- Synthesis, catalytic activity and redox properties of palladium(0) complexes with 15-membered triolefinic macrocyclic ligands containing one, two or three ferrocenyl groups
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A series of 15-membered triolefinic macrocycles containing ferrocenyl groups and their palladium(0) complexes have been synthesized and characterized. Their catalytic activity has been demonstrated in Suzuki-type cross-coupling and in the Heck reaction. Their redox properties have been investigated by means of cyclic voltammetry.
- Llobet, Antoni,Masllorens, Ester,Moreno-Ma?as, Marcial,Pla-Quintana, Anna,Rodríguez, Montserrat,Roglans, Anna
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- Nickel-Catalyzed C(sp3)-H Functionalization of Benzyl Nitriles: Direct Michael Addition to Terminal Vinyl Ketones
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An efficient nickel(0)-catalyzed addition of benzyl nitriles to terminal vinyl ketones via C(sp3)-H functionalization has been developed. The reaction provides a novel and efficient protocol for the synthesis of α-functionalized benzyl nitriles with a wide range of structural diversity under mild reaction conditions while obviating the use of a strong base. The work might be potentially useful toward the development of an enantioselective variant using chiral nitrogen ligands.
- Zhang, Ninghui,Zhang, Chunli,Hu, Xiaoping,Xie, Xin,Liu, Yuanhong
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supporting information
p. 6004 - 6009
(2021/07/31)
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- Synthesis method of azetidine silicon precursor compound and method for synthesizing six-membered silicon-nitrogen heterocyclic compound by using azetidine silicon precursor compound
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The invention discloses a synthesis method of an azetidine silicon precursor compound and a method for synthesizing a six-membered silicon nitrogen heterocyclic compound by using the azetidine silicon precursor compound, and belongs to the technical field
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Paragraph 0091-0095
(2021/06/26)
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- A Radical-Initiated Fragmentary Rearrangement Cascade of Ene-Ynamides to [1,2]-Annulated Indoles via Site-Selective Cyclization
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Straightforward access to [1,2]-annulated indoles, key substructures in natural products, is highly desirable yet challenging. Herein, a radical triggered fragmentary cyclization cascade reaction of ene-ynamides is presented, providing a rapid access into [1,2]-annulated indoles by an intermolecular radical addition, intramolecular cyclization, desulfonylative aryl migration, and site-selective C(sp2)-N cyclization sequence. DFT calculations support oxidation of N-centered radical species to cations prior to the C-N bond formation, followed by an unusual aza-Nazarov cyclization.
- Li, Sifan,Wang, Yu,Wu, Zibo,Shi, Weiliang,Lei, Yibo,Davies, Paul W.,Shu, Wei
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supporting information
p. 7209 - 7214
(2021/09/14)
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- Ni/AntPohs-Catalyzed Stereoselective Asymmetric Intramolecular Reductive Coupling of N-1,6-Alkynones
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An efficient nickel-catalyzed stereoselective asymmetric intramolecular reductive coupling of N-1,6-alkynones is reported. A P-chiral monophosphine ligand AntPhos was found to be a privileged catalyst for constructing versatile functionalized chiral pyrro
- Chen, Wanjun,Cheng, Yaping,Zhang, Tao,Mu, Yu,Jia, Wenqi,Liu, Guodu
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p. 5166 - 5182
(2021/05/05)
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- DirectN-glycosylation of tosyl and nosyl carbamates with trichloroacetimidate donors
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Under catalyst and additive-free conditions, a convenient and highly efficient eco-friendly method for the stereoselective synthesis ofN-glycofuranosyl and glycofuranosyl sulfonamides has been developed. The two-component reaction of glycofuranosyl trichloroacetimidates with a wide range of tosyl and nosyl carbamate acceptors having varying pKa-values including non-sugar-, and sugar-derived carbamates as well as amino acid-derived carbamates, proceeded smoothly with good yield and β-stereoselectivity. In addition, the selective deprotection ofN-carbamates andN-sulfonyl groups of theN-glycoside functioning as orthogonal protective groups was performed for further functionalization of theN-glycosides.
