- Practical Application of the Aqueous 'Sulfonyl-Azide-Free' (SAFE) Diazo Transfer Protocol to Less α-C-H Acidic Ketones and Esters
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The earlier described 'sulfonyl-Azide-free' ('SAFE') protocol for diazo transfer to CH-Acidic 1,3-dicarbonyl compounds (and their similarly activated congeners) has been extended to the less reactive monocarbonyl substrates, which previously required a se
- Dar'In, Dmitry,Kantin, Grigory,Krasavin, Mikhail
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p. 4284 - 4290
(2019/11/14)
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- Site-Selective Conversion of Azido Groups at Carbonyl α-Positions to Diazo Groups in Diazido and Triazido Compounds
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This paper reports on the selective conversion of alkyl azido groups at the carbonyl α-position to diazo compounds. Through β-elimination of dinitrogen, followed by hydrazone formation/decomposition, α-azidocarbonyl moieties were transformed into α-diazo carbonyl groups in one step. As these reaction conditions do not involve aryl or general alkyl azides, site-selective conversions of di- and triazides were achieved. Through this method, the successive site-selective conjugation of the triazido molecule with three different components is demonstrated.
- Yokoi, Taiki,Tanimoto, Hiroki,Ueda, Tomomi,Morimoto, Tsumoru,Kakiuchi, Kiyomi
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p. 12103 - 12121
(2018/10/09)
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- Phosphoric Acid Catalyzed [4 + 1]-Cycloannulation Reaction of ortho-Quinone Methides and Diazoketones: Catalytic, Enantioselective Access toward cis-2,3-Dihydrobenzofurans
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A highly straightforward route to enantiomerically highly enriched cis-2,3-dihydrobenzofurans has been achieved via addition of α-diazocarbonyl compounds to in situ generated o-QMs catalyzed by a chiral Br?nsted acid. This catalytic strategy provides a direct access to 2,3-dihydrobenzofurans in high yields and with up to 91:9 dr and 99:1 er at ambient temperature. Moreover, a unique phenonium-type rearrangement accounts for product formation with an inverted 2,3-substitution pattern.
- Suneja, Arun,Schneider, Christoph
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supporting information
p. 7576 - 7580
(2019/01/03)
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- Tandem Synthesis of α-Diazoketones from 1,3-Diketones
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A highly efficient synthesis of α-diazoketone was achieved by simply stirring the mixture of 1,3-diketone, TsN3, and MeNH2 in EtOH. It was a tandem reaction including a novel primary amine-catalyzed Regitz diazo transfer of 1,3-diket
- Zhang, Jianlan,Chen, Wenwen,Huang, Dayun,Zeng, Xiaobao,Wang, Xinyan,Hu, Yuefei
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p. 9171 - 9174
(2017/09/11)
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- Facile access to 2,2-disubstituted indolin-3-ones: Via a cascade Fischer indolization/Claisen rearrangement reaction
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An efficient approach for the synthesis of 2,2-disubstituted indolin-3-ones is described. From readily accessible aryl hydrazines and allyloxyketones, 2,2-disubstituted indolin-3-ones could be obtained in good to excellent yields under mild reaction condi
- Xia, Zilei,Hu, Jiadong,Gao, Yu-Qi,Yao, Qizheng,Xie, Weiqing
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supporting information
p. 7485 - 7488
(2017/07/12)
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- Radical Cation Cyclopropanations via Chromium Photooxidative Catalysis
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The chromium photocatalyzed cyclopropanation of diazo reagents with electron-rich alkenes is described. The transformation occurs under mild conditions and features specific distinctions from traditional diazo-based cyclopropanations (e.g., avoiding β-hydride elimination, chemoselectivity considerations, etc.). The reaction appears to work most effectively using chromium catalysis, and a number of decorated cyclopropanes can be accessed in generally good yields.
- Sarabia, Francisco J.,Ferreira, Eric M.
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supporting information
p. 2865 - 2868
(2017/06/07)
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- One-pot synthesis of polyfunctional pyrazoles: An easy access to α-diazoketones from arylglyoxal monohydrates and tosylhydrazine
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A new and efficient method for the generation of α-diazoketones has been developed from arylglyoxal monohydrates and tosylhydrazine at room temperature. 1,3-Dipolar cycloaddition reactions were used to constructing polyfunctional pyrazole derivatives by the reaction of generated α-diazoketones in situ with electron-deficient alkenes, quinones and coumarins in one pot. The one-dimensional molecular packing of 1H-benzo[f]indazole-4,9-dione derivatives along the c direction demonstrated a helical chain formation via N-H?O hydrogen-bonding.
