Cu-Catalyzed Alkylation of Grignard Reagents: A New Efficient Procedure

Cahiez, Gérard; Chaboche, Christophe; Jézéquel, Michelle

doi:10.1016/s0040-4020(00)00128-9

Cited by 144 publications

(74 citation statements)

References 12 publications

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“…Interestingly, the reaction is inhibited by NMP, which was added as an activator in the related alkylalkyl cross-coupling protocol. [15] A similar effect was also observed in reactions with aryl manganese compounds. [12] Kambe and co-workers described the application of the NiCl 2 /butadiene catalyst system they developed for crosscoupling reactions of R alkyl ÀX with R alkyl ÀMgX to two reactions with phenyl magnesium bromide (Scheme 19).…”

Section: Alkylàmgx (Kumada Coupling)supporting

confidence: 56%

“…However, secondary and tertiary halides, as well as the commercially more attractive alkyl chlorides, proved to be unreactive. [15] As an extension of the protocol developed by Kumada and co-workers [16] as well as Corriu and Masse [17] for nickelcatalyzed cross-coupling with Grignard reagents, Kambe and co-workers reported similar reactions of alkyl bromides, chlorides, and tosylates in 2002 (Scheme 4). [18] Interestingly, the addition of 1,3-butadiene instead of phosphine ligands proved necessary to stabilize the active catalyst and accelerate the reductive elimination of the product.…”

Section: Alkylàmgx (Kumada Coupling)mentioning

confidence: 97%

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Catalysts for Cross‐Coupling Reactions with Non‐activated Alkyl Halides

Frisch¹,

Beller²

2005

Angew Chem Int Ed

872

280

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Despite the problems inherent to metal-catalyzed cross-coupling reactions with alkyl halides, these reactions have become increasingly important during the last few years. Detailed mechanistic investigations have led to a variety of novel procedures for the selective cross-coupling of non-activated alkyl halides bearing beta hydrogen atoms with a variety of organometallic nucleophiles under mild reaction conditions. This Minireview highlights selected examples of metal-catalyzed coupling methods and is intended to encourage chemists to exploit the potential of these approaches in organic synthesis.

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Section: Alkylàmgx (Kumada Coupling)supporting

confidence: 56%

Section: Alkylàmgx (Kumada Coupling)mentioning

confidence: 97%

Catalysts for Cross‐Coupling Reactions with Non‐activated Alkyl Halides

Frisch¹,

Beller²

2005

Angew Chem Int Ed

872

280

View full text Add to dashboard Cite

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“…The cross coupling reaction between compound 3 and hexadecyl magnesium bromide catalyzed by Li 2CuCl4 yielded hexacosanol derivative 4 in a moderate yield (58%) (7,8). Cahiez et al reported the addition of N-methylpyrrolidone improved Cu-catalyzed cross coupling (9). When we applied this method, the yield of compound 4 was improved to 81%.…”

Section: Synthesis Of Hexacosanoic Acidmentioning

confidence: 89%

Chemical Synthesis of a Very Long-Chain Fatty Acid, Hexacosanoic Acid (C26:0), and the Ceramide Containing Hexacosanoic Acid

Yamamoto

Itoh

2015

J Nutr Sci Vitaminol

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Summary Hexacosanoic acid (C26:0) (1), a very long-chain fatty acid, is related to various diseases such as adrenoleukodystrophy (ALD), adrenomyeloneuropathy (AMN) and atherosclerosis. As the level of 1 higher than the normal is related to diseases above, hexacosanoic acid (1) and the ceramide 2, which contains 1, are thought to play an important role in various tissues. Hexacosanoic acid (1) is known to be a waxy solid and to be hard to dissolve in water as well as organic solvents. Due to this physical property, it is not easy to handle hexacosanoic acid (1) in a laboratory. Therefore, efficient chemical synthesis of the compounds 1 and 2 has not been reported. Here, we report a versatile synthetic method for hexacosanoic acid (1) and the ceramide 2 containing the fatty acid 1. Synthesis of hexacosanoic acid (1) was achieved by applying the coupling of two alkyl units as a key step. Ceramide 2 was efficiently synthesized by applying the reported procedure together with hexacosanoic acid (1) synthesized here. This synthetic strategy has an advantage of getting various carbon chain length fatty acids and their ceramides by using a variety of carbon chain units. This method is also applicable for large-scale synthesis. In addition, these compounds 1 and 2 are useful for investigation of details of these compounds related to diseases such as ALD and AMN.