- Khanam, Ariza,Mandal, Pintu Kumar
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supporting information
p. 15386 - 15391
(2021/09/07)
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- Alkene Syn- And Anti-Oxyamination with Malonoyl Peroxides
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Malonoyl peroxide 6 is an effective reagent for the syn- or anti-oxyamination of alkenes. Reaction of 6 and an alkene in the presence of O-tert-butyl-N-tosylcarbamate (R3 = CO2 tBu) leads to the anti-oxyaminated product in up to 99% yield. Use of O-methyl-N-tosyl carbamate (R3 = CO2Me) as the nitrogen nucleophile followed by treatment of the product with trifluoroacetic acid leads to the syn-oxyaminated product in up to 77% yield. Mechanisms consistent with the observed selectivities are proposed.
- Curle, Jonathan M.,Perieteanu, Marina C.,Humphreys, Philip G.,Kennedy, Alan R.,Tomkinson, Nicholas C. O.
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supporting information
p. 1659 - 1664
(2020/02/13)
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- An unconventional sulfur-to-selenium-to-carbon radical transfer: Chemo-and regioselective cyclization of yne-ynamides
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An uncommon sulfur → selenium → carbon radical transfer process is employed to develop an unprecedented selenyl radical-mediated regioselective cyclization of yne-tethered-ynamides. Density functional theory studies and HRMS experiments are used to establish a reactivity scale between thiyl and selenyl radicals. The unique features of this transformation include, (1) the chemoselective reactivity of RSe over RS, (2) regioselective RSe attack on alkyne over ynamide, (3) 5-exo-dig cyclization of yne-ynamide to unusual 4-selenyl-pyrroles, and (4) the green synthetic method. The reaction of methyldiselenide with yne-ynamides to methylselenopyrroles is also described.
- Dutta, Shubham,Prabagar,Vanjari, Rajeshwer,Gandon, Vincent,Sahoo, Akhila K.
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supporting information
p. 1113 - 1118
(2020/03/11)
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- Alkyne Versus Ynamide Reactivity: Regioselective Radical Cyclization of Yne-Ynamides
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Ynamides are typically more reactive than simple alkynes and olefins. However, a serendipitous observation revealed a rare case where the reactivity of simple alkynes exceeds that of ynamides. This led to the development of a unique sulfur-radical-triggered cyclization of yne-tethered ynamides, which involves attack of the alkyne by a thiyl radical followed by cyclization with the ynamide. A wide range of novel 4-thioaryl pyrroles that could tolerate common functional moieties and N-protecting groups were expediently constructed by this strategy. The current method contrasts with the typical cyclization of yne-ynamides, which involves the attack of the alkyne moiety by the ynamide core. Control experiments and DFT calculations supported the participation of the sulfur radical in the reaction and the regioselective cyclization. The synthetic potential of the substituted pyrroles is also discussed.
- Dutta, Shubham,Mallick, Rajendra K.,Prasad, Rangu,Gandon, Vincent,Sahoo, Akhila K.
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supporting information
p. 2289 - 2294
(2019/01/25)
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- Self-promoted and stereospecific formation of N-glycosides
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A stereoselective and self-promoted glycosylation for the synthesis of various N-glycosides and glycosyl sulfonamides from trichloroacetimidates is presented. No additional catalysts or promoters are needed in what is essentially a two-component reaction. When α-glucosyl trichloroacetimidates are employed, the reaction resulted in the stereospecific formation of the corresponding β-N-glucosides in high yields at ambient conditions. On the other hand, when equatorial glucosyl donors were used, the stereospecificity decreased and resulted in a mixture of anomers. By NMR-studies, it was concluded that this decrease in stereospecificity was due to an, until now, unpresented anomerization of the trichloroacetimidate under the very mildly acidic conditions. The mechanism and kinetics of the glycosylations have been studied by NMR-experiments, which gave an insight into the activation of trichloroacetimidates, suggesting an SNi-like mechanism involving ion pairs. The scope of glycosyl donors and sulfonamides was found to be very broad including popular N-protective groups and common glycosyl donors of various reactivity. Peracetylated GlcNAc trichloroacetimidate could be used without the need for any promotors or additives and a tyrosine side chain was glycosylated as an N-glycosyl carbamate. The N-carbamates and the N-sulfonyl groups functioned as orthogonal protective groups of the N-glycoside and hence allowed further N-functionalization without risking mutarotation of the N-glycoside. The N-glycosylation was also performed on a gram scale, without a drop in stereoselectivity nor yield.
