- HFIP-mediated 2-aza-Cope rearrangement: Metal-free synthesis of α-substituted homoallylamines at ambient temperature
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An efficient metal-free strategy for the synthesis of α-substituted homoallylamine derivatives has been developed via a 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP)-promoted 2-aza-Cope rearrangement of aldimines, generated in situ by condensation of aldehydes with easily accessible 1,1-diphenylhomoallylamines. This reaction provides rapid access to α-substituted homoallylamines with excellent functional group tolerance and yields. The reaction takes place at room temperature and no chromatographic purification is required for product isolation. The synthetic utility of the current method is further demonstrated by the transformation of the obtained benzophenone ketimines into N-unprotected homoallylamines, an α-amino alcohol and an α-amino amide. This journal is
- Gadde, Karthik,Maes, Bert U. W.,Abbaspour Tehrani, Kourosch
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supporting information
p. 4067 - 4075
(2021/05/19)
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- Primary α-tertiary amine synthesis via α-C-H functionalization
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A quinone-mediated general synthetic platform for the construction of primary α-tertiary amines from abundant primary α-branched amine starting materials is described. This procedure pivots on the efficient in situ generation of reactive ketimine intermediates and subsequent reaction with carbon-centered nucleophiles such as organomagnesium and organolithium reagents, and TMSCN, creating quaternary centers. Furthermore, extension to reverse polarity photoredox catalysis enables reactivity with electrophiles, via a nucleophilic α-amino radical intermediate. This efficient, broadly applicable and scalable amine-to-amine synthetic platform was successfully applied to library and API synthesis and in the functionalization of drug molecules.
- Vasu, Dhananjayan,Fuentes de Arriba, Angel L.,Leitch, Jamie A.,De Gombert, Antoine,Dixon, Darren J.
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p. 3401 - 3407
(2019/03/21)
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- Copper-Catalyzed Umpolung of Imines through Carbon-to-Nitrogen Boryl Migration
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We report a general strategy for the catalytic umpolung of imines, which was enabled by an unprecedented 1,2-boryl carbon-to-nitrogen migration. Based on the discovery of a rearrangement of an α-borylalkylamido copper intermediate to an α-borylaminoalkyl
- Li, Zhenghua,Zhang, Liang,Nishiura, Masayoshi,Hou, Zhaomin
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p. 4388 - 4393
(2019/05/08)
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- Unprecedented Nucleophilic Additions of Highly Polar Organometallic Compounds to Imines and Nitriles Using Water as a Non-Innocent Reaction Medium
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In contrast to classic methods carried out under inert atmospheres with dry volatile organic solvents and often low temperatures, the addition of highly polar organometallic compounds to non-activated imines and nitriles proceeds quickly, efficiently, and chemoselectively with a broad range of substrates at room temperature and under air with water as the only reaction medium. Secondary amines and tertiary carbinamines are furnished in yields of up to and over 99 %. The significant solvent D/H isotope effect observed for the on-water nucleophilic additions of organolithium compounds to imines suggests that the on-water catalysis arises from proton transfer across the organic–water interface. The strong intermolecular hydrogen bonds between water molecules may play a key role in disfavoring protonolysis, which occurs extensively in other protic media such as methanol. This work lays the foundation for reshaping many fundamental s-block metal-mediated organic transformations in water.
- Dilauro, Giuseppe,Dell'Aera, Marzia,Vitale, Paola,Capriati, Vito,Perna, Filippo Maria
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supporting information
p. 10200 - 10203
(2017/08/14)
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- Anti-Markovnikov Hydroamination of Homoallylic Amines
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The development of an anti-Markovnikov-selective hydroamination of unactivated alkenes is a significant challenge in organometallic chemistry. Herein, we present the rhodium-catalyzed anti-Markovnikov-selective hydroamination of homoallylic amines. The proximal Lewis basic amine serves to promote reactivity and enforce regioselectivity through the formation of the favored metallacycle, thus over-riding the inherent reactivity of the alkene. The scope of both the amine nucleophiles and homoallylic amines that participate in the reaction is demonstrated.
- Ensign, Seth C.,Vanable, Evan P.,Kortman, Gregory D.,Weir, Lee J.,Hull, Kami L.
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supporting information
p. 13748 - 13751
(2016/01/15)
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- Alkylative Amination of Biogenic Furans through Imine-to-Azaallyl Anion Umpolung
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Starting from biogenic furfurals, an operationally simple and scalable condensation-umpolung-alkylation protocol was employed in the synthesis of racemic furfurylamines. Subsequent enzymatic kinetic resolution by ω-transaminase or lipase biocatalysts allows for the preparation of functionalized heterocyclic building blocks from biogenic base chemicals in optically pure form.
- Blume, Fabian,Albeiruty, Mhd Haitham,Deska, Jan
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p. 2093 - 2099
(2015/07/15)
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- Catalytic asymmetric aminoallylation of aldehydes: A catalytic enantioselective aza-cope rearrangement
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(Chemical Equation Presented) A condensation-rearrangement sequence forms the basis of a high-yielding route to chiral homoallylic amines from readily accessible aldehydes (see scheme). This transformation is both the first enantioselective Bronsted acid catalyzed sigmatropic rearrangement and the first example of a catalytic asymmetric aza-Cope rearrangement.
- Rueping, Magnus,Antonchick, Andrey P.
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supporting information; experimental part
p. 10090 - 10093
(2009/05/30)
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- Novel and efficient method for the allylation of carbonyl compounds and imines using triallylaluminum
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This is the first report of the use of triallylaluminum as a reagent for the allylation of carbonyl compounds and imines. The allylation of ketimines without additional metal catalyst is known so far only in the case of the Grignard reagent. Triallylaluminum is a useful alternative to provide the homoallylic amines in excellent yield upon addition to aldimines and ketimines. The significant reactivity of this reagent was confirmed by its reaction with a sterically rigid ketone such as adamantanone to provide 1-adamantyl-3-buten-1-ol in 98% yield. The chemoselectivity of triallyl-aluminum was demonstrated by using different ketoesters. It is noteworthy that triallylaluminum is prepared from allyl bromide and aluminum metal, and not from a Grignard reagent, and that the procedure is operationally simple, leading to good to excellent product yields.
- Shen, Kao-Hsien,Yao, Ching-Fa
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p. 3980 - 3983
(2007/10/03)
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- Gallium metal mediated allylation of carbonyl compounds and imines under solvent-free conditions
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Gallium metal is effective in mediating the allylation of various carbonyl compounds and imines under solvent-free conditions, with the application of sonic energy, affording the corresponding homoallylic alcohols and amines. The imines themselves were al
- Andrews, Philip C.,Peatt, Anna C.,Raston, Colin L.
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p. 243 - 248
(2007/10/03)
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