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“…Bicyclic compound 39, which was the key intermediate in the synthesis of («)-gephyrotoxin (1), was transformed to bromide 44 by standard conditions including the LAH-reduction and the subsequent bromination. The saturated side chain was then introduced by copper-mediated alkylation of 44 using Cahiez's procedure, 31 with 45 isolated in 84% yield. The resulting 45 was successfully converted to («)-perhydrogephyrotoxin (49) in 14 steps with an overall yield of 10.3% from 4-pentenoic acid.…”

mentioning

confidence: 99%

Total Syntheses of (±)-Gephyrotoxin and (±)-Perhydrogephyrotoxin

Shirokane

Tanaka

Yoritate

et al. 2015

Bulletin of the Chemical Society of Japan

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This article describes the full details of our total syntheses of gephyrotoxin and perhydrogephyrotoxin. Our central strategy toward the total synthesis is based on the use of an N-methoxy group as a reactivity control element. The N-methoxyamide group enabled unique transformations, involving i) the direct coupling reaction of the N-methoxyamide with an aldehyde, and ii) the amide-selective reductive allylation. These reactions were never accomplished without the assistance of the N-methoxy group. The amide-selective reductive allylation of the N-methoxyamide was especially practical, and excluded a number of extra steps including protecting group manipulations and redox reactions in the total syntheses.Gephyrotoxin (1) is a constituent isolated from skin extracts of a Colombian tropical poison dart frog, Dendrobates histrionicus in 1977 (Figure 1). 1 The structure of gephyrotoxin (1) was elucidated by spectroscopic approaches, and finally determined by X-ray crystallographic analysis. Gephyrotoxin (1) consists of a tricyclic core and two distinct side chains with five stereogenic carbon centers, three of which are connected to the same nitrogen atom. It possesses an array of neurological activities including mild muscarinic activities. Kishi documented the first total synthesis of («)-gephyrotoxin (1) using a set of stereoselective hydrogenation reactions to establish all five stereocenters in 1980.2a Kishi then achieved the enantioselective total synthesis starting from L-pyroglutamic acid, which resulted in disagreement on the absolute configuration of the natural gephyrotoxin (1).2b The absolute structure of 1 remains inconclusive due to the limited supply of the natural alkaloid. In 1983, Hart reported the total synthesis of («)-gephyrotoxin (1) via cyclization of N-acyliminium ion as a key step.2c,2d Shortly after, Overman disclosed the stereoselective total synthesis of 1, whose key steps were the DielsAlder reaction of the amino diene, and stereoselective reduction using stereoelectronic effects.2e The unique structure of gephyrotoxin (1) has continuously inspired the synthetic community, resulting in a number of formal syntheses based on Kishi's route by a multitude of differing strategies. 24 Very recently, Smith reported the enantioselective total synthesis by use of an elegant cascade strategy. 2f In this full paper, we disclose full details of the development of an efficient strategy for synthesis of 1 using an N-methoxy group as a reactivity control element. 5 In particular, utilization of amide-selective nucleophilic addition enabled the concise and efficient total synthesis of 1.Our research group is engaged in a program devoted to the development of efficient strategies using unique properties of a heteroatomheteroatom bond for assembling complex natural products. Incorporation of a heteroatom to a second heteroatom dramatically changes the original reactivities, and enables new transformations, which are not realized with an isolated heteroatom. As proof of this concept, we took an interes...

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Cu-Catalyzed Alkylation of Grignard Reagents: A New Efficient Procedure

Cited by 144 publications

References 12 publications

Catalysts for Cross‐Coupling Reactions with Non‐activated Alkyl Halides

Catalysts for Cross‐Coupling Reactions with Non‐activated Alkyl Halides

Chemical Synthesis of a Very Long-Chain Fatty Acid, Hexacosanoic Acid (C26:0), and the Ceramide Containing Hexacosanoic Acid

Total Syntheses of (±)-Gephyrotoxin and (±)-Perhydrogephyrotoxin

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