Silylcupration and Copper-Catalyzed Carbomagnesiation of Ynamides: Application to Aza-Claisen Rearrangement

Yasui, Hiroto; Yorimitsu, Hideki; Oshima, Koichiro

doi:10.1246/bcsj.81.373

Cited by 46 publications

(26 citation statements)

References 22 publications

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“…[12] A number of protocols was developed for the silylmetalation of ynamides (Scheme 1). Silylcupration [13] and the Pd 0 -catalyzed silylstannylation [14] afford a-metalated Z-b-silylenamides. Conversely, the Pd 0 -catalyzed silylboration reaction gives b-metalated Z-a-silylenamides.…”

mentioning

confidence: 99%

Trans‐Selective Radical Silylzincation of Ynamides

Romain¹,

Fopp²,

Chemla³

et al. 2014

Angew Chem Int Ed

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The silylzincation of terminal ynamides is achieved through a radical-chain process involving (Me3Si)3SiH and R2Zn. A potentially competing polar mechanism is excluded on the basis of diagnostic control experiments. The unique feature of this addition across the C≡C bond is its trans selectivity. One-pot electrophilic substitution of the C(sp2)-Zn bond by Cu(I)-mediated C-C bond formation and subsequent manipulation of the C(sp2)-Si bond provides a modular access to Z-α,β-disubstituted enamides.

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mentioning

confidence: 99%

Trans‐Selective Radical Silylzincation of Ynamides

Romain¹,

Fopp²,

Chemla³

et al. 2014

Angew Chem Int Ed

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“…Transmetallation between [(IPr)CuCl] and ad ialkylzincr eagent would form an alkylcopper species, 5.T he carbonyl group on the ynamide moiety would act as adirecting group in the subsequent carbocupration process, forming the alkenylcopper species 6 in ar egioselective manner. [19][20][21] Transmetalation between 6 anda na lkylzinc species would provide an alkenylzinc species 2a,w hich could regenerate 6 by ar eversible process. Although ap athway through direct nucleophilic carboxylation of 2a cannot be ruled out, [3c] we currently speculate that carboxylation would take place by CO 2 insertion into the CuÀCb ond in the alkenylcoppers pecies 6 to afford the corresponding copper carboxylate 7.F inally,t ransmetalation betweent he copperc arboxylate 7 and the dialkylzinc reagent would provide zinc carboxylate 8 regenerating alkylcopper species 5.…”

Section: Resultsmentioning

confidence: 99%

Cu‐Catalyzed Alkylative Carboxylation of Ynamides with Dialkylzinc Reagents and Carbon Dioxide

Takimoto

Gholap

Hou

2015

Chemistry A European J

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Alkylative carboxylation of ynamides with CO2 and dialkylzinc reagents using a N-heterocyclic carbene (NHC)-copper catalyst has been developed. A variety of ynamides, both cyclic and acyclic, undergo this transformation under mild conditions to afford the corresponding α,β-unsaturated carboxylic acids, which contain the α,β-dehydroamino acid skeleton. The present alkylative carboxylation formally consists of Cu-catalyzed carbozincation of ynamides with dialkylzinc reagents with the subsequent nucleophilic carboxylation of the resulting alkenylzinc species with CO2 . Dialkylzinc reagents bearing a β-hydrogen atom such as Et2 Zn and Bu2 Zn still afford the alkylated products despite the potential for β-hydride elimination. This protocol would be a desirable method for the synthesis of highly substituted α,β- dehydroamino acid derivatives due to its high regio- and stereoselectivity, simple one-pot procedure, and its use of CO2 as a starting material.

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“…Yorimitsu and Oshima reported an interesting transformation of ynamides to nitriles by a carbomagnesiation/aza-Claisen rearrangement sequence (Scheme 15) [79–80]. …”

Section: Reviewmentioning

confidence: 99%

Recent advances in transition-metal-catalyzed intermolecular carbomagnesiation and carbozincation

Murakami¹,

Yorimitsu²

2013

Beilstein J. Org. Chem.

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SummaryCarbomagnesiation and carbozincation reactions are efficient and direct routes to prepare complex and stereodefined organomagnesium and organozinc reagents. However, carbon–carbon unsaturated bonds are generally unreactive toward organomagnesium and organozinc reagents. Thus, transition metals were employed to accomplish the carbometalation involving wide varieties of substrates and reagents. Recent advances of transition-metal-catalyzed carbomagnesiation and carbozincation reactions are reviewed in this article. The contents are separated into five sections: carbomagnesiation and carbozincation of (1) alkynes bearing an electron-withdrawing group; (2) alkynes bearing a directing group; (3) strained cyclopropenes; (4) unactivated alkynes or alkenes; and (5) substrates that have two carbon–carbon unsaturated bonds (allenes, dienes, enynes, or diynes).

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Silylcupration and Copper-Catalyzed Carbomagnesiation of Ynamides: Application to Aza-Claisen Rearrangement

Cited by 46 publications

References 22 publications

Trans‐Selective Radical Silylzincation of Ynamides

Trans‐Selective Radical Silylzincation of Ynamides

Cu‐Catalyzed Alkylative Carboxylation of Ynamides with Dialkylzinc Reagents and Carbon Dioxide

Recent advances in transition-metal-catalyzed intermolecular carbomagnesiation and carbozincation

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