- Sulfated tungstate: A highly efficient, recyclable and ecofriendly catalyst for chemoselective N-tert butyloxycarbonylation of amines under the solvent-free conditions
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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.
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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
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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
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supporting information
p. 1656 - 1668
(2021/04/05)
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- Ultrasound promoted environmentally benign, highly efficient, and chemoselective N-tert-butyloxycarbonylation of amines by reusable sulfated polyborate
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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.
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supporting information
p. 3768 - 3780
(2021/10/26)
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- Copper-Catalyzed C-H Fluorination/Functionalization Sequence Enabling Benzylic C-H Cross Coupling with Diverse Nucleophiles
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Site-selective transformation of benzylic C-H bonds into diverse functional groups is achieved via Cu-catalyzed C-H fluorination with N-fluorobenzenesulfonimide (NFSI), followed by substitution of the resulting fluoride with various nucleophiles. The benzyl fluorides generated in these reactions are reactive electrophiles in the presence of hydrogen-bond donors or Lewis acids, allowing them to be used without isolation in C-O, C-N, and C-C coupling reactions.
- Buss, Joshua A.,Golden, Dung L.,Stahl, Shannon S.,Vasilopoulos, Aristidis
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- One-pot synthesis of primary amines from carboxylic acids through rearrangement of in situ generated hydroxamic acid derivatives
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A one-pot synthesis of primary amines from carboxylic acids through a Lossen rearrangement of hydroxamic acid derivatives, which were in situ generated by the reaction of carboxylic acids with O-trimethylsilylhydroxylamine (NH2OTMS) and carbonyl diimidazole (CDI, 1.5 equiv) in dimethyl sulfoxide at room temperature, has been achieved. This one-pot method could be applied to various carboxylic acids such as aromatic, heteroaromatic, aliphatic, and optically active substrates.
- Hoshino, Yujiro,Ohtsuka, Naoya,Okada, Takuya,Honda, Kiyoshi
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supporting information
p. 5304 - 5307
(2016/11/16)
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- Copper(II)-acid catalyzed cyclopropanation of 1,3-dienamides by electrophilic activation of α-aryl diazoesters
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Copper(II)-acid catalyzed cyclopropanation of electron-rich alkenes, such as 1,3-dienamides, with α-aryl diazoesters are described. The reaction could be performed without rare metal catalysts, excess substrate, or the need for the slow addition of the diazoesters.
- Tayama, Eiji,Horikawa, Kouki,Iwamoto, Hajime,Hasegawa, Eietsu
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supporting information
p. 3041 - 3044
(2014/05/20)
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- Mechanistic investigations and substrate scope evaluation of ruthenium-catalyzed direct sp3 arylation of benzylic positions directed by 3-substituted pyridines
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A highly efficient direct arylation process of benzylic amines with arylboronates was developed that employs Ru catalysis. The arylation takes place with greatest efficiency at the benzylic sp3 carbon. If the distance to the activating aryl ring is increased, arylation is still possible but the yield drops significantly. Efficiency of the CH activation was found to be significantly increased by use of 3-substituted pyridines as directing groups, which can be removed after the transformation in high yield. Calculation of the energy profile of different rotamers of the substrate revealed that presence of a substituent in the 3-position favors a conformation with the CH2 group adopting a position in closer proximity to the directing group and facilitating C-H insertion. This operationally simple reaction can be carried out in argon atmosphere as well as in air and under neutral reaction conditions, displaying a remarkable functional group tolerance. Mechanistic studies were carried out and critically compared to mechanistic reports of related transformations.
- Dastbaravardeh, Navid,Kirchner, Karl,Schnuerch, Michael,Mihovilovic, Marko D.
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p. 658 - 672
(2013/02/26)
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- Ruthenium(0)-catalyzed sp3 C-H bond arylation of benzylic amines using arylboronates
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A Ru-catalyzed direct arylation of benzylic sp3 carbons of acyclic amines with arylboronates is reported. This highly regioselective and efficient transformation can be performed with various combinations of N-(2-pyridyl) substituted benzylamines and arylboronates. Substitution of the pyridine directing group in the 3-position proved to be crucial in order to achieve high arylation yields. Furthermore, the pyridine directing group can be removed in high yields via a two-step protocol.
- Dastbaravardeh, Navid,Schnuerch, Michael,Mihovilovic, Marko D.
