- A tandem process for the synthesis of β-aminoboronic acids from aziridines with haloamine intermediates
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An unprecedented synthetic strategy is devised to generate β-aminoboronic acids from aziridines via a sequential process involving 1,2-iodoamine formation and radical borylation under light irradiation. A variety of aziridines including multiply substituted aziridines have been successfully employed as synthetic precursors, expanding their synthetic utility compared to previous methods. Mechanistic studies suggest that the boron source plays a unique role in the borylation step, and in the formation of haloamine intermediates.
- Park, Subin,Koo, Jangwoo,Kim, Weonjeong,Lee, Hong Geun
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p. 3767 - 3770
(2022/04/07)
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- Enantio- and Regioselective Palladium(II)-Catalyzed Dioxygenation of (Aza-)Alkenols
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An oxidative Pd-catalyzed intra-intermolecular dioxygenation of (aza-)alkenols has been reported, with total regioselectivity. To study the stereoselectivity, different chiral ligands as well as different hypervalent-iodine compounds have been compared. I
- Beccalli, Egle Maria,Giofrè, Sabrina,Lo Presti, Leonardo,Molteni, Letizia,Nava, Donatella
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supporting information
p. 21723 - 21727
(2021/09/08)
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- Pd(ii)-Catalyzed aerobic 1,2-difunctionalization of conjugated dienes: Efficient synthesis of morpholines and 2-morpholones
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A novel and efficient methodology concerning the Pd(ii)-catalyzed intermolecular difunctionalization of conjugated dienes is reported to synthesize a series of functionalized morpholines and 2-morpholones. Widely distributed and easily obtained β-amino alcohols and α-amino acids, as starting nitrogen and oxygen sources, are successfully applied in the difunctionalization of conjugated dienes respectively. The majority of the desired products were obtained in moderate to excellent yields. Oxygen was successfully employed as a terminal oxidant. Further transformation of the generated products allowed for the expansion of structural diversity.
- Wen, Ke,Wu, Zhengxing,Chen, Buyun,Chen, Jianzhong,Zhang, Wanbin
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supporting information
p. 5618 - 5625
(2018/08/17)
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- A One-Pot Reaction toward the Diastereoselective Synthesis of Substituted Morpholines
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The diastereoselective synthesis of various substituted morpholines has been achieved from vinyloxiranes and amino-alcohols under sequential Pd(0)-catalyzed Tsuji-Trost/Fe(III)-catalyzed heterocyclization. Using the same strategy, 2,6-, 2,5-, and 2,3-disubstituted as well as 2,5,6- and 2,3,5-trisubstituted morpholines were obtained in good to excellent yields and diastereoselectivities.
- Aubineau, Thomas,Cossy, Janine
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supporting information
p. 7419 - 7423
(2018/12/11)
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- Cis -1,2-Aminohydroxylation of Alkenes Involving a Catalytic Cycle of Osmium(III) and Osmium(V) Centers: OsV(O)(NHTs) Active Oxidant with a Macrocyclic Tetradentate Ligand
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Catalytic activity of [OsIII(OH)(H2O)(L-N4Me2)](PF6)2 (1: L-N4Me2 = N,N′-dimethyl-2,11-diaza-[3,3](2,6)pyridinophane) in 1,2-cis-aminohydroxylation of alkenes with sodium N-chloro-4-methylbenzenesulfonamide (chloramine-T) is explored. Simple alkenes as well as those containing several types of substituents are converted to the corresponding 1,2-aminoalcohols in modest to high yields. The aminoalcohol products have exclusively cis conformation with respect to the introduced -OH and -NHTs groups. The spectroscopic measurements including cold mass spectroscopic study of the reaction product of complex 1 and chloromine-T as well as density functional theory (DFT) calculations indicate that an oxido-aminato-osmium(V) species [OsV(O)(NHTs)(L-N4Me2)](PF6)2 (2) is an active oxidant for the aminohydroxylation. The DFT calculations further indicate that the reaction involves a [3 + 2] cycloaddition between 2 and alkene, and the regioselectivity in the aminohydroxylation of unsymmetrical alkenes is determined by the orientation that bears less steric hindrance from the tosylamino group, which leads to the energetically more preferred product isomer.