- Nielsen, Michael Martin,Ma?a, Patrycja,Baldursson, Eirikur Pórir,Pedersen, Christian Marcus
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p. 5299 - 5307
(2019/05/29)
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- Unprecedented nucleophile-promoted 1,7-S or Se shift reactions under Pummerer reaction conditions of 4-alkenyl-3-sulfinylmethylpyrroles
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A unique 1,7-S- and Se-shift reaction under Pummerer reaction conditions of 4-alkenyl-3-sulfinyl- and seleninylpyrroles was described. The usual Pummerer reaction of 4-(alkenylaminomethyl)-3-phenylsulfinylpyrroles and a successive reaction with tetrabutyl
- Go, Takashi,Morimatsu, Akane,Wasada, Hiroaki,Tanabe, Genzoh,Muraoka, Osamu,Sawada, Yoshiharu,Yoshimatsu, Mitsuhiro
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supporting information
p. 2722 - 2729
(2018/11/21)
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- Annelated Cyclobutanes by Fe-Catalyzed Cycloisomerization of Enyne Acetates
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Cationic Fe complexes of the general type [(Ph3P)2Fe(CO)(NO)]X (X=BF4, BArF4) catalyze the redox-neutral cycloisomerization of 1,6- and 1,7-enyneacetates to afford bicyclic cyclobutanes under mild conditions in good yields and diastereoselectivities.
- Kramm, Frederik,Teske, Johannes,Ullwer, Franziska,Frey, Wolfgang,Plietker, Bernd
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supporting information
p. 13335 - 13338
(2018/09/25)
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- Synthesis of Polyheterocyclic Tropones by [2 + 2 + 2 + 1] Carbonylative Cycloaddition of Triynes
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A direct synthesis of tropones (2,4,6-cycloheptatrienes) from simple preorganized triynes has been elaborated. This simple rhodium-catalyzed domino strategy allows one-pot access to fully substituted tropones in a 6-6-7-5 tetracyclic core in average to hi
- Salacz, Laura,Girard, Nicolas,Blond, Ga?lle,Suffert, Jean
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supporting information
p. 3915 - 3918
(2018/07/25)
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- Reactivity of Arynes for Arene Dearomatization
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An unprecedented aryne-mediated dearomatization reaction is described. An aryne intermediate generated from arenesulfonyl ynamide-tethered triynes and tetraynes reacts with both the π-systems of a tethered alkene and the arenesulfonyl group to generate cy
- Karmakar, Rajdip,Le, Anh,Xie, Peipei,Xia, Yuanzhi,Lee, Daesung
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supporting information
p. 4168 - 4172
(2018/07/29)
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- Diastereoselective and Enantiospecific Synthesis of 1,3-Diamines via 2-Azaallyl Anion Benzylic Ring-Opening of Aziridines
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The 1,3-diamine motif appears in numerous complex molecules, yet there are few methods for the stereoselective construction of this moiety. Herein, we demonstrate a stereocontrolled synthesis of 1,3-diamines, which bear up to three contiguous stereogenic centers, through benzylic ring-opening of aziridines with 2-azaallyl anion nucleophiles. Reactions proceed efficiently (yield up to 95%), diastereoselectively (dr up to >20:1), site selectively, and enantiospecifically to deliver products with differentiated amino groups.
- Li, Kangnan,Weber, Alexandria E.,Tseng, Luke,Malcolmson, Steven J.
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supporting information
p. 4239 - 4242
(2017/08/23)
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- Olefin-Migrative Cleavage of Cyclopropane Rings through the Nickel-Catalyzed Hydrocyanation of Allenes and Alkenes
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A nickel-catalyzed hydrocyanation triggered by hydronickelation of the carbon-carbon double bonds of allenes followed by cyclopropane cleavage is described. The observed regio- and stereochemistries in the products are strongly influenced by the initial hydronickelation step, and allenyl- and methylenecyclopropanes reacted smoothly to promote the cleavage of cyclopropane. In contrast, this cleavage was not observed with vinylidenecyclopropanes, because the initial hydronickelation does not give a suitable intermediate for cleavage of the cyclopropanes. (Figure presented.).
