Copper‐Catalyzed Amination of Congested and Functionalized α‐Bromocarboxamides with either Amines or Ammonia at Room Temperature

Ishida, Syo; Takeuchi, Kentaro; Taniyama, Nobuhiro; Sunada, Yusuke; Nishikata, Takashi

doi:10.1002/anie.201706293

Cited by 40 publications

(20 citation statements)

References 59 publications

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“…A year later Nishikata et al . reported their achievements of a copper‐catalyzed amination of hindered tertiary alkyl α‐bromoamides with either amines or ammonia (top Scheme ) …”

Section: α‐Amination Of α‐Haloamidesmentioning

confidence: 99%

“…A year later Nishikata et al reported their achievements of a copper-catalyzed amination of hindered tertiary alkyl α-bromoamides with either amines or ammonia (top Scheme 42). [68] Importantly, the method allowed for the facile preparation of congested and highly functionalized α-aminoamides through CÀ N bond formation at room temperature with no overalkylation detectable when using ammonia. Interestingly, the chiral racemic α-bromoamide A coupled with (R)-phenylglycine ethyl ester B affording the corresponding aminated product C with a chiral quaternary carbon center with high diastereoselectivity (dr = 82 : 18) (bottom Scheme 42).…”

Section: α-Amination Of α-Haloamidesmentioning

confidence: 99%

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The Fascinating Chemistry of α‐Haloamides

et al. 2020

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The aim of this review is to highlight the rich chemistry of α‐haloamides originally mainly used to discover new C−N, C−O and C−S bond forming reactions, and later widely employed in C−C cross‐coupling reactions with C(sp3), C(sp2) and C(sp) coupling partners. Radical‐mediated transformations of α‐haloamides bearing a suitable located unsaturated bond has proven to be a straightforward alternative to access diverse cyclic compounds by means of either radical initiators, transition metal redox catalysis or visible light photoredox catalysis. On the other hand, cycloadditions with α‐halohydroxamate‐based azaoxyallyl cations have garnered significant attention. Moreover, in view of the important role in life and materials science of difluoroalkylated compounds, a wide range of catalysts has been developed for the efficient incorporation of difluoroacetamido moieties into activated as well as unactivated substrates.

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“…A year later Nishikata et al . reported their achievements of a copper‐catalyzed amination of hindered tertiary alkyl α‐bromoamides with either amines or ammonia (top Scheme ) …”

Section: α‐Amination Of α‐Haloamidesmentioning

confidence: 99%

Section: α-Amination Of α-Haloamidesmentioning

confidence: 99%

The Fascinating Chemistry of α‐Haloamides

et al. 2020

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“…In the course of our research on α‐bromocarbonyl compounds in the presence of a copper salt, [35, 36] we found that α‐bromocarboxamide ( 1 ) reacts with tertiary alkyl alcohol ( 2 ) as a tertiary alkyl source in the absence of copper salts to produce a highly congested ether bond (Scheme 2). We expected that the reactivity of the electrophiles would depend on the size of the three substituents on the halo‐substituted carbon atom (or the size of nucleophiles), but the corresponding product ( 3 ) was smoothly obtained with the aid of a carboxamide moiety (neighboring effect or formation of aziridinone).…”

Section: Introductionmentioning

confidence: 99%

Chemistry of Tertiary Carbon Center in the Formation of Congested C−O Ether Bonds

et al. 2020

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Nucleophilic substitutions, including SN1 and SN2, are classical and reliable reactions, but a serious drawback is their intolerance for both bulky nucleophiles and chiral tertiary alkyl electrophiles for the synthesis of a chiral quaternary carbon center. An SRN1 reaction via a radical species is another conventional method used to carry out substitution reactions of bulky nucleophiles and alkyl halides, but chiral tertiary alkyl electrophiles cannot be used. Therefore, a stereospecific nucleophilic substitution reaction using chiral tertiary alkyl electrophiles and bulky nucleophiles has not yet been well studied. In this paper, we describe the reaction of tertiary alkyl alcohols and non‐chiral or chiral α‐bromocarboxamides as a tertiary alkyl source for the formation of congested ether compounds possessing two different tertiary alkyl groups on the oxygen atom with stereoretention.

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“…Recently, we have prepared quaternary carbon centers via radical reactions by using α-bromocarbonyl compounds (a tertiary alkyl source) and olefins or heteroatoms in the presence of a copper catalyst [17][18][19]. During our studies, we found that combinations of alkynes and tertiary alkyl radicals generated from the reaction of a copper catalyst and an α-bromocarbonyl compound can undergo i) Sonogashira type couplings via an alkynyl-Cu intermediate [20], ii) cis-hydro tertiary alkylations via 1-alkenyl-Cu [21], and iii) trans-hydro tertiary alkylations via atom-transfer radical addition (ATRA) [21] (Scheme 1, i-iii).…”

Section: Introductionmentioning

confidence: 99%

Controlling alkyne reactivity by means of a copper-catalyzed radical reaction system for the synthesis of functionalized quaternary carbons

Hirata¹,

Yamane²,

Tsubaki³

et al. 2020

Beilstein J. Org. Chem.

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A terminal alkyne is one of the most useful reactants for the synthesis of alkyne and alkene derivatives. Because an alkyne undergoes addition reaction at a C–C triple bond or cross-coupling at a terminal C–H bond. Combining those reaction patterns could realize a new reaction methodology to synthesize complex molecules including C–C multiple bonds. In this report, we found that the reaction of 3 equivalents of terminal alkyne 1 (aryl substituted alkyne) and an α-bromocarbonyl compound 2 (tertiary alkyl radical precursor) undergoes tandem alkyl radical addition/Sonogashira coupling to produce 1,3-enyne compound 3 possessing a quaternary carbon in the presence of a copper catalyst. Moreover, the reaction of α-bromocarbonyl compound 2 and an alkyne 4 possessing a carboxamide moiety undergoes tandem alkyl radical addition/C–H coupling to produce indolinone derivative 5.

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Copper‐Catalyzed Amination of Congested and Functionalized α‐Bromocarboxamides with either Amines or Ammonia at Room Temperature

Cited by 40 publications

References 59 publications

The Fascinating Chemistry of α‐Haloamides

The Fascinating Chemistry of α‐Haloamides

Chemistry of Tertiary Carbon Center in the Formation of Congested C−O Ether Bonds

Controlling alkyne reactivity by means of a copper-catalyzed radical reaction system for the synthesis of functionalized quaternary carbons

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