- Sugimoto, Hideki,Mikami, Akine,Kai, Kenichiro,Sajith,Shiota, Yoshihito,Yoshizawa, Kazunari,Asano, Kaori,Suzuki, Takeyuki,Itoh, Shinobu
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p. 7073 - 7082
(2015/08/03)
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- Stereoselective synthesis of morpholines via copper-promoted oxyamination of alkenes
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A new copper(II) 2-ethylhexanoate-promoted addition of an alcohol and an amine across an alkene (oxyamination) is reported. The alcohol addition is intramolecular, while coupling with the amine occurs intermolecularly. Several 2-aminomethyl morpholines we
- Sequeira, Fatima C.,Chemler, Sherry R.
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supporting information
p. 4482 - 4485
(2012/10/29)
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- Efficient and regioselective ring-opening of arylaziridines with alcohols, thiols, amines and N-heteroaromatic compounds using sulphated zirconia
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Sulphated zirconia is an efficient catalyst for the regioselective ring-opening of aryl-substituted aziridines. This heterogeneous catalyst can be used several times without loss of activity and is compatible with a variety of acid sensitive and slightly basic nucleophiles.
- Llaveria, Josep,Espinoza, Araceli,Negrón, Guillermo,Isabel Matheu,Castillón, Sergio
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supporting information; experimental part
p. 2525 - 2529
(2012/06/18)
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- Synthesis of enantiopure 1,4-dioxanes, morpholines, and piperazines from the reaction of chiral 1,2-diols, amino alcohols, and diamines with vinyl selenones
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The reactions of readily available vinyl selenones with enantiopure 1,2-diols, N-protected-1,2-aminoalcohols, and diamines gave substituted enantiopure 1,4-dioxanes, morpholines, and piperazines, respectively, in good to excellent yields. The same procedu
- Bagnoli, Luana,Scarponi, Catalina,Rossi, Maria Giovanna,Testaferri, Lorenzo,Tiecco, Marcello
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supporting information; experimental part
p. 993 - 999
(2011/03/20)
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- Gold-catalyzed direct activation of allylic alcohols in the stereoselective synthesis of functionalized 2-vinyl-morpholines
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Alcohol versus alcohol: A highly stereocontrolled synthesis of substituted morpholines is realized by means of gold-catalyzed dehydrative allylic cyclization of diols (see scheme for one example; segphos = 5,5′-bis[di(3, 5-di-tert-butyl-4-methyoxyphenyl)phosphine]-4,4′-bi-1,3-benzodioxole). The present methodology represents one of the few examples of enantioselective gold-catalyzed transformations involving unactivated alkenes. Copyright
- Bandini, Marco,Monari, Magda,Romaniello, Alessandro,Tragni, Michele
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supporting information; body text
p. 14272 - 14277
(2011/03/19)
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- Catalyst-free process for the synthesis of 5-aryl-2-oxazolidinones via cycloaddition reaction of aziridines and carbon dioxide
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A simple approach for facile synthesis of 5-aryl-2-oxazolidinones in excellent regioselectivity from aziridines under compressed CO2 conditions was developed in the absence of any catalyst and organic solvent. The reaction outcome was found to be tuned by subtly adjusting CO2 pressure. The adduct formed in situ of aziridine and CO2 is assumed to act as a catalyst in this reaction, which was also studied by means of in situ FT-IR technique.
- Dou, Xiao-Yong,He, Liang-Nian,Yang, Zhen-Zhen,Wang, Jing-Lun
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supporting information; experimental part
p. 2159 - 2163
(2010/10/21)
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- Enantioselective syntheses of morpholines and their homologues via S N2-type ring opening of aziridines and azetidines with haloalcohols
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(Chemical Equation Presented) A highly regio- and stereoselective strategy for the syntheses in high yield and enantioselectivity of a variety of substituted nonracemic morpholines and their homologues is described. The reaction proceeds via an SN2-type ring opening of activated aziridines and azetidines by suitable halogenated alcohols in the presence of Lewis acid followed by base-mediated intramolecular ring closure of the resulting haloalkoxy amine.
