14618-59-8

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• Ferric chloride-promoted efficient and facile BOC protection of amines
• Amines are efficiently protected as their tertiary butyloxycarbonyl (BOC) derivatives under mild reaction condition when reacted with (BOC)2O in the presence of FeCl3. The present method is applicable to a variety of amines including aliphatic, aromatic, and hetero aromatic amines.
• Tasneem,Rajanna

• p. 715 - 719

  (2011)
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• A convenient transformation of N-substituted ureas into N-(t-butoxycarbonyl)amines using a copper(II) salt-lithium t-butoxide system
• Treatment of N-substituted ureas with a copper(II) reagent prepared from lithium t-butoxide and copper(II) halide led to give the corresponding N-(t-butoxycarbonyl)amines under mild conditions. On the contrary, no reaction of N,N-disubstituted ureas proce
• Yamaguchi, Jun-ichi,Shusa, Yuji,Suyama, Takayuki

• p. 8251 - 8254

  (1999)
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• Environmentally benign N-Boc protection under solvent- and catalyst-free conditions
• A practical and highly efficient method for the protection of amines to their corresponding N-Boc derivatives is reported. In the absence of any solvent and catalyst, the present strategy works well for a series of electron-deficient and electron-rich aromatic amines as well as some sterically hindered substrates. Georg Thieme Verlag Stuttgart.
• Jia, Xueshun,Huang, Qing,Li, Jian,Li, Shaoyu,Yang, Qiushi

• p. 806 - 808

  (2007)
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• A convenient coupling reaction of isocyanates with t-alcohols with catalytic amount of SmI2 in the presence of HMPA
• Treatment of isocyanates with tertiary alcohols in the presence of catalytic amount (10 mol%) of samarium diiodide and HMPA in the THF at - 78°C under mild conditions afforded the corresponding carbamates in excellent yields within a few minutes.
• Kim, Yong Hae,Park, Heui Sul

• p. 261 - 262

  (1998)
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• Hydroaminoalkylation of Allenes
• The first examples of early-transition-metal-catalyzed hydroaminoalkylation reactions of allenes are reported. Initial studies performed with secondary aminoallenes led to the identification of a suitable titanium catalyst and revealed that under the reaction conditions, the initially formed hydroaminoalkylation products undergo an unexpected titanium-catalyzed rearrangement to form the thermodynamically more stable allylamines. The assumption that this rearrangement involves a reactive allylic cation intermediate provides a simple explanation of the fact that no successful early-transition-metal-catalyzed hydroaminoalkylations of allenes have previously been reported. As a result of the generation of the corresponding cation, the titanium-catalyzed intermolecular hydroaminoalkylation of propa-1,2-diene unexpectedly gives an aminocyclopentane product formed by incorporation of two equivalents of propa-1,2-diene.
• Bielefeld, Jens,Mannhaupt, Steffen,Schmidtmann, Marc,Doye, Sven

• p. 967 - 971

  (2019)
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• Ultrasound promoted environmentally benign, highly efficient, and chemoselective N-tert-butyloxycarbonylation of amines by reusable sulfated polyborate
• The sulfated polyborate catalyzed an efficient and chemoselective N-tert-butyloxycarbonylation of amines under ultrasonic irradiation is developed. A broad substrate scope has been demonstrated for N-Boc protection of various primary/secondary amines. It allows converting several aliphatic/aryl/heteroaryl amines, amino alcohol, aminoester, and chiral amines to their N-Boc-protected derivatives under solvent-free conditions with excellent yields. The protocol has several advantages such as easy catalyst, and product isolation, short reaction time, excellent yields, outstanding chemoselectivity, and catalyst recyclability, among others. This makes the process practicable, economical, and environmentally benign.
• Pise, Ashok S.,Ingale, Ajit P.,Dalvi, Navnath R.
• supporting information

  p. 3768 - 3780

  (2021/10/26)
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• Sulfated tungstate: A highly efficient, recyclable and ecofriendly catalyst for chemoselective N-tert butyloxycarbonylation of amines under the solvent-free conditions
• Sulfated tungstate catalyzed an efficient and ecofriendly protocol has been described for the chemoselective N-tert-butyloxycarbonylation of amines under the solvent-free conditions at room temperature. The variety of functionalized aliphatic, aromatic and heteroaromatic amines efficiently undergoes the N-tert-butyloxycarbonylation under the developed protocol. The aminoalcohol, aminophenol, aminoester as well as various chiral amines underwent the chemoselective N-Boc protection under the optimized reaction condition. The rapid reaction rate, mild conditions, very good functional group tolerance, excellent yield, solvent-free, easy recovery products and excellent catalyst recyclability are the advantages of this protocol. This makes the protocol feasible, economical and environmentally benign.
• Ingale, Ajit P.,Shinde, Sandeep V.,Thorat, Nitin M.
• supporting information