- Hori, Hiroto,Arai, Shigeru,Nishida, Atsushi
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supporting information
p. 1170 - 1176
(2017/04/13)
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- Preference of Ruthenium-Based Metathesis Catalysts toward Z- and E-Alkenes as a Guide for Selective Reactions to Alkene Stereoisomers
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As a guide for selective reactions toward either Z- or E-alkene in a metathesis reaction, the relative preference of metathesis Ru catalysts for each stereoisomer was determined by a method using time-dependent fluorescence quenching. We found that Ru-1 p
- Lee, Jihong,Kim, Kyung Hwan,Lee, Ok Suk,Choi, Tae-Lim,Lee, Hee-Seung,Ihee, Hyotcherl,Sohn, Jeong-Hun
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p. 7591 - 7596
(2016/09/09)
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- Total Synthesis of (+)-Mesembrine Applying Asymmetric Gold Catalysis
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The total synthesis of enantiomerically pure (+)-mesembrine is described. The central pyrrolidine moiety incorporating a quaternary, all-carbon-substituted stereocenter was constructed employing an asymmetric gold-catalyzed cycloisomerization of a 1,4-diynamide.
- Spittler, Michael,Lutsenko, Kiril,Czekelius, Constantin
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p. 6100 - 6105
(2016/07/26)
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- Simple, rapid, and clean condensation of sulfonamide and maleic anhydride derivatives: Synthesis of novel 1H- Pyrrole-2,5-diones under heterogeneous conditions
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H6P2W18O62is used as an efficient catalyst for the synthesis of novel N-substituted sulfonyl maleimides (1H-Pyrrole-2,5-diones) via the condensation of sulfonamide and maleic anhydride derivatives. The Dawson heteropolyacid was used with a catalytic amount of 2?mmol% in acetonitrile at reflux. The reuse of H6P2W18O62as heterogeneous catalyst several times without decrease in their activity, short reaction times, easy isolation of desired products with good to excellent yields shows the advantages of this novel methodology.
- Bougheloum, Chafika,Guezane Lakoud, Samia,Belghiche, Robila,Messalhi, Abdelrani
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supporting information
p. 1344 - 1350
(2016/09/28)
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- Sulfonyl Azides as Precursors in Ligand-Free Palladium-Catalyzed Synthesis of Sulfonyl Carbamates and Sulfonyl Ureas and Synthesis of Sulfonamides
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(Chemical Equation Presented). An efficient synthesis of sulfonyl carbamates and sulfonyl ureas from sulfonyl azides employing a palladium-catalyzed carbonylation protocol has been developed. Using a two-chamber system, sulfonyl azides, PdCl2, and CO gas, released ex situ from Mo(CO)6, were assembled to generate sulfonyl isocyanates in situ, and alcohols and aryl amines were exploited as nucleophiles to afford a broad range of sulfonyl carbamates and sulfonyl ureas. A protocol for the direct formation of substituted sulfonamides from sulfonyl azides and amines via nucleophilic substitution was also developed.
- Chow, Shiao Y.,Stevens, Marc Y.,Odell, Luke R.
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p. 2681 - 2691
(2016/04/26)
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- Microwave Promoted Transcarbamylation Reaction of Sulfonylcarbamates under Continuous-Flow Conditions
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Successful conditions for the transcarbamylation/transesterification reaction of sulfonylcarbamates with alcohols by microwave heating under continuous-flow conditions were developed. After optimization of the processes, two series of O-alkylsulfonylcarbamates were obtained in high yields and purities using microwave transparent borosilicate tube reactors. In order to also illustrate the usefulness of the protocol in a medicinal chemistry context, the methodology was used for the synthesis of three angiotensin II type 2 receptor ligands.
- Kumpina, Ilze,Isaksson, Rebecka,S?vmarker, Jonas,Wannberg, Johan,Larhed, Mats
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p. 440 - 445
(2016/03/04)
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- Rapid and straightforward transesterification of sulfonyl carbamates
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A fast and convenient method for the alkoxy exchange of sulfonyl carbamates by simply heating in a chosen alkyl alcohol is described. No catalysts or additives are required. Microwave heating at 100-120 °C for 20-60 min resulted in good to excellent yields (53-93%) of alkyl (arylsulfonyl)carbamates where the alkyl part originates from the alcohol solvent. The developed protocol was applied to the synthesis of an angiotensin II type 2 receptor (AT2R) ligand.
