Nickel-Catalyzed Kumada Cross-Coupling Reactions of Tertiary Alkylmagnesium Halides and Aryl Bromides/Triflates

Joshi‐Pangu, Amruta; Wang, Chaoyuan; Biscoe, Mark R.

doi:10.1021/ja202769t

Cited by 170 publications

(69 citation statements)

References 32 publications

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“…Generally, the reaction reaches completion within 4-6 h, although coupling with tertiary alkyl halides required longer reaction times. The results are therefore in general accord with the suggestion by Oshima [9c] that cobalt catalysts are superior to Ni [15] and Cu [16] for the coupling of two quaternary carbon centers. Next we investigated the scope of allyl acetates (Table 3).…”

supporting

confidence: 91%

Cobalt‐Catalyzed Reductive Allylation of Alkyl Halides with Allylic Acetates or Carbonates

Qian¹,

Auffrant²,

Felouat³

et al. 2011

Angew Chem Int Ed

128

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Transition-metal-catalyzed allylic alkylations, using a broad range of metal complexes, have been intensively studied because of their potential applications in the synthesis of new olefinic compounds in particular for total synthesis.[1] Soft nucleophiles are usually used in Pd-, [1] Mo-, [2] Ir-, [3] Ru-, [4] Rh-, [5] Pt-, [6] and even Fe-catalyzed [7] allylic substitutions. Ni, [8] Co, [9] and Cu [10] catalysts allow the use of hard nucleophiles such as alkylzinc or Grignard reagents, but limited functional group compatibility and/or poor regioselectivity can be observed if the system is not designed carefully. To avoid handling the air-and moisture-sensitive organomagnesium and organozinc reagents, straightforward procedures, which do not require organometallic reagents, are highly desirable and many have now been developed. [11] To the best of our knowledge, direct transition-metal-catalyzed alkyl-allyl cross-couplings using in situ generated catalytic organometallic reagents are still unknown. However, a few years ago, we reported a related Co-catalyzed coupling reaction of aryl halides with allylic acetates; [12] these reactions in the presence of an appropriate reducing reagent, gave allylaromatic compounds. Such allylic carboxylates, whilst less reactive than allyl halides, are much more environmentally friendly.Given our previous experience with the direct Cocatalyzed functionalization, including alkylation, [11c] of aryl halides [13] we were interested to take the chemistry further, and herein we report a new and general method for direct reductive cross-coupling of allylic acetates with alkyl halides using a CoBr 2 /Mn system with an acetonitrile/pyridine solvent mixture. The approach accommodates a variety of simple and functionalized alkyl halides and substituted allylic compounds and is experimentally straightforward. Indeed it uses off-theshelf reagents without any particular precautions against air and moisture. First, we investigated the use of the readily available yet poorly reactive ethyl 4-bromobutanoate with a simple allyl acetate as the electrophile. The major challenge here lies in promoting cross-coupling rather than the formation of reduction and homocoupling products.

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supporting

confidence: 91%

Cobalt‐Catalyzed Reductive Allylation of Alkyl Halides with Allylic Acetates or Carbonates

Qian¹,

Auffrant²,

Felouat³

et al. 2011

Angew Chem Int Ed

128

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“…A 1.0 m THF solution of tert ‐butylmagnesium chloride was purchased from Sigma‐Aldrich. NiCl 2 ⋅ 1.5 H 2 O was prepared according to the literature . Unless otherwise noted, other chemicals obtained from commercial suppliers were used without further purification.…”

Section: Methodsmentioning

confidence: 99%

“…NiCl 2 ·1.5 H 2 Ow as prepared according to the literature. [29] Unless otherwise noted, other chemicals obtained from commercial suppliers were used without further purification. 2-Bromobiaryls were prepared by Suzuki-Miyaura cross-coupling reaction between aryl iodides (or aryl bromides) and aryl boronic acids.…”

Section: General Methodsmentioning

confidence: 99%

“…1 (R)-2,2'-Di-tert-butyl-9,9'-spiro-9-silabifluorene (2 d):C ompound 2d was prepared according to the literature method. [29] (R)-9,9'-Spiro-9-silabifluorene 2,2'-bis(trifluoromethanesulfonate) (62.9 mg, 0.10 mmol) and as olution of tert-butylmagnesium chloride in THF (1.0 m,0 .40 mL, 0.40 mmol) were added to as tirred solution of NiCl 2 ·1.5 H 2 O( 1.6 mg, 10 mmol) and 1,3-dicyclohexyl-1H-imidazolium tetrafluoroborate (3.2 mg, 10 mmol) in THF (1.0 mL) at À10 8C. The resultant mixture was stirred at 25 8Cf or 18 h, and then quenched with saturated NH 4 Cl solution (3.0 mL).…”