  p. 2528 - 2543

  (2021/07/02)
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• Nanoceria as an efficient and green catalyst for the chemoselective N-tert-butyloxycarbonylation of amines under the solvent-free conditions
• Nanocerium oxide mediated an efficient and green protocol has been described for the chemoselective N-tert-butyloxycarbonylation of amines under the solvent-free conditions at ambient temperature. Various aliphatic, aromatic and heteroaromatic amines were protected using developed protocol and several functional groups such as alcohol, phenol and ester were well tolerated under these conditions. The rapid reaction rate, mild conditions, very good functional group tolerance, excellent yield, solvent-free, easy recovery products and excellent catalyst recyclability are the advantages of this protocol. This makes the protocol feasible, economical and environmentally benign.
• Garad, Dnyaneshwar N.,Ingale, Ajit P.,Shinde, Sandeep V.,Ukale, Dattatraya
• supporting information

  p. 1656 - 1668

  (2021/04/05)
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• Thiamine hydrochloride as a recyclable organocatalyst for the efficient and chemoselective N-tert-butyloxycarbonylation of amines
• Thiamin hydrochloride promoted highly efficient and ecofriendly approach has been described for the chemoselective N-tert-butyloxycarbonylation of amines under solvent-free conditions at ambient temperature. The demonstrated approach has been applicable for the N-Boc protection of variety of aliphatic, aryl, heteroaryl amines. The chemoselective protection of amino group occurs in chiral amines and amino alcohol without racemization in high yield. Thiamin hydrochloride is stable, economical, easy to handle and environmentally friendly.
• Ingale, Ajit P.,Garad, Dnyaneshwar N.,Ukale, Dattatraya,Thorat, Nitin M.,Shinde, Sandeep V.
• supporting information

  p. 3791 - 3804

  (2021/11/04)
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• Organic/inorganic Fe3O4@MCM-41@Zr-piperazine: An impressive magnetite nanocatalyst for N-Tert-Butoxycarbonylation of amines
• Fe3O4@MCM-41@Zirconium magnetic nanoparticles modified with piperazine (Fe3O4@MCM-41@Zr-piperazine), as a newly reported catalyst, shows excellent catalytic activity in N-tertbutoxycarbonylation of amines under the mild and solvent-free conditions. Accordingly, different derivatives of N-tert-butylcarbamates owning diverse aliphatic, aromatic and heteroaromatic amines were prepared efficiently. Good performance of this method for the majority of used complex or acidsensitive substrates and facile separation of this nanocatalyst due to its superparamagnetic nature from the reaction mixture via an external magnetic field for several times are the most important striking features of this protocol.
• Pourhasan-Kisomi, Reyhaneh,Shirini, Farhad,Golshekan, Mostafa

• p. 3859 - 3870

  (2019/05/08)
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• Aryltrifluoromethylative cyclization of unactivated alkenes by the use of PhICF3Cl under catalyst-free conditions
• A concise and catalyst-free aryltrifluoromethylative cyclization of unactivated alkenes has been developed herein. The use of PhICF3Cl as a powerful trifluoromethylating agent allows easy transformations. A set of trifluoroethylated carbocycles and aza-hereocycles were efficiently synthesized in good yield and selectivity. A broad substrate scope, mild reaction conditions, and easy operation would make this method well-suited for applications.
• Guo, Jia,Xu, Cong,Liu, Xiaowei,Wang, Mang
• supporting information

  p. 2162 - 2168

  (2019/02/27)
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• Au(i)/Au(iii)-Catalyzed C-N coupling
• Cycling between Au(i) and Au(iii) is challenging, so gold-catalyzed cross-couplings are rare. The (MeDalphos)AuCl complex, which we showed was prone to undergo oxidative addition, is reported here to efficiently catalyze the C-N coupling of aryl iodides and amines. The transformation does not require an external oxidant or a directing group. It is robust and works with a wide scope of aryl iodides and N-nucleophiles under mild conditions. Mechanistic studies, including the NMR and MS characterization of a key aryl amido Au(iii) complex, strongly support a 2e redox cycle in which oxidative addition precedes transmetalation and reductive elimination is the rate-determining step.
• Rodriguez, Jessica,Adet, Nicolas,Saffon-Merceron, Nathalie,Bourissou, Didier
• supporting information

  p. 94 - 97

  (2019/12/25)
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• Tert-Butyl(3-cyano-4,6-dimethylpyridin-2-yl)carbonate as a green and chemoselective N-tert-butoxycarbonylation reagent
• The use of tert-butyl(3-cyano-4,6-dimethylpyridin-2-yl)carbonate as a chemoselective tert-butoxycarbonylation reagent for aromatic and aliphatic amines has been demonstrated. To gain insight into this reaction, in situ React IR technology was used to confirm the effectivity and chemoselectivity of this novel Boc reagent. The reaction was carried out chemoselectively in high yield under mild, environment-friendly conditions and was completed quickly within 1 hour. Simultaneously, the Boc carrier was easily recyclable, and has great application prospects for industrial production.
• Du, Fangyu,Zhou, Qifan,Fu, Yang,Zhao, Hanqi,Chen, Yuanguang,Chen, Guoliang
• supporting information

