Highly Selective Manganese(I)/Lewis Acid Cocatalyzed Direct C−H Propargylation Using Bromoallenes

Zhu, Can; Schwarz, J. Luca; Cembellín, Sara; Greßies, Steffen; Glorius, Frank

doi:10.1002/anie.201710835

Cited by 73 publications

(25 citation statements)

References 90 publications

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“…Recently, the Glorius group developed two important methods for the C–H propargylation and 2-(indolyl)methylation of indoles using substituted bromoallenes and 4-ethynyl benzoxazinanones ( Scheme 110L and M ). 666 , 667 Propargylation is a challenging transformation, as the corresponding allenylation might instead occur more easily. For this Mn-catalysed process, the use of BPh 3 as Lewis acid and a catalytic amount of H 2 O proved crucial for obtaining good yields and selectivity (with respect to the allene product).…”

Section: Heterocyclic Dgs In C–h Functionalisationmentioning

confidence: 99%

“…The reaction works well with a variety of functionalised allenes, including 1,3,3-trialkyl, 3,3-dialkyl (giving terminal alkyne products), 1,3-dialkyl and 1-monoalkyl allenes, and with other heterocyclic substrates such as pyrroles and (benzo)thiophenes ( Scheme 110L ). 666 A robustness screening was also performed for this reaction, showing compatibility with functionalities such as aniline, furan, ketones, amides and acetals. The use of 4-ethynyl benzoxazinanones, still under Mn catalysis, results in the C–H (2-indolyl)methylation of indoles and other heterocycles via alkyne insertion into the intermediate manganacycle, release of CO 2 , formation of an allene–Mn intermediate complex, and cyclisation with the nitrogen nucleophile ( Scheme 110M ).…”

Section: Heterocyclic Dgs In C–h Functionalisationmentioning

confidence: 99%

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A comprehensive overview of directing groups applied in metal-catalysed C–H functionalisation chemistry

et al. 2018

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Section: Heterocyclic Dgs In C–h Functionalisationmentioning

confidence: 99%

Section: Heterocyclic Dgs In C–h Functionalisationmentioning

confidence: 99%

A comprehensive overview of directing groups applied in metal-catalysed C–H functionalisation chemistry

et al. 2018

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“…The use of synergistic catalysis has been recognized as a powerful approach for expanding the scope of both strategies and developing valuable transformations [33][34][35][36][37][38][39][40][41] . Along these lines, our group has reported a dual catalytic strategy that enhances the nucleophilicity of the aldimine esters by chelating them with copper co-catalysts to enable the APS reaction 42 .…”

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confidence: 99%

Collective synthesis of acetylenic pharmaceuticals via enantioselective Nickel/Lewis acid-catalyzed propargylic alkylation

et al. 2021

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Chiral acetylenic derivatives are found in many bioactive compounds and are versatile functional groups in organic chemistry. Here, we describe an enantioselective nickel/Lewis acid-catalyzed asymmetric propargylic substitution reaction from simple achiral materials under mild condition. The introduction of a Lewis acid cocatalyst is crucial to the efficiency of the transformation. Notably, we investigate this asymmetric propargylic substitution reaction for the development of a range of structurally diverse natural products. The power of this strategy is highlighted by the collective synthesis of seven biologically active compounds: (−)-Thiohexital, (+)-Thiopental, (+)-Pentobarbital, (−)-AMG 837, (+)-Phenoxanol, (+)-Citralis, and (−)-Citralis Nitrile.

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“…Earth-abundant 3d metal catalysts provide prospect for less toxic metals in C-H activations [216] with notable advances in manganese-catalyzed C-H activation [258, 168c] by Kuninobu/Takai, [259] Wang, [260,122] and Ackermann, [261, 128, 132, 147b, 186b] among others. [140,262,127] Despite the indisputable progress, manganese-catalyzed-C-H functionalizations continue to be largely limited to homogeneous catalysis.…”

Section: Catalystmentioning

confidence: 99%

Chelation-Assisted C–H Activation by Ruthenium and Osmium Catalysts and Recyclable Hybrid Catalysts

Isaac¹

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TStransition state wt% weight by volume Very recently, the group of Ackermann reported on visible-light-induced ruthenium-catalyzed meta-C-H alkylation at ambient temperature (Scheme 1.2.41). [94] Notably, the photocatalytic reactions were performed under exceedingly mild reaction conditions at ambient temperature and without any additional exogeneous photocatalysts. Around the same time, Greaney also reported similar remote C-H alkylations with alkyl iodide under visible-light induced conditions. [95] Scheme 1.2.41 Visible-light-induced ruthenium-catalyzed meta-C-H alkylation.In addition to the aforementioned site-selective distal C-C bond formation, ruthenium catalysis enabled other meta-functionalizations, such as sulfonylations, [96] halogenations, [97] and nitrations (Scheme 1.2.42). [98] Scheme 1.2.42 Ruthenium-catalyzed distal C-H functionalizations, halogenations, sulfonylations, and nitrations.In contrast to the indisputable progress in meta-selective C-H functionalizations, general procedures for ruthenium-catalyzed para-C-H functionalization are under developed. Frost [99] and Ackermann [90] independently reported on ruthenium-catalyzed para-C-H alkylations of pyrimidylanilines 167 with α-halo carbonyl compound 168 (Scheme 1.2.43). Notably, Frost suggested that the formation of fourmembered ruthenacycle 170 is the key intermediate. Scheme 1.2.43 Ruthenium-catalyzed para-C-H alkylations.Later, Zhao/Lan and Liang utilized a similar ruthenium-catalyzed para-C-H functionalization method to achieve mono-and difluoroalkylations (Scheme 1.2.44). [100] Unlike the mechanistic hypothesis offered by Frost, Zhao/Lan proposed that ortho-C-H ruthenation enabled the para-selectivity, although detailed experimental support was not provided.Recently, Yi and co-workers reported on unprecedented osmium(II)-catalyzed C-H activation (Scheme 1.3.8). [112] While transition metal-catalyzed C-H annulation has been well established, [113] the osmium complex was firstly employed in this study. Notably, the use of internal oxidant brought about less atom efficiency in this reaction, while a wide range of substrates was amenable. Additionally, experimental mechanistic studies revealed that the C-H bond scission process is irreversible, while osmium(II) carboxylate-assisted C-H activation was studied by computational DFT analysis.Despite the indisputable progress, manganese-catalyzed C-H activation had been put in the shade before Kuninobu and Takai disclosed a seminal study in 2007. [121] Thereby, a manganese(I) complex catalytically enabled C-H activation of arenes 226 with aldehydes 227 and Et3SiH, affording silylated alcohols 228. Additionally, the catalytic cycle was proposed, in which Mn-C bond was suggested as a manganese(III)-hydride species 229 is formed via an oxidative addition. The exact structure of the active catalyst has thus far remained elusive, while recent manganese-catalyzed hydroarylation reactions are generally proposed to undergo redox-neutral isohypsic pathway. Thereafter, a migratory insertion foll...

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Highly Selective Manganese(I)/Lewis Acid Cocatalyzed Direct C−H Propargylation Using Bromoallenes

Cited by 73 publications

References 90 publications

A comprehensive overview of directing groups applied in metal-catalysed C–H functionalisation chemistry

A comprehensive overview of directing groups applied in metal-catalysed C–H functionalisation chemistry

Collective synthesis of acetylenic pharmaceuticals via enantioselective Nickel/Lewis acid-catalyzed propargylic alkylation

Chelation-Assisted C–H Activation by Ruthenium and Osmium Catalysts and Recyclable Hybrid Catalysts

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