- Isaksson, Rebecka,Kumpi?a, Ilze,Larhed, Mats,Wannberg, Johan
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p. 1476 - 1478
(2016/03/12)
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- Cu-Catalyzed silylation of alkynes: A traceless 2-pyridylsulfonyl controller allows access to either regioisomer on demand
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The Cu-catalyzed silylation of terminal and internal alkynes bearing a 2-pyridyl sulfonyl group (SO2Py) at the propargylic position affords a breadth of vinyl silanes in good yields and with excellent regio- and stereocontrol under mild conditi
- García-Rubia, Alfonso,Romero-Revilla, Jose A.,Mauleón, Pablo,Gómez Arrayás, Ramón,Carretero, Juan C.
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supporting information
p. 6857 - 6865
(2015/06/16)
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- Palladium-catalyzed oxidative 6-exo-trig cyclization of 1,6-enynes: Facile synthesis of bicyclo[4.1.0]heptan-5-ones
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We here describe a new palladium-catalyzed oxidative 6-exo-trig cyclization of 1,6-enynes at room temperature using tBuONO as an oxidant for the synthesis of 3-bicyclo[4.1.0]heptan-5-ones. This cascade strategy involves the hydration, cyclization and cycl
- Liu, Bang,Song, Ren-Jie,Ouyang, Xuan-Hui,Li, Yang,Hu, Ming,Li, Jin-Heng
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supporting information
p. 12819 - 12822
(2015/08/06)
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- Tandem Gold-Catalyzed Dehydrative Cyclization/Diels-Alder Reactions: Facile Access to Indolocarbazole Alkaloids
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A gold-catalyzed synthesis of cyclic 2-oxodienes from readily prepared propargyl alcohols and the subsequent Diels-Alder reaction are reported. The dehydrative cyclization reactions proceeded smoothly, and the dienes formed in situ were demonstrated to un
- Borrero, Nicholas V.,Deratt, Lindsey G.,Ferreira Barbosa, Lais,Abboud, Khalil A.,Aponick, Aaron
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supporting information
p. 1754 - 1757
(2015/04/14)
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- Efficient, scalable and economical preparation of tris(deuterium)- and 13C-labelled N-methyl-N-nitroso-p-toluenesulfonamide (Diazald) and their conversion to labelled diazomethane
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A method for the preparation of multi-gramme quantities of N-methyl-d3-N-nitroso-p-toluenesulfonamide (Diazald-d3) and N-methyl-13C-N-nitroso-p-toluenesulfonamide (Diazald-13C) and their conversion to diazomethane-d2 and diazomethane-13C, respectively, is presented. This approach uses robust and reliable chemistry, and critically, employs readily commercially available and inexpensivemethanol as the label source. Several reactions of labelled diazomethane are also reported, including alkene cyclopropanation, phenolmethylation and α-diazoketone formation, as well as deuteriumscrambling in the preparation of diazomethane-d2 and subsequent methyl esterification of benzoic acid.
- Shields, Samuel W.J.,Manthorpe, Jeffrey M.
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p. 674 - 679
(2015/01/16)
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- Rhodium-catalyzed carbonylative [3 + 2 + 1] cycloaddition of alkyne-tethered alkylidenecyclopropanes to phenols in the presence of carbon monoxide
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A novel Rh-catalyzed carbonylative [3 + 2 + 1] cycloaddition of alkyne-tethered alkylidenecyclopropanes for the facile synthesis of bicyclic phenols in high yields has been developed. The reaction tolerated carbon and heteroatoms in the tether.
- Kim, Seyun,Chung, Young Keun
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supporting information
p. 4352 - 4355
(2015/01/09)
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- Iron(ii)-catalysed [2+2+2] cycloaddition for pyridine ring construction
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We report a new, simple and air-stable iron(ii) complex pre-catalyst for the synthesis of substituted pyridines via a [2+2+2] cycloaddition between diynes and nitrile derivatives. The Royal Society of Chemistry 2014.
