Iridium catalysed C-3 alkylation of oxindole with alcohols under solvent free thermal or microwave conditions

Grigg, Ronald; Whitney, Simon; Sridharan, Visuvanathar; Keep, Ann; Derrick, Andrew

doi:10.1016/j.tet.2009.03.065

Cited by 59 publications

(23 citation statements)

References 57 publications

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“…[12] Such compounds often present substituents at the 3-position, which are normally introduced by the use of organic halides.O wing to the presence of af ree amine in this cyclic amide,c arbon-carbon bond formation by the method described herein must be performed selectively to avoid the amination reaction. [13] The manganese-catalyzed reaction of 2-oxindole with alcohols bearing aryl, heteroaryl, and alkyl groups under the previously optimized conditions provided the CÀCc oupled products 8a-d in excellent yields (81-92 %, Scheme 3a).…”

Section: Angewandte Chemiementioning

confidence: 99%

“…Therelevance of the basic medium for both catalyst activation and aldol condensation led us to analyze different bases.W e obtained the best result when using cesium carbonate ( Table 1, entries 5-7). Forfurther optimization, we examined other critical parameters,such as the catalyst loading, solvent, base concentration, and temperature ( Table 1, entries [8][9][10][11][12][13][14][15]. Finally,w es elected the reaction of 4a (1 mmol), 5a (1.2 mmol), 3 (0.02 mmol), and Cs 2 CO 3 (0.05 mmol) in tertamyl alcohol at 140 8 8Cf or 22 ha so ptimal conditions,w hich gave 6a in 88 %y ield ( Table 1, entry 14).…”

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confidence: 99%

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Manganese‐Catalyzed Hydrogen‐Autotransfer C−C Bond Formation: α‐Alkylation of Ketones with Primary Alcohols

et al. 2016

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A novel catalytic hydrogen-autotransfer protocol for the atom-efficient α-alkylation of ketones with readily available alcohols is presented. The use of manganese complexes bearing non-innocent PNP pincer ligands enabled the functionalization of a broad range of valuable ketones, including 2-oxindole, estrone 3-methyl ether, and testosterone. Mechanistic investigations suggest the participation of an intramolecular amidate-assisted alcohol-dehydrogenation process.

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Section: Angewandte Chemiementioning

confidence: 99%

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confidence: 99%

Manganese‐Catalyzed Hydrogen‐Autotransfer C−C Bond Formation: α‐Alkylation of Ketones with Primary Alcohols

et al. 2016

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“…However, the reaction was limited to aromatic alcohols, and low yields were observed when aliphatic alcohols were used, even after long reaction times. Aliphatic alcohols were found to be good alkylating agents in their further study on the alkylation of oxindole 8d. In our current study, several transition metal catalysts have been screened, and we found that Pd/C and RuCl 2 (PPh 3 ) 3 /DPEphos showed high catalytic activities for the regioselective alkylation of indoles with various types of alcohols, including aliphatic alcohols (Scheme ).…”

Section: Introductionmentioning

confidence: 70%

Transition‐Metal‐Catalyzed Regioselective Alkylation of Indoles with Alcohols

Putra¹,

Takigawa²,

Tanaka³

et al. 2013

Eur J Org Chem

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The regioselective alkylation of indoles with alcohols as alkylating reagents was developed by using Pd/C or RuCl2(PPh3)3/DPEphos {DPEphos = bis[(2‐diphenylphosphanyl)phenyl] ether}as catalysts. The reaction of indole with benzyl alcohol in the presence of Pd/C and K2CO3 at 80 °C for 24 h without any solvent under in air yielded 90 % of 3‐benzylindole. The corresponding 3‐benzylindole was obtained in 99 % yield when the reaction was catalyzed by RuCl2(PPh3)3/DPEphos in the presence of K3PO4 at 165 °C for 24 h under argon. Several types of alcohols were treated with indoles under these conditions to give the corresponding 3‐alkylated indoles in high yields (up to 99 %). This reaction may involve the catalyst‐mediated transformation of alcohols to aldehydes, nucleophilic addition of indole to the resulting aldehydes accompanied by dehydration, and then hydrogenation.

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“…50 A wide range of aromatic, heteroaromatic, and aliphatic alcohols were used successfully in this reaction. This reaction was also carried out using iridium chloro-bridged compound [Cp*IrCl 2 ] 2 as an effective catalyst under solvent-free thermal or microwave conditions 51 and also using an indenefunctionalized mesoporous iridium catalyst.…”

Section: Reactions With Alcoholsmentioning

confidence: 99%