  p. 6549 - 6554

  (2019/05/04)
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• A new bifunctional heterogeneous nanocatalyst for one-pot reduction-Schiff base condensation and reduction-carbonylation of nitroarenes
• In this work, synthesis of Pd-NHC-γ-Fe2O3-n-butyl-SO3H and its activity as a bifunctional heterogeneous nanocatalyst containing Pd-NHC and acidic functional groups, are described. This newly synthesized nanomagnetic catalyst is fully characterized by different methods such as FT-IR, XPS, TEM, VSM, ICP and TG analysis. At first, the catalytic activity of Pd-NHC-γ-Fe2O3-n-butyl-SO3H is evaluated for the reduction of nitroarenes in aqueous media using NaBH4 as a clean source of hydrogen generation at ambient temperature. Using the promising results obtained from the nitroarene reduction, this catalytic system is used for two one-pot protocols including reduction-Schiff base condensation and reduction-carbonylation of various nitroarenes. In these reactions the in situ formed amines are further reacted with aldehydes to yield imines or carbonylated to amides. The desired products are obtained in good to high yields in the presence of Pd-NHC-γ-Fe2O3-n-butyl-SO3H as a bifunctional catalyst. The catalyst is reused with the aid of a magnetic bar for up to six consecutive cycles without any drastic loss of its catalytic activity.
• Sobhani, Sara,Chahkamali, Farhad Omarzehi,Sansano, José Miguel

• p. 1362 - 1372

  (2019/01/24)
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• Chemoselective: N-tert -butyloxycarbonylation of amines in glycerol
• A catalyst-free, efficient and green protocol has been developed for the chemoselective N-Boc protection of amines by using glycerol as a solvent at room temperature. A variety of functionalized amines, such as aliphatic, aromatic as well as heteroaromatic were protected using the developed protocol. N-tert-Butyloxycarbonylation derivatives were formed without the formation of isocyanate, urea, N,N-di-t-Boc, or oxazolidinone as side products. The operational simplicity, cleaner reaction, rapid reaction convergence, functional group tolerance, excellent yield, high selectivity, catalyst-free feature and solvent recyclability are the distinct advantages of this protocol. Owing to these merits, this protocol is feasible, economical and environmentally benign.
• Ingale, Ajit P.,More, Vishal K.,Gangarde, Uddhav S.,Shinde, Sandeep V.
• supporting information

  p. 10142 - 10147

  (2018/06/18)
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• Harnessing Cascade Suzuki-Cyclization Reactions of Pyrazolo[3,4-b]pyridine for the Synthesis of Tetracyclic Fused Heteroaromatics
• Numerous procedures have been described for the functionalization of pyrazolo[3,4-b]pyridine, mainly involving nucleophilic substitutions at the C-4 position or esterifications/amidations at the C-5 position. In this paper, we describe a robust, easy to implement protocol for the Suzuki cross-coupling reaction of chloroarene 2, followed by in-situ lactonization to provide chromenopyrazolopyridines. The extension of the scope of the reaction to fused naphthyridinones is also reported. This strategy gave access to 10 original pyrazolopyridine-containing tetracyclic compounds.
• Lavrard, Hubert,Popowycz, Florence
• supporting information

  p. 600 - 608

  (2017/02/05)
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• Sustainable and chemoselective N-Boc protection of amines in biodegradable deep eutectic solvent
• Abstract: A green and practical approach for the chemoselective N-tert-butyloxycarbonylation of structurally diverse amines with di-tert-butyl dicarbonate (Boc2O) is described. Selective N-Boc protection was achieved in excellent yields in urea-choline chloride deep eutectic solvent (DES) as the most promising environmentally benign and cost-effective solvent under mild reaction condition. DES can protect various aromatic and aliphatic amines using Boc2O in good to excellent yields in short reaction times without any side products. Graphical abstract: [Figure not available: see fulltext.].
• Azizi, Najmedin,Shirdel, Fatemeh

• p. 1069 - 1074

  (2017/05/12)
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• Copper nanoparticles catalyzed N-H functionalization: An efficient solvent-free N-tert-butyloxycarbonylation strategy
• A chemoselective transformation of amines to their tert-butyloxycarbonyl (Boc) protected derivatives (NBoc) is described using Cu-NPs under solvent-free conditions. Simple method, rapid reaction rate, mild conditions, tolerance of a wide range of functional groups, excellent yield, ease recovery and high catalytic turnover are the salient features of this approach. tert-Butyloxycarbonylation of chiral amino acid esters and amino alcohols were performed without racemization.
• Deb, Barnali,Debnath, Sudipto,Deb, Anindita,Maiti, Dilip K.,Majumdar, Swapan
• supporting information

  p. 629 - 633

  (2017/01/25)
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• Preparation, characterization and application of 1,4-disulfopiperazine-1,4-diium chloride ([Piper-(SO3H)2]·2Cl) as an efficient dicationic ionic catalyst for the N-Boc protection of amines
• In this work, 1,4-disulfopiperazine-1,4-diium chloride ([Piper-(SO3H)2]·2Cl), as a novel Br?nsted acidic ionic catalyst is synthesized and characterized using a series of techniques including FT-IR, TGA, DTA, SEM, pH analysis and Hammett acidity function. This substance can significantly catalyze the N-Boc protection of amines without solvent interference at room temperature. The advantages of this manner are chemoselectivity, short reaction times, suitable yields, excellent yields of the products, without solvent interference and ease of preparation as well as reusability of the catalyst.
• Koodehi, Tahereh Ghauri,Shirini, Farhad,Goli-Jolodar, Omid