Section: General Methodsmentioning

confidence: 99%

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Rhodium‐Catalyzed Synthesis of Chiral Spiro‐9‐silabifluorenes by Dehydrogenative Silylation: Mechanistic Insights into the Construction of Tetraorganosilicon Stereocenters

Murai

Takeuchi

Yamauchi

et al. 2016

Chemistry A European J

113

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Mechanistic insight into the construction of quaternary silicon chiral centers by rhodium-catalyzed synthesis of spiro-9-silabifluorenes through dehydrogenative silylation is reported. The C2 -symmetric bisphosphine ligand, BINAP, was effective in controlling enantioselectivity, and axially chiral spiro-9-silabifluorenes were obtained in excellent yields with high enantiomeric excess. Monitoring of the reaction revealed the presence of a monohydrosilane intermediate as a mixture of two constitutional isomers. The reaction proceeded through two consecutive dehydrogenative silylations, and the absolute configuration was determined in the first silylative cyclization. Competitive reactions with electron-rich and electron-deficient dihydrosilanes indicated that the rate of silylative cyclization increased with decreasing electron density on the silicon atom of the starting dihydrosilane. Further investigation disclosed a rare interconversion between the two constitutional isomers of the monohydrosilane intermediate with retention of the absolute configuration.

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“…Similarly, a range of aryl bromides react in good yields and selectivities with tertiary alkyl Grignard reagents in THF at −10 • C in the presence of NiCl 2 ·(H 2 O) 1.5 and the imidazolidinium salt 195 (Scheme 5.43) [121]. While the role of water is not clear, the use of a hydrated nickel source is necessary.…”

Section: Cross-coupling With C(sp 2 )-Electrophilesmentioning

confidence: 99%

Carbon–Carbon‐Bond‐Forming Reactions Mediated by Organomagnesium Reagents

Chemla

Ferreira

Pérez‐Luna

et al. 2013

Metal‐Catalyzed Cross‐Coupling Reactions and More

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IntroductionFirst reported at the beginning of the twentieth century [1], organomagnesiums are very important synthetic tools. In the field of coupling reactions, first examples of transition-metal-mediated reactions have been reported by Gilman and Lichtenwalter [2] with the oxidative homo-coupling of aryl Grignard reagents in the presence of transition metal halides as both catalyst precursors and oxidants. This reaction was later greatly improved by Kharasch [3], who showed that an efficient homo-coupling reaction could be observed with a small amount of CoCl 2 (3 mol%) and an organic halide as a stoichiometric oxidant. This breakthrough was then followed by the report in 1941 on cross-coupling reactions of arylmagnesium bromides with vinylic halides in the presence of various transition metal salts by the same group [4]. Surprisingly, this seminal work remained mainly unexploited, until this reaction was reinvestigated by several groups in the beginning of the 1970s [5]. Thus, Kochi and Tamura [6, 7] described in 1971 the use of Fe(III) salts as catalyst precursors for cross-coupling reactions, while Kumada [8] and Corriu [9] reported the use of nickel for similar transformations [10,11]. At the same time, the group of Normant [12] described the Cu-catalyzed reaction of the Grignard reagents with organic halides, followed by the report of Murahashi [13] on the use of palladium as a catalyst in similar cross-couplings. Most cross-coupling reactions have been performed with unfunctionalized Grignard reagents because no general method for preparing oligofunctional organomagnesium reagents was available. However, the situation is rapidly evolving, thanks to the groundbreaking work of Knochel and coworkers [14] on the preparation of highly functionalized Grignard reagents. In this chapter, the scope and limitations of cross-coupling reactions involving organomagnesium reagents are showcased with select examples from the recent literature with a special focus on functional-group-tolerant procedures. The recent developments of the most challenging transformations including either the use of oligofunctional metallic species or β-hydrogen-containing nucleophiles will be specially highlighted.

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Nickel-Catalyzed Kumada Cross-Coupling Reactions of Tertiary Alkylmagnesium Halides and Aryl Bromides/Triflates

Cited by 170 publications

References 32 publications

Cobalt‐Catalyzed Reductive Allylation of Alkyl Halides with Allylic Acetates or Carbonates

Cobalt‐Catalyzed Reductive Allylation of Alkyl Halides with Allylic Acetates or Carbonates

Rhodium‐Catalyzed Synthesis of Chiral Spiro‐9‐silabifluorenes by Dehydrogenative Silylation: Mechanistic Insights into the Construction of Tetraorganosilicon Stereocenters

Carbon–Carbon‐Bond‐Forming Reactions Mediated by Organomagnesium Reagents

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