- Richard, Vincent,Ipouck, Melinda,Merel, Delphine S.,Gaillard, Sylvain,Whitby, Richard J.,Witulski, Bernhard,Renaud, Jean-Luc
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supporting information
p. 593 - 595
(2014/01/06)
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- Synthesis of azepine derivatives by silver-catalyzed [5+2] cycloaddition of γ-amino ketones with alkynes
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Silver forges the ring: A new and practical silver-catalyzed [5+2] cycloaddition method has been developed for the synthesis of azepines through the formation of four new chemical bonds between a γ-amino ketone and an alkyne in one step. This method provi
- Zhou, Ming-Bo,Song, Ren-Jie,Wang, Cheng-Yong,Li, Jin-Heng
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supporting information
p. 10805 - 10808
(2013/10/22)
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- ZnO nanorods as an efficient and heterogeneous catalyst for N-Boc protection of amines and amine derivatives
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An efficient ZnO nano catalyst, which was readily prepared from Zn(CH3CO2)2, 2H2O and PVP by a chemical solution approach has successfully catalyzed N-tertbutoxy carbonylation of amines. The ZnO nanorods were successful and gave promising results for highly active and chemoselective as well as easily recyclable catalyst for the NBoc protection reaction of a wide variety of amines. The catalyst could be easily recycled for five times without noticeable decrease in catalytic activity. The ZnO nanocatalyst was characterized with XRD and SEM.
- Nouria, Azita,Akbari, Jafar,Heydaric, Akbar,Nouri, Arezu
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experimental part
p. 38 - 42
(2012/05/04)
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- Titanium(IV) chloride-mediated carbocyclization of 1,6-Enynes: Selective synthesis of 3-Azabicyclo[3.1.0]hexanes and functionalized allenes by controlling the reaction temperature
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1,6-Enynes can be transformed into 3-azabicyclo[3.1.0]hexanes and functionalized allenes in moderate to good yields along with moderate to high diastereoselectivities by controlling the reaction temperature in the presence of titanium(IV) chloride. A plausible mechanism is proposed. 1,6-Enynes can be transformed into 3-azabicyclo[3.1.0]hexanes and functionalized allenes respectively in moderate to goodyields along with moderate to high diastereoselectivities by controlling the reaction temperature in the presence of titanium(IV) chloride. A plausible mechanism is proposed.
- Zhang, Zhen,Shi, Min
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supporting information; scheme or table
p. 2610 - 2614
(2011/06/28)
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- An efficient, overall [4+1] cycloadditon of 1,3-dienes and nitrene precursors
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Intermolecular cycloadditions of conjugated dienes and nitrene precursors usually produce aziridines. A generally useful method was lacking to directly provide the [4+1] cycloadducts, 3-pyrrolines. We have realized this transformation by using an uniquely active catalyst, copper(II) 1,1,1,5,5,5-hexafluoroacetylacetonate ([Cu(hfacac)2]). The method is applicable to a wide array of dienes with good yields. When 1,4-disubsituted dienes are used as substrates, good-to-excellent cis or trans selectivity can be obtained. Interestingly, the cis or trans preference depends on the nature of the substituents, rather than diene geometry. Mechanistic studies reveal that the [4+1] cycloaddition proceeds through diene aziridination and subsequent ring expansion. Among common copper catalysts, only [Cu(hfacac)2] can efficiently catalyze both steps, which explains the unique efficiency of the catalyst.
- Wu, Qiong,Hu, Jian,Ren, Xinfeng,Zhou, Jianrong
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supporting information; experimental part
p. 11553 - 11558
(2011/11/29)
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- Enantioselective IrI-catalyzed carbocyclization of 1,6-enynes by the chiral counterion strategy
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Enantioenriched bicyclo[4.1.0]hept-2-enes were synthesized by Ir I-catalyzed carbocyclization of 1,6-enynes. No chiral ligands were used, CO and PPh3 were the only ligands bound to iridium. Instead, the stereochemical information was
- Barbazanges, Marion,Auge, Mylene,Moussa, Jamal,Amouri, Hani,Aubert, Corinne,Desmarets, Christophe,Fensterbank, Louis,Gandon, Vincent,Malacria, Max,Ollivier, Cyril
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experimental part
p. 13789 - 13794
(2012/01/06)
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- Protic ionic liquid [TMG][Ac] as an efficient, homogeneous and recyclable catalyst for Boc protection of amines
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An efficient and practical protocol for the chemoselective N-Boc protection of various structurally different aryl, aliphatic and heterocyclic amines was carried out with (Boc)2O using protic 1, 1, 3, 3-tetra-methylguanidinium acetate (10 mol%) as recyclable catalyst under solvent free condition at ambient temperature. No competitive side reactions (isocyanate, urea and N, N-di-Boc) were observed. α-Amino alcohols afforded the N-Boc-derivative without oxazolidinone formation.