• p. 443 - 456

  (2017/01/10)
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• Heterobimetallic dinuclear lanthanide alkoxide complexes as acid-base bifunctional catalysts for synthesis of carbamates under solvent-free conditions
• Heterobimetallic dinuclear lanthanide alkoxide complexes Ln2Na8(OCH2CH2NMe2)12(OH)2 [Ln: I (Nd), II (Sm), III (Yb) and IV (Y)] were used as efficient acid-base bifunctional catalysts for the synthesis of carbamates from dialkyl carbonates and amines as well as the N-Boc protection of amines. The cooperative catalysts showed high catalytic activity and a wide scope of substrates with good to excellent yields under solvent-free conditions. The systems have shown higher catalytic activities due to the noteworthy synergistic interactions of Lewis acid center-Br?nsted basic center. The comparison of catalytic efficiency between mono- and dinuclear heterobimetallic lanthanide alkoxide analogues was also investigated.
• Zeng, Ruijie,Bao, Linquan,Sheng, Hongting,Sun, Lili,Chen, Man,Feng, Yan,Zhu, Manzhou

• p. 78576 - 78584

  (2016/09/09)
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• Pd(II)/Ag(I)-Promoted One-Pot Synthesis of Cyclic Ureas from (Hetero)Aromatic Amines and Isocyanates
• A simple and facile one-pot reaction has been developed to afford a diverse range of N,N′-disubstituted benzimidazolones and imidazopyridinones containing two differently substituted N atoms. A cooperative Pd(II)/Ag(I) system promotes the sequential addition/intramolecular C-H amidation reaction of (hetero)aromatic amines and isocyanates, leading to the formation of two C-N bonds. A mechanism involving radical intermediates generated by single-electron transfer (SET) in the presence of a Ag2CO3 oxidant and Pd(OAc)2 Lewis acid is proposed. This protocol offers an operationally easy, simple, and robust approach with the use of readily available starting materials, good functional group tolerance, and high efficiency.
• Youn, So Won,Kim, Yi Hyun
• supporting information

  p. 6140 - 6143

  (2016/12/09)
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• Palladium-Catalyzed Decarboxylative Synthesis of Arylamines
• A novel approach has been developed for the synthesis of arylamines via the palladium-catalyzed intramolecular decarboxylative coupling (IDC) of aroyloxycarbamates, obtained in situ by reacting aryl carboxylic acids with hydroxycarbamates. The reaction offers facile access to structurally diverse arylamines with the site-specific formation of the C(sp2)-N bond under mild conditions.
• Dai, Qipu,Li, Peihe,Ma, Nuannuan,Hu, Changwen

• p. 5560 - 5563

  (2016/11/17)
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• Palladium-catalyzed oxidative carbonylation of aromatic C-H bonds of N -alkylanilines with CO and alcohols for the synthesis of o -aminobenzoates
• A Pd(II)-catalyzed C-H monocarbonylation of N-alkylanilines for the synthesis of o-aminobenzoates has been developed. Various aliphatic alcohols and phenol were tolerated in the reaction to afford the corresponding o-aminobenzoates in good yields under mild balloon pressure of CO.
• Chen, Ming,Ren, Zhi-Hui,Wang, Yao-Yu,Guan, Zheng-Hui

• p. 1258 - 1263

  (2015/01/30)
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• Aqueous MW eco-friendly protocol for amino group protection
• In this paper a new catalyst-free and on-water method for protection of amines and amino acids with di-tert-butyl dicarbonate, 9-fluorenylmethoxycarbonyl chloride, acetyl chloride and tosyl chloride is presented. The protection can be realized in a few minutes under microwave-assistance. The reaction proved to be chemoselective in presence of ambident nucleophiles and water solution of di-tert-butyl carboxylic acid or chloride acid are the only wastes produced.
• Nardi,Cano, N. Herrera,Costanzo,Oliverio,Sindona,Procopio

• p. 18751 - 18760

  (2015/06/15)
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• Preparation, characterization and application of succinimidinium hydrogensulfate ([H-Suc]HSO4) as an efficient ionic liquid catalyst for the N-Boc protection of amines
• In this work, succinimidinium hydrogensulfate ([H-Suc]HSO4), as a novel Bronsted acidic ionic liquid is prepared and characterized by studying its FT-IR, 1H NMR, 13C NMR, mass and SEM. This reagent can be used as an efficient catalyst for the N-Boc protection of amines at room temperature and neat conditions. This new method consistently has the advantages of excellent yields and short reaction times. Further, this ionic liquid can be recovered and reused for several times. This journal is
• Shirini, Farhad,Jolodar, Omid Goli,Seddighi, Mohadeseh,Borujeni, Hojatollah Takbiri

• p. 19790 - 19798

  (2015/03/18)
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• A palladium catalyst supported on carbon-coated cobalt nanoparticles-preparation of palladium-free biaryls by suzuki-miyaura reactions in ethanol
• The preparation of a heterogeneous Pd catalyst supported on carbon-coated magnetic nanoparticles (NPs) bearing 4-(diphenylphosphinomethyl)phenyl groups is discussed. These NPs were initially prepared by chemical vapour deposition (CVD) of carbon on prefor
• Derible, Antoine,Diebold, Carine,Dentzer, Joseph,Gadiou, Roger,Becht, Jean-Michel,Le Drian, Claude