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p. 1930 - 1933
(2012/05/31)
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- Rhodium-catalyzed arylation of α-amido sulfones with arylboronic acids in a water-toluene biphasic system
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An efficient method for the synthesis of N-protected diaryl-methyl-amines was developed through a rhodium-catalyzed arylation of α-amido sulfones with arylboronic acids in a water-toluene biphasic system. The use of a base combined with a surfactant playe
- Dou, Xiao-Yong,Shuai, Qi,He, Liang-Nian,Li, Chao-Jun
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experimental part
p. 284 - 287
(2011/06/20)
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- Atroposelective formation of dibenz[c,e]azepines via intramolecular direct arylation with centre-axis chirality transfer
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5-Substituted 6,7-dihydrodibenz[c,e]azepines, a class of secondary amine incorporating a centre-axis chirality relay, are accessible from 1-substituted N-(2-bromobenzyl)-1-phenylmethanamines via N-acylation and ring-closing intramolecular direct arylation. The ring closure proceeds with high atropodiastereoselectivity due to strain effects that are induced by trigonalisation of the nitrogen atom, as predicted using molecular mechanics calculations.
- Cheetham, Caroline A.,Massey, Richard S.,Pira, Silvain L.,Pritchard, Robin G.,Wallace, Timothy W.
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experimental part
p. 1831 - 1838
(2011/04/26)
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- Chemoselective reduction of azides catalyzed by molybdenum xanthate by using phenylsilane as the hydride source
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A chemoselective, neutral, and efficient strategy for the reduction of azides to corresponding amines catalyzed by dioxobis(N,N,-diethyldithiocarbamato) molybdenum complex (1, MoO2[S2CNEt2]2) in the presence of phenylsilane is discovered. This chemoselective reduction strategy tolerates a variety of reducible functional groups.
- Maddani, Mahagundappa R.,Moorthy, Saravana K.,Prabhu, Kandikere R.
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supporting information; experimental part
p. 329 - 333
(2010/03/01)
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- Efficient, solventless N-Boc protection of amines carried out at room temperature using sulfamic acid as recyclable catalyst
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A simple, rapid, and efficient protocol for the chemoselective N-Boc protection of amines using sulfamic acid as catalyst is described. N-Boc protection of various structurally diverse aliphatic, aromatic, alicyclic, and heterocyclic amines (1°, 2°, 3°) was carried out with (Boc)2O using sulfamic acid as catalyst (5 mol %) at room temperature under solventless conditions. The advantages of this method are simplicity, shorter reaction times (1-15 min), a cost-effective catalyst, and excellent isolated yields (90-100%); it is also environmentally benign. Moreover, the combined use of ultrasound and sulfamic acid achieves a synergic effect that is especially marked in the N-Boc protection of deactivated (sterically hindered and electron-deficient) amines. The catalyst possesses distinct advantages: ease of handling, cleaner reactions, high activity, and excellent chemoselectivity.
- Upadhyaya, Dharita J.,Barge, Alessandro,Stefania, Rachele,Cravotto, Giancarlo
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p. 8318 - 8322
(2008/04/13)
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- Rhodium-catalyzed addition of arylstannanes to carbon-heteroatom double bond
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The addition of arylstannanes to the carbon-heteroatom double bond in the presence of a catalytic amount of a cationic rhodium complex ([Rh(cod)(MeCN)2]BF4) was examined. The reactions of aldehydes, α-dicarbonyl compounds, and N-substituted aldimines with the arylstannanes gave corresponding alcohols, α-hydroxy carbonyl compounds, and amines, respectively. An arylrhodium complex generated by the transmetalation with the arylstannane was probably the active catalytic species.
- Oi, Shuichi,Moro, Mitsutoshi,Fukuhara, Hiroe,Kawanishi, Takanori,Inoue, Yoshio
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p. 4351 - 4361
(2007/10/03)
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- One-pot conversion of oximes to N-(tert-butoxycarbonyl) amines with polymethylhydrosiloxane, Pd-C and di-tert-butyl dicarbonate
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N-(tert-butoxycarbonyl) amines are directly obtained from oximes of aldehydes and ketones in one-pot when treated with polymethylhydrosiloxane (PMHS) and di-tert-butyl dicarbonate in the presence of catalytic amount of 10% Pd-C for the first time.
- Chandrasekhar,Reddy,Chandraiah
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p. 1351 - 1353
(2007/10/03)
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- Rhodium-catalyzed arylation and alkenylation of imines with organostannanes
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A rhodium complex catalyzed the addition of aryl- and alkenyl-stannanes to activated aldimines under mild and neutral conditions, affording the corresponding amines in good yields.
- Oi, Shuichi,Moro, Mitsutoshi,Fukuhara, Hiroe,Kawanishi, Takanori,Inoue, Yoshio
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p. 9259 - 9262
(2007/10/03)
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