Lanthanum(III) Triflate Catalyzed Direct Amidation of Esters

Morimoto, Hiroyuki; Fujiwara, Risa; Shimizu, Yoshiaki; Morisaki, Kazuhiro; Ohshima, Takashi

doi:10.1021/ol500593v

Cited by 146 publications

(86 citation statements)

References 59 publications

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“…Hence, the reaction displays excellent chemoselectivity. However, the ester functionality was not compatible and, as described in the literature,14 full aminolysis was achieved within 30 min. The scope of the reaction was further expanded to include more demanding aliphatic organofluorides (Scheme ).…”

Section: Resultsmentioning

confidence: 90%

Mild and Selective Activation and Substitution of Strong Aliphatic CF Bonds

Janjetovic

Träff

Hilmersson

2015

Chemistry A European J

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A procedure for chemoselectively manipulating the strong aliphatic C-F bond with direct transformation into a C-N bond under mild conditions is reported. The activation and subsequent substitution of primary alkyl fluorides is mediated by La[N(SiMe3)2]3, and results in high to excellent yields of tertiary amines. The methodology displays high selectivity towards the C(sp(3))-F bond, and a variety of secondary amines are applicable as nucleophiles. Mechanistic investigations reveal a reaction that is first order with respect to [La[N(SiMe3)2]3], [R(1)R(2)NH], and [alkyl fluoride], and a 6-membered cyclic transition state is proposed. In addition, (1)H NMR spectroscopy shows that La[N(SiMe3)2]3 is the active species involved in the substitution and that protonolysis of the amine, yielding La[NR(1)R(2)]3, lowers the reactivity.

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Section: Resultsmentioning

confidence: 90%

Mild and Selective Activation and Substitution of Strong Aliphatic CF Bonds

Janjetovic

Träff

Hilmersson

2015

Chemistry A European J

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“…As esters are stable compounds, reaction conditions such as high temperature and pressure and a strong base are required for conversion from the ester to an amide. Hence, in recent years, mild amidation using a metal or an organic base as a catalyst has been reported [8][9][10]. In this study, we reported that the direct amidation reaction of tryptoline methyl ester derivatives 4-7 under catalyst-free mild conditions gave corresponding amides 8-11 in high yield.…”

Section: Chemistrymentioning

confidence: 77%

Synthesis of All Stereoisomers of 1-(4-Methoxyphenyl)-2,3,4,9-tetrahydro-N-methyl-1H-pyrido[3,4-b]indole-3-carboxamide

Onda

Higashida

Hirano

et al. 2018

Molbank

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Abstract:In this study, all four stereoisomers of tryptoline or tetrahydro-β-carboline were synthesized in high yields by the catalyst-free amidation of methyl ester using methylamine under mild conditions. All isomers of the obtained amide and the precursor methyl ester were subjected to cell viability measurements on HeLa cells. The results indicated that the stereochemistry of the derivatives is clearly related to cell viability.

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“…To our delight, addition of 10 mol % scandium trifluoromethanesulfonate (Sc(OTf) 3 ) [16] promoted the acylation of 9 at room temperature, leading to the formation of 11 in 86 % yield without serious epimerization (11/12 = > 95:5, entry 4). Other Lewis acids (Y(OTf) 3 and La(OTf) 3 ) [17] gave poor results because the corresponding ketene would be formed, leading to a mixture of 11 and its epimer 12 (entries 5 and 6).…”

Section: Resultsmentioning

confidence: 99%

Total Synthesis and Structure Elucidation of JBIR‐39: A Linear Hexapeptide Possessing Piperazic Acid and γ‐Hydroxypiperazic Acid Residues

Yoshida

Sekioka

Izumikawa

et al. 2014

Chemistry A European J

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The total synthesis and stereochemical structural elucidation of JBIR-39, containing four nonproteinogenic piperazic acid (Piz) residues, is reported. The synthesis includes Sc(OTf)3 -catalyzed acylation of a Piz(γ-OTBS) derivative with piperazic acid chloride, providing the desired Piz-Piz(γ-OTBS) dipeptide in high yield without epimerization. After assembling two additional Piz moieties and (S)-isoleucic acid at the N-terminus, amidation with the (R)-α-methylserine ester at the C-terminus, and deprotection afforded the desired (2R,8S)-hexapeptide, which is the assumed structure of JBIR-39. Although the spectral data of the (2R,8S)-hexapeptide was not identical to JBIR-39, further synthesis of three stereoisomers confirmed the stereochemical structure of JBIR-39 to be (2S,6S,8S,11R,16S,21R,26S,27S).

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Lanthanum(III) Triflate Catalyzed Direct Amidation of Esters

Cited by 146 publications

References 59 publications

Mild and Selective Activation and Substitution of Strong Aliphatic CF Bonds

Mild and Selective Activation and Substitution of Strong Aliphatic CF Bonds

Synthesis of All Stereoisomers of 1-(4-Methoxyphenyl)-2,3,4,9-tetrahydro-N-methyl-1H-pyrido[3,4-b]indole-3-carboxamide

Total Synthesis and Structure Elucidation of JBIR‐39: A Linear Hexapeptide Possessing Piperazic Acid and γ‐Hydroxypiperazic Acid Residues

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