- Akbari, Jafar,Heydari, Akbar,Ma'mani, Leila,Hassan Hosseini, Seyed
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experimental part
p. 544 - 547
(2010/11/05)
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- A catalytic, Bronsted base strategy for intermolecular allylic C-H amination
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A Bronsted base activation mode for oxidative, Pd(II)/sulfoxide- catalyzed, intermolecular C-H allylic amination is reported. N,N-diisopropylethylamine was found to promote amination of unactivated terminal olefins, forming the corresponding linear allylic amine products with high levels of stereo-, regio-, and chemoselectivity. The predictable and high selectivity of this C-H oxidation method enables latestage incorporation of nitrogen into advanced synthetic intermediates and natural products.
- Reed, Sean A.,Mazzotti, Anthony R.,White, M. Christina
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supporting information; scheme or table
p. 11701 - 11706
(2009/12/08)
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- An efficient and chemoselective Br?nsted acidic ionic liquid-catalyzed N-Boc protection of amines
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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.
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p. 2527 - 2532
(2008/09/19)
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- N-tert-Butoxycarbonylation of amines using H3PW12O40 as an efficient heterogeneous and recyclable catalyst
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The commercially available heteropoly acid H3PW12O40 (0.5 mol %) is a very efficient and environmentally benign catalyst for N-tert-butoxycarbonylation of amines (primary, secondary) with di-tert-butyl dicarbonate at room temperature in short reaction times (10 min). No competitive side products such as isocyanates, ureas, N,N-di-tert-butoxycarbonyls, O-Boc and oxazolidinones were observed. Chiral α-amino alcohols and esters afforded the corresponding N-Boc derivatives chemoselectively in excellent yields.
- Heydari, Akbar,Shiroodi, Roohollah Kazem,Hamadi, Hossein,Esfandyari, Maryam,Pourayoubi, Mehrdad
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p. 5865 - 5868
(2008/02/09)
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- A highly chemoselective Boc protection of amines using sulfonic-acid-functionalized silica as an efficient heterogeneous recyclable catalyst
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A facile and versatile method for the chemoselective Boc protection of amines has been developed by a treatment with (Boc)2O in the presence of sulfonic-acid-functionalized silica as a catalyst. The method is general for the preparation of N-Boc derivatives of aliphatic (acyclic and cyclic), aromatic, and heteroaromatic amines; primary and secondary amines; aminols, amino-esters; and sulfonamides. The catalyst works under heterogeneous conditions and can be recycled.
- Das, Biswanath,Venkateswarlu, Katta,Krishnaiah, Maddeboina,Holla, Harish
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p. 7551 - 7556
(2008/02/08)
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- Molecular iodine-catalyzed facile procedure for N-Boc protection of amines
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An efficient and practical protocol for the protection of various structurally and electronically divergent aryl and aliphatic amines using (Boc)2O in the presence of a catalytic amount of molecular iodine (10 mol%) under solvent-free conditions at ambient temperature is presented.
- Varala, Ravi,Nuvula, Sreelatha,Adapa, Srinivas R.
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p. 8283 - 8286
(2007/10/03)
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- Lithium perchlorate-catalyzed Boc protection of amines and amine derivatives
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A new mild and chemoselective method for mono-N-protection of amines and amine derivatives as tert-butoxycarbonyl derivatives is reported. The reaction proceeds with lithium perchlorate (20 mol %) and pyrocarbonates, and shows general applicability. The catalytic action of LiClO4 is specific for the activation of Boc2O, thus acid-sensitive functionalities of the starting materials remain unchanged in the protection process. This procedure works well for sterically hindered primary amine as well as electron-deficient primary arylamines, primary and secondary amino alcohols, α-amino acid esters, hydroxylamines, hydrazines and sulfonamides.
- Heydari, Akbar,Hosseini, Seyed Esmaeil
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p. 1929 - 1932
(2007/10/03)
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- Excitatory amino acid receptor antagonists
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The present invention provides compounds of Formula I or Formula II, or the pharmaceutically acceptable salts or prodrugs thereof, pharmaceutical compositions comprising compounds or Formula I or Formula II, and methods for treating neurological disorders and neurodegenerative diseases, particularly migraine.