• p. 7699 - 7706

  (2015/04/22)
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• General solvent-free highly selective N-tert-butyloxycarbonylation strategy using protic ionic liquid as an efficient catalyst
• A simple, rapid and solvent-free protocol is described for the chemo-selective transformation of amines to tert-butyloxycarbonyl protected derivatives (NHBoc) using Boc2O and imidazolium trifluoroacetate protic ionic liquid (5-20 mol%). Unwanted side products such as isocyanate, urea or N,N-di-Boc were not detected. The scope of the protection strategy was successfully explored for substrate alcohols, phenols and thiol at elevated temperatures. Optically pure amino acids, amino acid esters and amino alcohols were efficiently converted to the corresponding N-Boc protected derivatives in excellent yields without racemization at the chiral center. The distinct advantages of this method are: operational simplicity, cleaner reaction, high selectivity, excellent yield, rapid reaction convergence, easy preparation and recyclability of the catalyst.
• Majumdar, Swapan,De, Jhinuk,Chakraborty, Ankita,Maiti, Dilip K.

• p. 24544 - 24550

  (2014/07/07)
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• N-Protection of amines using pyridinium 2,2,2-trifluoroacetate ionic liquid as an efficient and reusable catalyst
• A simple, green, and efficient method for the N-tert-butoxycarbonylation of amines by pyridinium 2,2,2-trifluoroacetate ([Py][OTf]) as an efficient and reusable catalyst is reported. In general, electron donating groups on aryl group give rise to the higher yields than electron withdrawing groups. Clean reaction, short reaction times, high yields, reusability of catalyst, and easy preparation of it are some advantages of this work.
• Karimian, Somaye,Tajik, Hassan

• p. 218 - 220

  (2014/02/14)
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• A 2,6-bis(phenylamino)pyridinato titanium catalyst for the highly regioselective hydroaminoalkylation of styrenes and 1,3-butadienes
• The C-C bond forming catalytic hydroaminoalkylation of terminal alkenes, 1,3-dienes, or styrenes allows a direct and highly atom efficient (100 %) synthesis of amines which can result in the formation of two regioisomers, the linear and the branched product. We present a new titanium catalyst with 2,6-bis(phenylamino)pyridinato ligands for intermolecular hydroaminoalkylation reactions of styrenes and 1-phenyl-1,3-butadienes that delivers the corresponding linear hydroaminoalkylation products with excellent regioselectivities. Linear progress: A new Ti complex with 2,6-bis(phenylamino) pyridinato ligands catalyzes highly regioselective hydroaminoalkylation reactions of styrenes. The process that directly gives access to the corresponding linear hydroaminoalkylation products offers a new and flexible synthetic approach towards pharmaceutically important 3-arylpropylamines. It is also possible to convert (E)-1-phenyl-1,3-butadienes into the corresponding linear products.
• Doerfler, Jaika,Preuss, Till,Schischko, Alexandra,Schmidtmann, Marc,Doye, Sven
• supporting information

  p. 7918 - 7922

  (2014/08/05)
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• A mild, copper-catalysed amide deprotection strategy: Use of tert-butyl as a protecting group
• Mild methods for the deprotection of organic substrates are of fundamental importance in synthetic chemistry. A new room temperature method using a catalytic amount of Cu(OTf)2is reported. This allows use of the tert-butyl group as an amide protecting group. The methodology is also extended to Boc-deprotection.
• Evans, Vikki,Mahon, Mary F.,Webster, Ruth L.
• supporting information

  p. 7593 - 7597

  (2014/12/10)
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• Metal free oxidative coupling of aryl formamides with alcohols for the synthesis of carbamates
• A direct transformation of N-aryl formamides to the corresponding carbamates via the formation of isocyanate intermediates is achieved in good yields using hypervalent iodine as an oxidant. This journal is
• Reddy, N. Veera,Prasad, K. Rajendra,Reddy, P. Sudhir,Lakshmi Kantam,Reddy, K. Rajender

• p. 2172 - 2175

  (2014/04/03)
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• Silver-catalyzed incorporation of carbon dioxide into o-alkynylaniline derivatives
• Benzoxazine-2-one derivatives are important heterocycle structures because of their various pharmaceutical activities, though their synthetic methods had been limited. In some cases, toxic reagents, such as phosgene or carbon monoxide, are required. It was found that a silver catalyst successfully promoted the incorporation of CO2 into o-alkynylanilines to afford the corresponding benzoxazine-2-ones bearing Z exo-olefin via 6-exo-dig cyclization at the activated C-C triple bond.
• Ishida, Tomonobu,Kikuchi, Satoshi,Tsubo, Tatsuyuki,Yamada, Tohru
• supporting information

  p. 848 - 851

  (2013/03/28)
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• Iron(III)triflate as a highly efficient, recyclable and green catalyst for the N-Boc protection of amines
• Iron (III) triflate was used as an efficient catalyst for N-t-butoxycarbonylation of amines with di-t-butyl dicarbonate under solvent-free conditions at room temperature. Various aliphatic, aromatic, heterocyclic amines and aminols were protected as their corresponding mono-carbamates in excellent yields and short reaction times. Only two of the 23 monocarbamates were new. No competitive side reactions such as isocyanate, urea, nor N,N-di-Boc formation were observed. The reported method is mild and has the advantages of low cost, chemoselectivity and, because no solvent is used and the catalyst can be recycled, it is classifiable as a green procedure.
• Feng, Chengliang,Chu, Ningning,Zhang, Shuguang,Cai, Jin,Chen, Junqing,Hu, Huayou,Ji, Min