- Ghorai, Manas K.,Shukla, Dipti,Das, Kalpataru
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supporting information; experimental part
p. 7013 - 7022
(2009/12/22)
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- Asymmetric Strecker reaction of N-benzhydrylimines utilising new tropos biphenyldiol-based ligands
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The synthesis of a library of N-arenesulfonyl-1,3-oxazolidinyl-substituted biphenyldiols is presented. A set of two central intermediates together with easily accessible N-arenesulfonylamino alcohols furnish a broad variety of 1,3-oxazolidines. These are applied as chiral tropos ligands in a titanium-mediated Strecker-type reaction of N-benzhydrylimines. A correlation between the ee values in the product and the diastereomeric ratio concerning the chiral axis of the ligand is made. Those substituents in the ligand which proved to lead to a higher preference for one diastereomeric conformer of the chiral axis in related compounds now provide the most selective ligands. Two privileged ligands are identified that afford superior results in 8 of 13 screenings. Wiley-VCH Verlag GmbH & Co. KGaA, 2008.
- Wuennemann, Stefan,Froehlich, Roland,Hoppe, Dieter
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p. 684 - 692
(2008/09/17)
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- Bioinspired polyene cyclization promoted by intermolecular chiral acetal-SnCl4 or chiral N-acetal-TiCl4: Investigation of the mechanism and identification of the key intermediates
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New strategies using chiral acetal or chiral mixed-acetal in the presence of Lewis acids (SnCl4 or TiCl4) to promote polyene cyclization reaction are described. Acetal-promoted and mixed-acetal-promoted polyene cyclization products a
- Zhao, Yu-Jun,Loh, Teck-Peng
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supporting information; experimental part
p. 10024 - 10029
(2009/02/04)
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- Tin-free radical addition of acyloxymethyl to imines
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(Chemical Equation Presented) Acyloxymethyl radicals were generated from the corresponding iodomethyl esters and successfully underwent addition to the C=N bond of N-Ts, N-PMP, and N-Dpp imines by the action of dimethylzinc or triethylborane. Ethyl acetate, toluene, and benzene as well as dichloromethane were suitable solvents. The utility of acyloxymethyl radicals as a hydroxymethyl anion equivalent was highlighted by the facile hydrolysis of the acyloxy moiety of the adducts to give the corresponding amino alcohol derivatives in good to high yield.
- Yamada, Ken-Ichi,Nakano, Mayu,Maekawa, Masaru,Akindele, Tito,Tomioka, Kiyoshi
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supporting information; experimental part
p. 3805 - 3808
(2009/07/01)
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- A convenient synthetic route to enantiopure N-tosylazetidines from α-amino acids
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A general and convenient synthetic route to various chiral 2-substituted- and 2,4-disubstituted-N-tosylazetidines (ee >99%) is described in good overall yields starting from chiral α-amino acids using very simple chemistry.
- Ghorai, Manas K.,Das, Kalpataru,Kumar, Amit
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p. 2471 - 2475
(2007/10/03)
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- Asymmetric radical addition of ethers to enantiopure N-p-toluenesulfinyl aldimines, mediated by dimethylzinc-air
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(Diagram presented) Asymmetric radical addition of ethers to enantiopure aromatic N-p-toluenesulfinyl aldimines has been achieved. The requisite radicals were generated by dimethylzinc-air. Lewis acid activation of the N-p-toluenesulfinyl aldimines follow
- Akindele, Tito,Yamamoto, Yasutomo,Maekawa, Masaru,Umeki, Hiroyuki,Yamada, Ken-Ichi,Tomioka, Kiyoshi
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p. 5729 - 5732
(2007/10/03)
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- Osmium-catalyzed olefin dihydroxylation and aminohydroxylation in the second catalytic cycle
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Two catalytic cycles operate in the osmium-catalyzed olefin dihydroxylation and aminohydroxylation. Slow hydrolysis of the Os(VI) monoglycolate (or monoazaglycolate in aminohydroxylation) intermediate often results in the addition of another molecule of o
- Wu, Peng,Hilgraf, Robert,Fokin, Valery V.
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p. 1079 - 1085
(2007/10/03)
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- Introduction of Functionalized C1, C2, and C3 Units to Imines through the Dimethylzinc-Air-Initiated Radical Addition
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Introduction of functionalized C1, C2, and C3 units to imines was achieved by using the dimethylzinc-air-initiated α-alkoxyalkyl radical addition as a key reaction. The addition to a C= N double bond chemoselectively occurred in the presence of a C=O doub
- Yamada, Ken-Ichi,Yamamoto, Yasutomo,Maekawa, Masaru,Tomioka, Kiyoshi
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p. 1531 - 1534
(2007/10/03)
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- Tetrabutylammonium bisulfate: A new effective catalyst for the hydrolysis of aziridines or epoxides
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Bu4NHSO4 (TBAHS) is an effective catalyst for the hydrolysis of aziridines and epoxides under mild and non-metal conditions to give the corresponding β-amino alcohols and 1,2-diols in high yields. The catalyst can be recycled.
