67082-00-2Relevant academic research and scientific papers
Unveiling the catalytic nature of palladium-N-heterocyclic carbene catalysts in the α-alkylation of ketones with primary alcohols
?etinkaya, Bekir,Ero?lu, Zafer,Gülcemal, Süleyman,Metin, ?nder,Ovezova, Mamajan
supporting information, p. 10896 - 10908 (2021/08/17)
We report herein the synthesis of four new Pd-PEPPSI complexes with backbone-modified N-heterocyclic carbene (NHC) ligands and their application as catalysts in the α-alkylation of ketones with primary alcohols using a borrowing hydrogen process and tandem Suzuki-Miyaura coupling/α-alkylation reactions. Among the synthesized Pd-PEPPSI complexes, complex2chaving 4-methoxyphenyl groups at the 4,5-positions and 4-methoxybenzyl substituents on the N-atoms of imidazole exhibited the highest catalytic activity in the α-alkylation of ketones with primary alcohols (18 examples) with yields reaching up to 95%. Additionally, complex2cwas demonstrated to be an effective catalyst for the tandem Suzuki-Miyaura-coupling/α-alkylation of ketones to give biaryl ketones with high yields. The heterogeneous nature of the present catalytic system was verified by mercury poisoning and hot filtration experiments. Moreover, the formation of NHC-stabilized Pd(0) nanoparticles during the α-alkylation reactions was identified by advanced analytical techniques.
Synthesis of α-Alkylated Ketones via Selective Epoxide Opening/Alkylation Reactions with Primary Alcohols
Gen?, Serta?,Gülcemal, Süleyman,Günnaz, Salih,?etinkaya, Bekir,Gülcemal, Derya
supporting information, p. 5229 - 5234 (2021/07/19)
A new method for converting terminal epoxides and primary alcohols into α-alkylated ketones under borrowing hydrogen conditions is reported. The procedure involves a one-pot epoxide ring opening and alkylation via primary alcohols in the presence of an N-heterocyclic carbene iridium(I) catalyst, under aerobic conditions, with water as the side product.
Electrochemical-Induced Hydrogenation of Electron-Deficient Internal Olefins and Alkynes with CH3OH as Hydrogen Donor
Qin, Hongyun,Yang, Jianjing,Yan, Kelu,Xue, Yaxuan,Zhang, Meichen,Sun, Xuejun,Wen, Jiangwei,Wang, Hua
supporting information, p. 2104 - 2109 (2021/03/15)
Efficient hydrogenation of electron-deficient internal olefins and alkynes access to saturate ketone with CH3OH as a single hydrogen donor under electrochemical conditions has been successfully developed. This hydrogenation strategy can be used to convert electron-deficient internal olefins and alkynes to saturate ketone under electrochemical conditions with exogenous-reductant and a metal catalyst. Mechanistic studies reveal that radical hydrogenation was involved in this transformation. Notably, various electron-deficient internal olefins and alkynes could be tolerated in such an electrochemical hydrogenation synthetic strategy and can be easily scaled up with good efficiency. (Figure presented.).
Borane-Catalyzed, Chemoselective Reduction and Hydrofunctionalization of Enones Enabled by B-O Transborylation
Nicholson, Kieran,Langer, Thomas,Thomas, Stephen P.
, p. 2498 - 2504 (2021/04/13)
The use of stoichiometric organoborane reductants in organic synthesis is well established. Here these reagents have been rendered catalytic through an isodesmic B-O/B-H transborylation applied in the borane-catalyzed, chemoselective alkene reduction and formal hydrofunctionalization of enones. The reaction was found to proceed by a 1,4-hydroboration of the enone and B-O/B-H transborylation with HBpin, enabling catalyst turnover. Single-turnover and isotopic labeling experiments supported the proposed mechanism of catalysis with 1,4-hydroboration and B-O/B-H transborylation as key steps.