• p. 757 - 760

  (2014/01/23)
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• Synthesis, characterization and catalytic properties of monodispersed nano-sphere silica sulfuric acid
• In this research, the first report on synthesis of nano-sphere silica sulfuric acid (NS-SSA) as new catalyst was reported. The catalyst was prepared by the reaction of nano-sphere silica with chlorosulfonic acid at room temperature. The catalyst has been identified using various techniques (XRD, SEM, TEM, EDX, TGA, FT-IR) and results were shown that it was a spherical shape and its particle size was between 60 and 90 nm. The catalyst can be easily recovered and reused for seventeen reaction cycles for protection of amines without considerable loss of activity. It was found that the catalyst can be efficiently in large scale and we examined some reactions in scales of 50 and 100 mmol. Also, this method has some advantages such as high TOF of catalyst, chemoselectivity, easy work-up and short reaction time.
• Zolfigol,Khazaei,Mokhlesi,Derakhshan-Panah

• p. 111 - 116

  (2013/04/23)
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• 1,3-Disulfonic acid imidazolium hydrogen sulfate as an efficient and reusable ionic liquid catalyst for the N-Boc protection of amines
• 1,3-Disulfonic acid imidazolium hydrogen sulfate is easily prepared and used as an efficient and recyclable ionic liquid for the N-Boc protection of amines at room temperature and neat conditions. This new method consistently has the advantages of excellent yields and short reaction times. Further, the catalyst can be reused and recovered for several times without loss of activity.
• Shirini, Farhad,Khaligh, Nader Ghaffari

• p. 386 - 393

  (2013/03/14)
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• N-sulfonic acid poly(4-vinylpyridinium) chloride: An efficient and reusable solid acid catalyst in N-Boc protection of amines
• N-sulfonic acid poly(4-vinylpyridinium) chloride is easily prepared by the reaction of poly(4-vinylpyridine) with neat chlorosulfonic acid. This reagent can be used as an efficient catalyst for the N-Boc protection of amines at room temperature and neat conditions. This new method consistently has the advantages of excellent yields and short reaction times. Further, the catalyst can be reused and recovered for several times.
• Shirini, Farhad,Khaligh, Nader Ghaffari,Jolodar, Omid Goli

• p. 181 - 188

  (2013/07/26)
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• Ionic liquid (tetrachlorocobaltate(II) anion with a dicationic counterion) catalyzed N-Boc protection of amines
• Ionic liquid (1,1′-hexane-1,6-diylbis(3-methylpyridinium) tetrachlorocobaltate(II) ([C6(mpy)2][CoCl 4]2-)) catalyzed N-tert-butyloxycarbonylation (N-Boc) of various amines using (Boc)2O is reported. Halogenated aniline and amino alcohols were converted efficiently to their corresponding N-Boc derivatives without any side products. The reported method is mild, solvent free, uses low amounts of ionic liquid, allows easy product separation and results in high yields of the products. The catalytic efficiency for N-Boc formation in IL is superior to previously reported catalysts.
• Chinnappan, Amutha,La, Dahye,Kim, Hern

• p. 13324 - 13328

  (2013/09/02)
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• Nanocrystalline titania-based sulfonic acid (TiO2-Pr-SO 3H) as a new, highly efficient and recyclable solid acid catalyst for the N-Boc protection of amines at room temperature
• Sulfonic acid-functionalized nanoporous titania (TiO2-Pr-SO 3H) was prepared from the reaction of (3-mercaptopropyl) trimethoxysilane and TiO2, then by oxidation of thiols group with hydrogen peroxide. The morphology and acidity of synthesized catalyst was characterized by FT-IR, SEM, TEM, TGA and XRD techniques and Hammett acidity test. The catalytic performance of TiO2-Pr-SO3H was investigated in the N-tert-butoxycarbonylation of amines under solvent-free conditions at room temperature. Our novel method is mild, chemoselective and has the advantages such as heterogeneous catalysis, low cost and the recyclability of the catalyst.
• Atghia,Sarvi Beigbaghlou

• p. 42 - 49

  (2013/10/01)
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• Microwave assisted mild, rapid, solvent-less, and catalyst-free chemoselective N-tert-butyloxycarbonylation of amines
• Microwave assisted simple, rapid, solventless, and catalyst-free chemoselective method for the protection of amino group in aromatic, aliphatic, heterocyclic, aralkyl amines, phenyl hydrazine, and amino acid esters in good to excellent isolated yield (83-98%) in short reaction time (2-12 min) has been reported.
• Dighe, Satish N.,Jadhav, Hemant R.

