- Syntheses, structures and catalytic activities of low-coordinated rare-earth metal complexes containing 2,2′-pyridylpyrrolides
-
Reactions of the ligand precursors 2-(2′-pyridyl)-3,5-Me2-pyrrole (L1H) and 2-(2-pyridyl)-3,4,5-Me3-pyrrole (L2H) with [(Me3Si)2N]3RE(μ-Cl)Li(THF)3 in toluene afforded a series of low-coordinated rare-earth metal bis-amido complexes L1RE[N(SiMe3)2]2 [RE = Y (1a), Dy (1b), Er (1c), Yb (1d)] and L2RE[N(SiMe3)2]2 [RE = Y (2a), Dy (2b), Er (2c), Yb (2d)]. With the ionic radius of rare-earth metal increasing, the reaction of L1H and [(Me3Si)2N]3RE(μ-Cl)Li(THF)3 gave dinuclear complexes (L1)2RE(μ-Cl)(μ-η5:η1:η1-L1)RE(L1)[N(SiMe3)2]2 [RE = Sm (1e), Pr (1f)]; however, the reaction of L2H and [(Me3Si)2N]3Sm(μ-Cl)Li(THF)3 afforded (L2)2Sm[N(SiMe3)2]2 (2e). Results indicated that the ionic radius of rare-earth metal and subtle change in the ligands have substantial effects on the structure and bonding mode of complexes. The complexes showed a high catalytic activity for the ring-opening reaction of cyclohexene oxide with amines to afford various β-aminoalcohols under mild solvent-free conditions.
- Du, Jun,Zhou, Shuangliu,Zhang, Xiuli,Zhang, Lijun,Cui, Peng,Huang, Zeming,Wei, Yun,Zhu, Xiancui,Wang, Shaowu
-
-
- Asymmetric amination of meso-epoxide with vegetable powder as a low-toxicity catalyst
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This paper describes the scope and limitation of substrates subjected to asymmetric amination with epoxides catalyzed by a soluble soybean polysaccharide (Soyafibe S-DN), which we recently discovered from the reaction of 1,2-epoxycyclohexane with cyclopropylamine. Various meso-epoxides reacted with various amines afforded the corresponding products with good enantiomeric selectivity. Since it was found that pectin was found to have a catalytic ability after screening commercially available polysaccharides, we studied 33 different vegetable powders having pectic substances, and we found that many vegetable powders showed catalytic ability. These results should guide in using vegetable components as low-toxic catalysts for the production of pharmaceuticals.
- Asano, Tatsuhiro,Kurata, Hiroyuki,Takeuchi, Yuki,Tsuzaki, Kazuya,Wada, Koichi
-
-
- Microwave-Assisted CuCl-Catalyzed Three-Component Reactions of Alkynes, Aldehydes, and Amino Alcohols
-
A microwave (MW)-assisted three-component coupling of amino alcohols, aldehydes, and alkynes is developed under catalysis by CuCl. Compared with thermal conditions, MW irradiation greatly increases the reaction efficiency. The reactions of various primary N -alkyl/arylamino alcohols, aliphatic/aromatic aldehydes, and alkynes are systematically investigated, affording the desired products in moderate to good yields. Notably, acetylene is also an effective reactant under the current MW-assisted conditions.
- Chen, Ning,Li, Xiang,Xu, Jiaxi
-
supporting information
p. 3336 - 3344
(2019/08/28)
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- Broadening the chemical scope of laccases: Selective deprotection of N-benzyl groups
-
Laccase from Trametes versicolor together with TEMPO has been found to be a very efficient system to deprotect N-benzylated primary amines, differing from previously described methods since it uses oxygen as a mild oxidant in aqueous medium. Chemoselective removal of the benzyl group was achieved with excellent yields when secondary amines and alcohol moieties were also present.