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- A reversible safety-catch method for the hydrogenolysis of N-benzyl moieties
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The benzyl groups of β-hydroxy-N-benzyl sulfonamides are labile toward hydrogenolysis-unlike N-benzyl sulfonamides lacking the β-hydroxy moiety. We find that N-acyl-N-benzyl sulfonamides undergo hydrogenolysis under very mild conditions. Based upon these observations, we developed a reversible safety-catch method using tert-butoxycarbonyl moieties to activate N-benzyl sulfonamides toward hydrogenolysis. We also explored the utility of the safety-catch activation method for other nitrogen-based functionality such as N-benzyl carboxamides, imides, and related functionality.
- Johnson II, David C.,Widlanski, Theodore S.
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p. 8483 - 8487
(2007/10/03)
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- Scavenge-ROMP-filter: a facile strategy for soluble scavenging via norbornenyl tagging of electrophilic Reagents.
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[reaction: see text] A new "chemical tagging" method for homogeneous electrophilic scavenging is described. The method utilizes 5-norbornene-2-methanol to scavenge/tag a variety of electrophiles that are present in excess. Once tagging is complete, the crude reaction mixture is subjected to a rapid ROM polymerization event utilizing the second generation Grubbs catalyst. This process yields a polymer that can be precipitated with methanol or ether/hexane, leaving products in excellent yield and purity.
- Moore, Joel D,Harned, Andrew M,Henle, Julia,Flynn, Daniel L,Hanson, Paul R
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p. 1847 - 1849
(2007/10/03)
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- Preparation of nitrogen-containing 15-membered triolefinic macrocycles: (E,E,E)-1,6,11-tris(arylsulfonyl)-1,6,11-triazacyclopentadeca-3,8,13-trienes
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Three routes to (E,E,E)-1,6,11-tris(arylsulfonyl)-1,6,11-triazacyclopentadeca-3,8,13-trienes are described. Optimization of the preparation of key intermediates has opened the way to efficient synthesis of a broad variety of 15-membered, nitrogen-containing triolefinic macrocycles.
- Cerezo, Silvia,Cortès, Jordi,Galvan, David,Lago, Elena,Marchi, Caroline,Molins, Elies,Moreno-Ma?as, Marcial,Pleixats, Roser,Torrejón, Javier,Vallribera, Adelina
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p. 329 - 337
(2007/10/03)
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- New route to 4-aminocyclopent-2-en-1-ols: Synthesis and enantioselective rearrangement of 4-amino-substituted cyclopentene oxides
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A new route for the asymmetric synthesis of 4-aminocyclopent-2-en-1-ols (90% ee) for carbocyclic nucleoside analogue synthesis is described. The approach involves the stereoselective preparation of cis 4-amino-substituted cyclopentene oxides and subsequent chiral base-mediated rearrangement to the corresponding allylic alcohols. Full details on the synthesis and stereoselectivity of epoxidation of 4-amino-substituted cyclopentenes are presented. (C) 2000 Elsevier Science Ltd.
- Barrett, Stephen,O'Brien, Peter,Steffens, H.Christian,Towers, Timothy D,Voith, Matthias
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p. 9633 - 9640
(2007/10/03)
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- Facile Preparation of N-(sulfonyl)carbamates
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N-(Sulfonyl)carbamates, useful N-nucleophiles in the Mitsunobu reaction, can be prepared readily by reaction of sulfonamides with chloroformates (or dicarbonates) catalyzed by 4-(dimethylamino)pyridine.
- Neustadt, Bernard R.
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p. 379 - 380
(2007/10/02)
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- Total synthesis of a potent thromboxane A2 antagonist
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The synthesis of the powerful thromboxane A2 antagonist 3 (EC50 3 nM) is reported.
- Corey,Su, Wei-Guo
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p. 3833 - 3836
(2007/10/02)
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- MITSUNOBU REACTIONS OF N-ALKYL AND N-ACYL SULFONAMIDES - AN EFFICIENT ROUTE TO PROTECTED AMINES
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N-Methyl p-toluenesulfonamide and N-BOC p-toluenesulfonamide can be directly coupled with primary or secundary alcohols under Mitsunobu conditions to afford various sulfonamide-protected amines.
- Henry, James R.,Marcin, Lawrence R.,McIntosh, Matthias C.,Scola, Paul M.,Harris, G. Davis,Weinreb, Steven M.
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p. 5709 - 5712
(2007/10/02)
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