• p. 5803 - 5806

  (2012/10/29)
• 

• Simple and efficient method for n-boc protection of amines using PEG-400 as a reaction medium under mild conditions
• Simple and efficient method for N-Boc protection of amines using PEG-400 as an ecofriendly reaction medium at room temperature is described. Various aromatic, heteroaromatic, and aliphatic amines were converted to the corresponding N-tert-butyl-carbamates in good to excellent yields in short times.
• Zeng, Hongyao,Li, Yongjia,Shao, Huawu
• experimental part

  p. 25 - 32

  (2011/10/19)
• 

• Succinimide sulfonic acid (SuSA): An efficient and recyclable catalyst for the chemoselective N-Boc protection of amines
• Succinimide sulfonic acid (SuSA) as a stable reagent is easily prepared by the reaction of succinimide with neat chlorosulfonic acid. This compound is able to catalyze the chemoselective conversion of amines to their corresponding N-Boc protected derivatives with (Boc)2O. All reactions were performed under mild conditions, giving the desired products in good to high yields. Springer-Verlag 2011.
• Shirini, Farhad,Khaligh, Nader Ghaffari
• experimental part

  p. 631 - 635

  (2012/07/03)
• 

• Poly(4-vinylpyridine) catalyzed chemoselective O-TMS protection of alcohols and phenols and N-Boc protection of amines
• Poly(4-vinylpyridine) (PVP) acts as an efficient and reusable catalyst for the selective and efficient trimethylsilylation of alcohols and phenols with hexamethyldisilazane (HMDS) and N-tert-butoxycarbonylation of amines with (Boc)2O. All reactions were performed under mild conditions in good to high yields. Iranian Chemical Society 2012.
• Shirini, Farhad,Khaligh, Nader Ghaffari

• p. 495 - 502

  (2013/02/22)
• 

• Zinc chloride promoted efficient and facile BOC protection of amines
• Amines are efficiently protected as their BOC derivatives under mild reaction conditions when reacted with BOC anhydride in presence of ZnCl2. The present method is applicable to a variety of amines including aliphatic, aromatic as well as heteroaromatic amines. This protocol appears to be competitive and in some cases superior to previously reported procedures that work under basic conditions.
• Arifuddin, M.,Lakshmikant, N.,Rajasekar, N.,Shinde, D. B.

• p. 1168 - 1172,5

  (2020/08/31)
• 

• (Tosylimino)phenyl-λ3-iodane as a reagent for the synthesis of methyl carbamates via hofmann rearrangement of aromatic and aliphatic carboxamides
• A new, mild procedure for the Hofmann rearrangement of aromatic and aliphatic carboxamides using (tosylimino)phenyl-λ3-iodane, PhINTs, as a reagent is reported. Because of the mild reaction conditions, this method is particularly useful for the Hofmann rearrangement of substituted benzamides, which usually afford complex reaction mixtures with other hypervalent iodine oxidants. The mild reaction conditions and high selectivity in the reaction of carboxamides with PhINTs allow the isolation of the initially formed labile isocyanates or their subsequent conversion to stable carbamates by treatment with alcohols.
• Yoshimura, Akira,Luedtke, Matthew W.,Zhdankin, Viktor V.

• p. 2087 - 2091

  (2012/05/05)
• 

• Palladium-catalyzed amidation of aryl halides using 2-dialkylphosphino- 2′-alkoxyl-1,1′-binaphthyl as ligands
• Palladium-catalyzed intermolecular C-N bond-forming reactions between aryl halides and amides are described using 2-dialkylphosphino-2′-alkoxyl-1, 1′-binaphthyl, which is both bulky and electron-rich, as the ligand. A variety of amides, including aliphatic and aromatic primary amides, lactams, and carbamates, were viable substrates for the amidation, which exhibited good functional group compatibility. By tuning the substituents at the 2,2′-position of 1,1′-binaphthyl of the ligand, the palladium-catalyzed amidation of bulky aryl halides was realized and this coupling reaction was used to synthesize 2-amino-2′-methoxy-1,1′- binaphthyl in high yield.
• Ma, Fangfang,Xie, Xiaomin,Zhang, Lei,Peng, Zhiyong,Ding, Lina,Fu, Lei,Zhang, Zhaoguo
• experimental part

  p. 5279 - 5285

  (2012/08/07)
• 

• Guanidine hydrochloride as an organocatalyst for N-Boc protection of amino groups
• A simple and efficient method for the chemoselective N-Boc protection of the amine moiety in a variety of compounds is described using di-tert-butyl dicarbonate and guanidine hydrochloride as an organocatalyst in ethanol at 35-40°C. Selective mono-N-Boc protection of diamines and chemoselective protection of hydroxylamines without formation of any side products is achieved. Amino acids and peptides are N-Boc protected efficiently in excellent yields under convenient reaction conditions.
• Jahani, Fatemeh,Tajbakhsh, Mahmood,Golchoubian, Hamid,Khaksar, Samad
• supporting information; experimental part