- Martínez-Montero, Lía,Díaz-Rodríguez, Alba,Gotor, Vicente,Gotor-Fernández, Vicente,Lavandera, Iván
-
supporting information
p. 2794 - 2798
(2015/05/27)
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- An improved and efficient process for the scalable preparation of optically pure trans-2-aminocyclohexanols
-
An improved and efficient process has been developed for a green and scalable preparation of optically pure (1R,2R) - and (1S,2S) -trans-2-aminocyclohexanols. The process utilised hot water to promote the aminolysis of cyclohexene oxide by benzylamine to afford racemic trans-2-(benzylamino)cyclohexanols, which were resolved by sequential and repeated use of (R)- and (S)-mandelic acid. Finally, after treatment of the two salts sequentially with HCl and NaOH and recovery of mandelic acid, liberation was achieved of the optically pure trans-2-benzylaminoaminocyclohexanols which were smoothly debenzylated using a low loading of a Pd/C catalyst to the trans-2-aminocyclohexanols. The synthetic route has been successfully applied to large-scale (1 mol) preparations in good yield.
- Xue, Feng,Li, Chang-Gong,Zhu, Yong,Lou, Tian-Jun
-
p. 322 - 324
(2014/06/09)
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- N-Fluorobenzenaminium tetrafluoroborate generated in situ by aniline and Selectfluor as a reusable catalyst for the ring opening of epoxides with amines under microwave irradiation
-
The ring opening of epoxides with aromatic and aliphatic amines was carried out under solvent free conditions using N-fluorobenzenaminium tetrafluoroborate (2 mol%) generated in situ by the reaction of aniline and Selectfluor as a catalyst with microwave irradiation. Excellent yields of β-amino alcohols were obtained. The catalyst also results in the retention of the stereochemistry for the ring opening of enantiopure epoxide with amine. The catalyst was recovered and reused up to 4 cycles for the ring opening of cyclohexene oxide with aniline. This journal is
- Chauhan, Manmohan Singh,Yadav, Geeta Devi,Hussain, Firasat,Singh, Surendra
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p. 3945 - 3952
(2015/02/19)
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- CYCLOHEXANEDIAMINE COMPOUNDS AND METHODS FOR THEIR PREPARATION
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The present invention provides processes for the preparation of cyclohexanediamine compounds of formula Ia and intermediates thereof. The compounds are useful as Syk kinase inhibitors and in various pharmaceutical compositions, and particularly useful for treating conditions mediated at least in part by Syk kinase activity.
- -
-
Paragraph 0104; 0105
(2014/10/04)
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- Synthesis of (3RS,3aSR,8aSR)-3-phenyloctahydrocyclohepta[b]pyrrol-4(1H)-one via the aza-Cope-Mannich rearrangement
-
A convenient and scalable method for the preparation of (3RS,3aSR,8aSR)-phenyloctahydrocyclohepta[b]pyrrol-4(1H)-one based on the aza-Cope-Mannich rearrangement is described. This approach allows us to synthesize the target compound in nine steps in a high overall yield (42%) with complete stereocontrol and up to 100 g scale.
- Belov, Dmitry S.,Lukyanenko, Evgeny R.,Kurkin, Alexander V.,Yurovskaya, Marina A.
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scheme or table
p. 9214 - 9218
(2011/12/01)
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- Zinc tetrafluoroborate hydrate as a mild catalyst for epoxide ring opening with amines: Scope and limitations of metal tetrafluoroborates and applications in the synthesis of antihypertensive drugs (RS)/(R)/(S)-metoprolols
-
The scope and limitations of metal tetrafluoroborates have been studied for epoxide ring-opening reaction with amines, and Zn(BF4) 2?xH2O has been found to be a mild and efficient catalyst affording high yields under solvent-free conditions at rt with excellent chemo-, regio-, and stereoselectivities. The catalytic efficiency followed the order Zn(BF4)2?xH2O ? Cu(BF4)2?xH2O > Co(BF4) 2?6H2O ? Fe(BF4)2? 6H2O > LiBF4 for reactions with cyclohexene oxide and Zn(BF4)2?xH2O ? Co(BF4) 2?6H2O ? Fe(BF4)2? 6H2O > Cu(BF4)2?xH2O for stilbene oxide, but AgBF4 was ineffective. For reaction of styrene oxide with aniline, the metal tetrafluoroborates exhibited comparable regioselectivity (1:99-7:93) with preferential reaction at the benzylic carbon of the epoxide ring. A reversal of regioselectivity (91:1-69:31) in favor of the reaction at the terminal carbon of the epoxide ring was observed for reaction with morpholine. The regioselectivity was dependent on the electronic and steric factors of the epoxide and the pKa of the amine and independent of amine nucleophilicity. The role of the metal tetrafluoroborates is envisaged as "electrophile nucleophile dual activation" through cooperativity of coordination, charge-charge interaction, and hydrogen-bond formation that rationalizes the catalytic efficiency, substrate reactivity, and regioselectivity. The methodology was used for synthesis of cardiovascular drug metoprolol as racemic and enriched enantiomeric forms.