- Shu, Wen-Ming,Ma, Jun-Rui,Zheng, Kai-Lu,Sun, Hui-Ying,Wang, Mei,Yang, Yan,Wu, An-Xin
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p. 9321 - 9329
(2015/03/05)
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- Rhodium(II)-catalyzed cross-coupling of diazo compounds
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Nothing left to chance: A convenient protocol for selective cross-coupling of diazo compounds for the convergent synthesis of alkenes was developed (see scheme; EDG=aryl, heteroaryl, vinyl; R=O-alkyl, aryl). The selectivity control elements were identifie
- Hansen, Joorn H.,Parr, Brendan T.,Pelphrey, Philip,Jin, Quihui,Autschbach, Jochen,Davies, Huw M. L.
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supporting information; experimental part
p. 2544 - 2548
(2011/04/27)
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- A cascade approach to pyridines from 2-Azido-2,4-dienoates and α-diazocarbonyl compounds
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A one-pot synthesis of substituted pyridines via a cascade reaction of 2-azido-2,4-dienoates with α-diazocarbonyl compounds and triphenylphosphine is reported. The process involves a Staudinger-Meyer reaction, a Wolff rearrangement, an aza-Wittig reaction, and an electrocyclic ring- closure. The procedure is general and efficient. The substrates are readily available.
- Chen, Zheng-Bo,Hong, Deng,Wang, Yan-Guang
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supporting information; experimental part
p. 903 - 905
(2009/06/20)
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- Formation of fulleroids as major products and application of solid state reaction in the functionalization of 60|fullerene by aromatic diazoketones
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The reactions of various aromatic diazoketones with [60]fullerene were investigated in solution (o-dichlorobenzene) or in the solid-state. Under all the conditions examined, the fulleroid with the methine proton located over a six-membered ring was obtain
- Nakamura, Yosuke,Inamura, Ken'ichi,Oomuro, Ryosuke,Laurenco, Richard,Tidwell, Thomas T.,Nishimura, Jun
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p. 3032 - 3038
(2007/10/03)
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- Synthesis of 2-indanones via [4 + 1] annulation reactions of (trialkylsilyl)arylketenes
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(Matrix presented) (Trialkylsilyl)arylketenes combine with (trimethylsilyl)diazomethane in a new [4 + 1] annulation process leading to 2-indanone derivatives. The (trialkylsilyl)arylketene annulation substrates are available via the photochemical Wolff rearrangement of α-silyl-α-diazo ketones, which are themselves prepared by silylation of the corresponding diazo ketones. The mechanism of the annulation reaction is proposed to involve the formation of a 2,3-bis(silyl)cyclopropanone, which is in equilibrium with an oxyallylic cation. Electrocyclic closure of this intermediate forms the new cyclopentenone ring.
- Dalton, Audra M.,Zhang, Yongjun,Davie, Christopher P.,Danheiser, Rick L.
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p. 2465 - 2468
(2007/10/03)
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- The synthesis of α-fluoroketones by 1,4-additions of mono-fluorinated enamines to Michael acceptors
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Stork enamine reactions are explored with mono-fluorinated enamines derived from α-fluoroacetophenones and pyrrolidine. The resulting enamines react under mild conditions with Michael acceptors (acrylonitrile, methyl acrylate, methyl methacrylate, methyl vinyl ketone and cyclohexenone) to generate a variety of substituted α-fluoroketones.
- Bridge, Colin F.,O'Hagan, David
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- Diazoaldehyde Chemistry. Part 1. Transdiazotization of Acylacetaldehydes in Neutral-to-Acidic Medium. A Direct Approach to the Synthesis of α-Diazo-β-oxoaldehydes
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First ever non-deformylating transdiazotization of acylacetaldehydes was achieved: the reactions of 2-azido-1-ethylpyridinium tetrafluoroborate (4) with acylacetaldehydes 3 proceeded partially without deformylation to yield 16 new α-diazo-β-oxoaldehydes 1 along with diazomethyl ketones 2, especially in the presence of NaOAc (Scheme 1, Tables 1 and 2).The product distribution was substituent-dependent and could be correlated quantitatively.This new diazotization reaction appears as an alternative, direct, and more general method for the synthesis of these diazooxoaldehydes. α-Oxocycloalkanecarbaldehydes 5 gave only traces (if any) of α-diazocycloalkanones 7, and rearrangement products 6 were isolated (Scheme 2).Mechanisms of the reactions are discussed (Schemes 4 and 5).
- Sezer, Oezkan,Anac, Olcay
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p. 2323 - 2334
(2007/10/02)
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