  p. 1260 - 1264

  (2011/04/15)
• 

• Nonsolvent application of ionic liquids: Organo-catalysis by 1-alkyl-3-methylimidazolium cation based room-temperature ionic liquids for chemoselective N-tert-butyloxycarbonylation of amines and the influence of the C-2 hydrogen on catalytic efficiency
• 1-Alkyl-3-methylimidazolium cation based ionic liquids efficiently catalyze N-tert-butyloxycarbonylation of amines with excellent chemoselectivity. The catalytic role of the ionic liquid is envisaged as "electrophilic activation" of di-tert-butyl dicarbonate (Boc2O) through bifurcated hydrogen bond formation with the C-2 hydrogen of the 1-alkyl-3-methylimidazolium cation and has been supported by a downfield shift of the imidazolium C-2 hydrogen of 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([bmim][NTf2]) from δ 8.39 to 8.66 in the presence of Boc2O in the 1H NMR and a drastic reduction of the catalytic efficiency with 1-butyl-2,3-dimethylimidazolium ionic liquids that are devoid of the C-2 hydrogen. The differential time required for reaction with aromatic and aliphatic amines has offered means for selective N-t-Boc formation during inter and intramolecular competitions. Preferential N-t-Boc formation with secondary aliphatic amine has been achieved in the presence of primary aliphatic amine. Comparison of the catalytic efficiency for N-t-Boc formation with a common substrate revealed that [bmim][NTf2] is superior to the reported Lewis acid catalysts.
• Sarkar, Anirban,Roy, Sudipta Raha,Parikh, Naisargee,Chakraborti, Asit K.
• experimental part

  p. 7132 - 7140

  (2011/10/08)
• 

• Sulfonic acid-functionalized ordered nanoporous Na+- montmorillonite (SANM): A novel, efficient and recyclable catalyst for the chemoselective N-Boc protection of amines in solventless media
• Sulfonic acid-functionalized ordered nanoporous Na+- montmorillonite (SANM) was used as an efficient catalyst for N-tert-butoxycarbonylation of amines with di-tert-butyl dicarbonate under solvent-free conditions at room temperature. Various aliphatic, aromatic, heterocyclic amines and aminols were protected as their corresponding mono-carbamates in excellent yields and short reaction times. No competitive side reactions such as isocyanate, urea, and N,N-di-Boc formation were observed. The reported method is mild, chemoselective and has the advantages such as heterogeneous catalysis, low cost and the recyclability of the catalyst.
• Shirini, Farhad,Mamaghani, Manouchehr,Atghia, Seyyed Vahid
• experimental part

  p. 1088 - 1094

  (2012/01/15)
• 

• PEG-mediated facile protocol for N-Boc protection of amines
• We have reported an efficient and eco-friendly protocol for the protection of various structurally and electronically divergent aryl and aliphatic amines using (Boc)2O in the presence of PEG-400 at room temperature. The reaction gave excellent
• Siddaiah,Basha,Padma Rao,Viplava Prasad,Suryachendra Rao
• experimental part

  p. 1127 - 1129

  (2011/02/28)
• 

• An expeditious, efficient green methodology for the Boc protection of amines and silyl protection of alcohols over tungstophosphoric acid-doped mesoporous silica
• An efficient, chemoselective and eco-friendly protocol for the protection of amines as N-tert-butylcarbamate using (Boc)2O and protection of alcohols as silyl ether using HMDS over tungstophosphoric acid/SBA15 has been developed. Solventless condition, easy work-up, short reaction time, excellent yields and reusability of the catalyst are the striking features of this methodology which can be considered to be one of the better methods for the protection of amines and alcohols.
• Karmakar, Bikash,Banerji, Julie
• experimental part

  p. 3855 - 3858

  (2010/08/20)
• 

• Saccharin sulfonic acid catalyzed N-Boc protection of amines and formation of tertbutyl ethers from alcohols
• Saccharin sulfonic acid (SaSA), as a stable reagent is easily prepared by the reaction of saccharin with neat chlorosulfonic acid at room temperature. This compound is able to catalyze conversion of amines to their corresponding N-Boc protected amines with (Boc)2O. Alcohols were also converted to their corresponding tert-butyl ethers. All reactions took place under mild conditions giving the desired products in good to high yields.
• Shirini,Zolfigol,AbediniM.
• experimental part

  p. 603 - 607

  (2010/10/21)
• 

• Pd-catalyzed amidation of aryl(Het) halides with tert-butyl carbamate
• Pd-catalyzed cross-coupling reaction of tert-butyl carbamate with various aryl(Het) halides with Cs2CO3 as base in 1,4-dioxane as solvent was investigated, which resulted in the formation of the desired compounds in moderate to excellent yields.
• Qin, Lijin,Cui, Hongmeng,Zou, Dapeng,Li, Jingya,Wu, Yangjie,Zhu, Zhiwu,Wu, Yusheng
• experimental part

  p. 4445 - 4448

  (2010/09/12)
• 

• An efficient and chemoselective Br?nsted acidic ionic liquid-catalyzed N-Boc protection of amines
• The first report of a Br?nsted acidic ionic liquid, 1-methylimidazolium tetrafluoroborate [(HMIm)BF4], catalyzed efficient and chemoselective N-Boc protection of various amines using (Boc)2O is presented. Optically pure amino alcohols and amino acid esters were converted efficiently to their corresponding optically pure N-Boc derivatives. The reported method is mild, solvent-free and has the advantages of both homogeneous and heterogeneous catalysis with high product yields, selectivity and ease of product separation.
• Sunitha, Sadula,Kanjilal, Sanjit,Reddy, P. Srinivasa,Prasad, Rachapudi B.N.

• p. 2527 - 2532

  (2008/09/19)
•