: Introductionmentioning

confidence: 99%

Ruthenium‐ and Copper‐Catalyzed Propargylic Substitution Reactions of Propargylic Alcohol Derivatives with Hydrazones

Liu

Tanabe

Kuriyama

et al. 2021

Chemistry A European J

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Ruthenium-and copper-catalyzed propargylic substitution reactions of propargylic alcohol derivatives with Nmonosubstituted hydrazones as ambident nucleophiles are achieved in which N-monosubstituted hydrazones exhibit impressive different reactivities depending on different catalytic systems, behaving as carbon-centered nucleophiles to give the corresponding propargylic alkylated products in ruthenium catalysis, or as nitrogen-centered nucleophiles to afford the corresponding propargylic aminated products in copper catalysis. DFT calculations were carried out to investigate the detailed reaction pathways of these two systems. Further transformation of propargylic substituted products affords the corresponding multisubstituted pyrazoles as cyclization products in good to high yields.

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Section: Introductionmentioning

confidence: 99%

Ruthenium‐ and Copper‐Catalyzed Propargylic Substitution Reactions of Propargylic Alcohol Derivatives with Hydrazones

Liu

Tanabe

Kuriyama

et al. 2021

Chemistry A European J

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“…However, metallic reagents and alkyl triflates suffer from instability against air, moisture, and high temperature, which hinders the use of such C–Si coupling as a convenient and scalable tool in both the laboratory and industrial settings. While transition metals catalyze silylation of allyl and propargyl esters to afford synthetically useful allylsilanes and allenyl silanes (Scheme , route 5), the development of a universal method that enables the formation of a variety of C(sp 3 )–Si bonds is still a significant challenge.…”

Section: Introductionmentioning

confidence: 99%

Diverse Alkyl–Silyl Cross-Coupling via Homolysis of Unactivated C(sp³)–O Bonds with the Cooperation of Gold Nanoparticles and Amphoteric Zirconium Oxides

et al. 2023

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Since C(sp3)–O bonds are a ubiquitous chemical motif in both natural and artificial organic molecules, the universal transformation of C(sp3)–O bonds will be a key technology for achieving carbon neutrality. We report herein that gold nanoparticles supported on amphoteric metal oxides, namely, ZrO2, efficiently generated alkyl radicals via homolysis of unactivated C(sp3)–O bonds, which consequently promoted C(sp3)–Si bond formation to give diverse organosilicon compounds. A wide array of esters and ethers, which are either commercially available or easily synthesized from alcohols participated in the heterogeneous gold-catalyzed silylation by disilanes to give diverse alkyl-, allyl-, benzyl-, and allenyl silanes in high yields. In addition, this novel reaction technology for C(sp3)–O bond transformation could be applied to the upcycling of polyesters, i.e., the degradation of polyesters and the synthesis of organosilanes were realized concurrently by the unique catalysis of supported gold nanoparticles. Mechanistic studies corroborated the notion that the generation of alkyl radicals is involved in C(sp3)–Si coupling and the cooperation of gold and an acid–base pair on ZrO2 is responsible for the homolysis of stable C(sp3)–O bonds. The high reusability and air tolerance of the heterogeneous gold catalysts as well as a simple, scalable, and green reaction system enabled the practical synthesis of diverse organosilicon compounds.

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“…Traditional methods for the synthesis of propargylsilane usually require harsh reaction conditions and/or the use of highly reactive propargylic Grignard reagents or alkynyl lithium reagents 19 – 22 . Only limited examples realized efficient synthesis of propargylsilane under mild conditions 23 – 26 .…”

Section: Introductionmentioning

confidence: 99%

Regio- and enantioselective CuH-catalyzed 1,2- and 1,4-hydrosilylation of 1,3-enynes

Wang,

Li,

Yang

et al. 2023

Nat Commun

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We report a copper-catalyzed ligand-controlled selective 1,2- and 1,4-hydrosilylation of 1,3-enynes, which furnishes enantiomerically enriched propargyl- and 1,2-allenylsilane products in high yields with excellent enantioselectivities (up to 99% ee). This reaction proceeds under mild conditions, shows broad substrate scope for both 1,3-enynes and trihydrosilanes, and displays excellent regioselectivities. Mechanistic studies based on deuterium-labeling reactions and density functional theory (DFT) calculations suggest that allenylcopper is the dominant reactive intermediate under both 1,2- and 1,4-hydrosilylation conditions, and it undergoes metathesis with silanes via selective four-membered or six-membered transition state, depending on the nature of the ligand. The weak interactions between the ligands and the reacting partners are found to be the key controlling factor for the observed regioselectivity switch. The origin of high enantiocontrol in the 1,4-hydrosilylation is also revealed by high level DLPNO-CCSD(T) calculations.

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Regioselective Silylations of Propargyl and Allyl Pivalates through Ca-Promoted Reductive C(sp³)–O Bond Cleavage

Cited by 15 publications

References 42 publications

Ruthenium‐ and Copper‐Catalyzed Propargylic Substitution Reactions of Propargylic Alcohol Derivatives with Hydrazones

Ruthenium‐ and Copper‐Catalyzed Propargylic Substitution Reactions of Propargylic Alcohol Derivatives with Hydrazones

Diverse Alkyl–Silyl Cross-Coupling via Homolysis of Unactivated C(sp³)–O Bonds with the Cooperation of Gold Nanoparticles and Amphoteric Zirconium Oxides

Regio- and enantioselective CuH-catalyzed 1,2- and 1,4-hydrosilylation of 1,3-enynes

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Regioselective Silylations of Propargyl and Allyl Pivalates through Ca-Promoted Reductive C(sp3)–O Bond Cleavage

Cited by 15 publications

References 42 publications

Ruthenium‐ and Copper‐Catalyzed Propargylic Substitution Reactions of Propargylic Alcohol Derivatives with Hydrazones

Ruthenium‐ and Copper‐Catalyzed Propargylic Substitution Reactions of Propargylic Alcohol Derivatives with Hydrazones

Diverse Alkyl–Silyl Cross-Coupling via Homolysis of Unactivated C(sp3)–O Bonds with the Cooperation of Gold Nanoparticles and Amphoteric Zirconium Oxides

Regio- and enantioselective CuH-catalyzed 1,2- and 1,4-hydrosilylation of 1,3-enynes

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Regioselective Silylations of Propargyl and Allyl Pivalates through Ca-Promoted Reductive C(sp³)–O Bond Cleavage

Diverse Alkyl–Silyl Cross-Coupling via Homolysis of Unactivated C(sp³)–O Bonds with the Cooperation of Gold Nanoparticles and Amphoteric Zirconium Oxides