Alkylation synthesis method of in-situ catalytic alcohol (by machine translation)
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Paragraph 0147-0149; 0156-0158, (2020/11/01)
The method comprises VIB metal complexes, an auxiliary ligand and a base as a catalytic reaction system, wherein the alcohol serves as an alkylating agent, and the nucleophilic substrate is subjected to in-situ catalytic alkylation reaction in a solvent and an inert gas atmosphere. The catalytic system has a wide application range on a substrate, can catalyze the synthesis of C-N and C-C bond compounds of different structures under mild conditions, and can green synthesize a series of valuable N - alkylation and C - alkylation compounds. (by machine translation)
Efficient Generation and Synthetic Applications of Alkyl-Substituted Siloxycarbenes: Suppression of Norrish-Type Fragmentations of Alkanoylsilanes by Triplet Energy Transfer
Abe, Manabu,Hagiwara, Chihiro,Ishida, Kento,Kusama, Hiroyuki,Yamazaki, Hokuto
, p. 1249 - 1253 (2020/02/04)
Acylsilanes have been known to undergo isomerization to siloxycarbenes under photoirradiation and the thus generated carbenes can be utilized for various synthetic reactions. But this carbene formation is not necessarily efficient with some alkanoylsilanes because Norrish-type fragmentations compete, which limit the synthetic utility of alkanoylsilanes as carbene precursors. In this study, generation of siloxycarbenes from alkanoylsilanes by visible-light-induced energy transfer was examined by using an Ir complex, [Ir{dF(CF3)ppy}2(dtbpy)]PF6, and was successfully applied to the C?C coupling reactions with boronic esters or aldehydes. This methodology efficiently suppressed undesired Norrish-type reactions and broadened synthetic utility of alkanoylsilanes.
Sustainable and Selective Alkylation of Deactivated Secondary Alcohols to Ketones by Non-bifunctional Pincer N-heterocyclic Carbene Manganese
Lan, Xiao-Bing,Ye, Zongren,Liu, Jiahao,Huang, Ming,Shao, Youxiang,Cai, Xiang,Liu, Yan,Ke, Zhuofeng
, p. 2557 - 2563 (2020/05/04)
A sustainable and green route to access diverse functionalized ketones via dehydrogenative–dehydrative cross-coupling of primary and secondary alcohols is demonstrated. This borrowing hydrogen approach employing a pincer N-heterocyclic carbene Mn complex displays high activity and selectivity. A variety of primary and secondary alcohols are well tolerant and result in satisfactory isolated yields. Mechanistic studies suggest that this reaction proceeds via a direct outer-sphere mechanism and the dehydrogenation of the secondary alcohol substrates plays a vital role in the rate-limiting step.
Cobalt-Catalyzed Chemoselective Transfer Hydrogenation of C=C and C=O Bonds with Alkanols
Jiang, Biao-Lin,Ma, Shuang-Shuang,Wang, Meng-Liang,Liu, Dian-Sheng,Xu, Bao-Hua,Zhang, Suo-Jiang
, p. 1701 - 1706 (2019/03/08)
An environmentally benign protocol of chemoselective transfer hydrogenation of C=C and C=O bonds with alkanols under base-free conditions is developed by this study, wherein the cobalt- bidentate phosphine catalyst precursor is commercially available and
Nonbifunctional Outer-Sphere Strategy Achieved Highly Active α-Alkylation of Ketones with Alcohols by N-Heterocyclic Carbene Manganese (NHC-Mn)
Lan, Xiao-Bing,Ye, Zongren,Huang, Ming,Liu, Jiahao,Liu, Yan,Ke, Zhuofeng
supporting information, p. 8065 - 8070 (2019/10/11)
The unusual nonbifunctional outer-sphere strategy was successfully utilized in developing an easily accessible N-heterocyclic carbene manganese (NHC-Mn) system for highly active α-alkylation of ketones with alcohols. This system was efficient for a wide range of ketones and alcohols under mild reaction conditions, and also for the green synthesis of quinoline derivatives. The direct outer-sphere mechanism and the high activity of the present system demonstrate the potential of nonbifunctional outer-sphere strategy in catalyst design for acceptorless dehydrogenative transformations.
Palladium on carbon-catalyzed Α-alkylation of ketones with alcohols as electrophiles: Scope and mechanism
Bennedsen, Niklas R.,Mortensen, Rasmus L.,Kramer, S?ren,Kegn?s, S?ren
, p. 153 - 160 (2019/02/14)
The α-alkylation of ketones with alcohols represents a green strategy for the formation of crucial carbon–carbon bonds since it only produces water as byproduct. In terms of reaction mechanism, the evidence for homogeneous catalysis supports a catalytic hydrogen-borrowing pathway; however, the reaction mechanism has not been investigated for heterogeneous Pd/C catalysts. Here, we report an improved method for α-alkylation of ketones with alcohols using commercially available Pd/C, ubiquitous in organic synthesis labs, as catalyst. The reaction conditions are mild compared to state-of-the-art for both homo- and heterogeneous catalysts, and the developed conditions produces quantitative yields for most ketones and alcohols. A hot filtration experiment and recycling of the catalyst supports the heterogeneous nature of catalysis. Importantly, the reaction mechanism is studied for the first time by a combination of stoichiometric experiments and kinetic analyses by in-situ IR (React-IR).