- Fan, Ren-Hua,Hou, Xue-Long
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p. 1565 - 1567
(2007/10/03)
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- Synthesis of chiral oxazolidin-2-ones by 1,2-amino alcohols, carbon dioxide and electrogenerated acetonitrile anion
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An improved electrochemical synthesis of chiral oxazolidin-2-ones from chiral 1,2-amino alcohols is obtained by direct electrolysis of solutions of MeCN-TEAP containing the amino alcohol, with subsequent CO2 bubbling and addition of TsCl. This
- Feroci, Marta,Gennaro, Armando,Inesi, Achille,Orsini, Monica,Palombi, Laura
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p. 5863 - 5865
(2007/10/03)
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- Deprotection of sulfonyl aziridines
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The deprotection of the chiral N-sulfonyl aziridines 1-3 has been studied under different desulfonylation conditions. Two methods for the efficient aleprotection of 2-benzyl-, 2-phenyl-, and 2-carboxyl-N- sulfonylaziridines were found. The desulfonylation with lithium and a catalytic amount of di-tert-butyl biphenyl in THF at -78 °C led to the corresponding NH aziridines with yields up to 85%. Alternatively, the desulfonylation could be carried out with magnesium in methanol under ultrasonic conditions. The latter proved to be a very mild method and afforded the desulfonylated aziridines with yields up to 75%, even when the 2-phenyl substituted aziridine 2 was the studied substrate. Furthermore, in all the cases studied, no racemization was observed in the chiral center of the aziridines.
- Alonso, Diego A.,Andersson, Pher G.
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p. 9455 - 9461
(2007/10/03)
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- Cleavage of sulfonamides with phenyldimethylsilyllithium
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The toluene-p-sulfonamides of secondary amines and indoles are cleaved by treatment with phenyldimethylsilyllithium to give the secondary amines. Aziridine toluene-p-sulfonamides, however, are opened by attack of the silyllithium reagent on carbon to give β-silylethyl sulfonamides. The aziridine toluene-p-sulfonamide 22 derived from norbornene is different in giving the 2-[dimethyl(phenyl)silyl]-4-methylbenzenesulfonamide 23 of exo-norbornylamine. The aziridine toluene-p-sulfonamides 26, 28 and 30, derived from methyl cinnamate, methyl acrylate and cinnamyl acetate, are also anomalous, giving 3-[N-(p-tolylsulfonyl)amino]-3-phenylpropionic acid 27, {3-[N-(p-tolylsulfonyl)amino]propionyl}-dimethyl(phenyl)silane 29 and trans-cinnamyl alcohol 31, respectively, each derived by opening of the aziridine ring followed by loss of the silyl group.
- Fleming, Ian,Frackenpohl, Jens,Ila, Hiriyakkanavar
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p. 1229 - 1235
(2007/10/03)
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- Enantioselective fluorination of organic molecules. I. synthetic studies of the agents for electrophilic, enantioselective fluorination of carbanions
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In order to develop novel methods for electrophilic and enantioselective fluorination of active methine compounds, preliminary experiments were carried out. The N-tosyl derivative 5 obtained from D-phenylglycine was fluorinated with FC1O3 or di
- Takeuchi, Yoshio,Satoh, Akira,Suzuki, Takanori,Kameda, Ayako,Dohrin, Masahiro,Satoh, Toshihiro,Koizumi, Toru,Kirk, Kenneth L.
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p. 1085 - 1088
(2007/10/03)
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- Diastereoselective synthesis of enantiomerically pure 3-organosulfonyl-2-(2-oxocycloalkyl)-1,3-oxazolidines from 2-formylcycloalkanones and β-aminoalkanols
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The title compounds (3-arylsulfonyl- or 3-mesyl-2-(2-oxocycloalkyl)-1,3-oxazolidines) belonging to two different diastereomeric series, are prepared selectively by variation of the condensation conditions. By this, the chiral information of the 2-amino-1-
- Hoppe,Hoffmann,Gartner,Krettek,Hoppe
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p. 1157 - 1162
(2007/10/02)
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