- Nickel- vs Palladium-Catalyzed Synthesis of Protected Phenols from Aryl Halides
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We report the nickel-catalyzed formation of alkyl and silyl ethers from aryl halides in one step. These ethers can act as precursors to phenols by reaction with Bronsted or Lewis acids or with fluoride. A combination of Ni(COD)2 and DPPF mediates the formation of tert-butyl aryl, methyl aryl, and tert-butyldimethyl silyl aryl ethers efficiently from aryl halides and sodium alkoxides or sodium siloxides under mild reaction conditions. Reactions to form the tert-butyl aryl ethers mediated by nickel complexes have lower turnover numbers than the analogous palladium-catalyzed reactions. However, reactions to form methyl aryl ethers show higher yields when catalyzed by a combination of Ni(COD)2 and BINAP than when catalyzed by BINAP or DPPF and palladium catalyst precursors. Similarly, the formation of silyl aryl ethers occurs in higher yields and under milder conditions when catalyzed by a combination Ni(COD)2 and DPPF than when catalyzed by palladium complexes. We also report improved yields from our previous results for the palladium-catalyzed conversion of aryl halides to tert-butyl aryl ethers.
- Mann, Grace,Hartwig, John F.
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- NFSI/KF mediated mild and chemoselective interconversion of aryl TBDMS ethers to their benzene sulfonate
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A one pot protocol for the transformation of aryl TBDMS ethers to corresponding benzene sulfonate esters using NFSI (N-flurobenzenesulfonimide)/KF is described. In situ generation of benzenesulfonyl fluoride directs chemoselective cleavage of aryl silyl ethers over alkyl silyl ethers. Electron withdrawing substituent's on aryl ring provided better yield than donating groups. Protecting groups and sensitive functionalities are well tolerated in this methodology. Thus, commercially available inexpensive reagents, mild reaction conditions and step economy are the advantages of this method.
- Dond, Bharat D.,Thore, Shivaji N.
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supporting information
(2020/02/06)
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- Ni-Catalyzed Reductive Cyanation of Aryl Halides and Phenol Derivatives via Transnitrilation
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Herein, we report a Ni-catalyzed reductive coupling for the synthesis of benzonitriles from aryl (pseudo)halides and an electrophilic cyanating reagent, 2-methyl-2-phenyl malononitrile (MPMN). MPMN is a bench-stable, carbon-bound electrophilic CN reagent that does not release cyanide under the reaction conditions. A variety of medicinally relevant benzonitriles can be made in good yields. Addition of NaBr to the reaction mixture allows for the use of more challenging aryl electrophiles such as aryl chlorides, tosylates, and triflates. Mechanistic investigations suggest that NaBr plays a role in facilitating oxidative addition with these substrates.
- Mills, L. Reginald,Graham, Joshua M.,Patel, Purvish,Rousseaux, Sophie A. L.
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p. 19257 - 19262
(2019/12/02)
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- Nickel-catalyzed cyanation of aryl halides and triflates using acetonitrile: Via C-CN bond cleavage assisted by 1,4-bis(trimethylsilyl)-2,3,5,6-tetramethyl-1,4-dihydropyrazine
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We developed a non-toxic cyanation reaction of various aryl halides and triflates in acetonitrile using a catalyst system of [Ni(MeCN)6](BF4)2, 1,10-phenanthroline, and 1,4-bis(trimethylsilyl)-2,3,5,6-tetramethyl-1,4-dihydropyrazine (Si-Me4-DHP). Si-Me4-DHP was found to function as a reductant for generating nickel(0) species and a silylation reagent to achieve the catalytic cyanation via C-CN bond cleavage.
- Ueda, Yohei,Tsujimoto, Nagataka,Yurino, Taiga,Tsurugi, Hayato,Mashima, Kazushi
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p. 994 - 999
(2019/02/03)
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- Selective Activation of Human Caseinolytic Protease P (ClpP)
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Caseinolytic protease P (ClpP) is the proteolytic component of the ClpXP protein degradation complex. Eukaryotic ClpP was recently found to act within the mitochondria-specific unfolded protein response (UPRmt). However, its detailed function a
- Stahl, Matthias,Korotkov, Vadim S.,Balogh, Dóra,Kick, Leonhard M.,Gersch, Malte,Pahl, Axel,Kielkowski, Pavel,Richter, Klaus,Schneider, Sabine,Sieber, Stephan A.
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supporting information
p. 14602 - 14607
(2018/09/25)
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- Synthesis of phenols and aryl silyl ethers via arylation of complementary hydroxide surrogates
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Two transition-metal-free methods to access substituted phenols via the arylation of silanols or hydrogen peroxide with diaryliodonium salts are presented. The complementary reactivity of the two nucleophiles allows synthesis of a broad range of phenols without competing aryne formation, as illustrated by the synthesis of the anesthetic Propofol. Furthermore, silyl-protected phenols can easily be obtained, which are suitable for further transformations.
- Reitti, Marcus,Gurubrahamam, Ramani,Walther, Melanie,Lindstedt, Erik,Olofsson, Berit
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p. 1785 - 1788
(2018/04/14)
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- Redox reaction between benzyl azides and aryl azides: concerted synthesis of aryl nitriles and anilines
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A unique and novel reaction between benzyl azides and aryl azides is described to synthesize aryl nitriles and anilines concurrently, which is catalyzed with a photoactivated diruthenium complex. N-Unsubstituted imines (N-H imines) are generated first from benzyl azides, followed by the hydrogen transfer reaction between N-H imines and aryl azides. A wide range of aryl nitriles and anilines were synthesized under neutral and mild reaction conditions.
- Kim, Yongjin,Rhee, Young Ho,Park, Jaiwook
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supporting information
p. 1636 - 1641
(2017/02/23)
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- Tert-Butyldimethylsilyl Amine (TBDMS-NH2): A Mild and Green Reagent for the Protection of Benzyl Alcohols, Phenols, and Carboxylic Acids under Solvent-Free Conditions
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Herein, we present the use of the tert-butyldimethylsilyl amine (TBDMS-NH2) as a silylating reagent for phenols, benzyl alcohols, and carboxylic acids. Unlike other silyl protection reactions, this reported process with TBDMS-NH2 does not involve the form
- Duczynski, Jeremy A.,Fuller, Rebecca,Stewart, Scott G.
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p. 1172 - 1179
(2016/10/13)
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- A novel oxidative transformation of alcohols to nitriles: An efficient utility of azides as a nitrogen source
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An efficient methodology to oxidize benzylic and cinnamyl alcohols to their corresponding nitriles in excellent yields has been developed. This methodology employs DDQ as an oxidant and TMSN3 as a source of nitrogen in the presence of a catalytic amount of Cu(ClO4)2·6H 2O.
- Rokade, Balaji V.,Malekar, Sanjeev K.,Prabhu, Kandikere Ramaiah
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supporting information; experimental part
p. 5506 - 5508
(2012/07/03)
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- Mild and efficient dehydration of oximes to nitriles mediated by the Burgess reagent
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Both aliphatic and aromatic aldoximes undergo dehydration to the corresponding nitriles in excellent yields by simply heating the oximes in THF with 1.5 equivalents of the Burgess reagent (methyl N-(triethylammonium-sulfonyl)carbamate,). The reaction also works well using the PEG-supported Burgess reagent and thus has considerable potential for the parallel synthesis of cyano-containing compound libraries.
- Miller,Kaufman
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p. 1169 - 1171
(2007/10/03)
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