- Pujala, Brahmam,Rana, Shivani,Chakraborti, Asit K.
-
experimental part
p. 8768 - 8780
(2011/12/04)
-
- Thieme chemistry journal awardees-where are they now? bifunctional organocatalysis with N-Formyl-l-proline: A novel approach to epoxide ring opening and sulfide oxidation
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A conceptually distinct approach to the aminolysis of 1,2-epoxides, which involves Lewis base-Br?nsted acid catalysis employing N-formyl-l-proline as an easily accessible bifunctional organocatalyst and water as a solvent is presented. The potential of N-formyl-l-proline as organocatalyst for the sulfide oxidation reaction using aqueous hydrogen peroxide as environmentally benign and readily available oxidant is also demonstrated. Good to high yields are achieved for both reactions. Georg Thieme Verlag Stuttgart ? New York.
- Wei, Shengwei,Stingl, Kerstin A.,Wei?, Katharina M.,Tsogoeva, Svetlana B.
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experimental part
p. 707 - 711
(2010/06/13)
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- Microwave-enhanced bismuth triflate-catalyzed epoxide opening with aliphatic amines
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In the presence of a catalytic amount of Bi(OTf)3·4H2O and under microwave irradiation, neat mixtures of epoxides and amines afforded smoothly the corresponding 2-amino alcohols. A wide variety of aliphatic amines were reacted with cycloalkene oxide, styrene oxide, and stilbene oxide. The reaction proceeded rapidly and afforded the 2-amino alcohols in high up to quantitative yields. All products could be obtained without aqueous work-up by simple filtration.
- Ollevier, Thierry,Nadeau, Etienne
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p. 1546 - 1550
(2008/09/19)
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- Regioselective ring-opening of epoxides with amines using Zn(ClO4)2-Al2O3 as a heterogeneous and recyclable catalyst
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A simple and efficient method has been developed for the synthesis of β-amino alcohols by regioselective ring-opening of epoxides with amines in the presence of zinc perchlorate-neutral alumina as a heterogeneous recyclable catalyst at room temperature in high yields.
- Maheswara, Muchchintala,Rao, Kummari Subba Venkata Krishna,Do, Jung Yun
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p. 1795 - 1800
(2008/09/18)
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- Efficient ring opening of aziridines with carboxylic acids
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An efficient ring cleavage of aziridines with acids has been studied in the absence of any catalyst. The hydrolysis of the products, amino esters, leads to the corresponding amino alcohols. The reaction has been extended to chiral cycloalkyl aziridines, leading to the formation of diastereomers. After separation, these diastereomers have been converted to optically pure amino alcohols in two steps. Copyright Taylor & Francis Group, LLC.
- Kumar, Manoj,Gandhi, Shikha,Kalra, Swinderjeet Singh,Singh, Vinod K.
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p. 1527 - 1532
(2008/09/20)
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- Zinc(II) perchlorate hexahydrate catalyzed opening of epoxide ring by amines: Applications to synthesis of (RS)/(R)-propranolols and (RS)/(R)/(S)-naftopidils
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(Figure Presented) Commercially available zinc(II) Perchlorate hexahydrate [Zn(ClO4)2·6H2O] was found to be a new and highly efficient catalyst for opening of epoxide rings by amines affording 2-amino alcohols in high yields under solvent-free conditions and with excellent chemo-, regio-, and stereoselectivities. For unsymmetrical epoxides, the regioselectivity was influenced by the electronic and steric factors associated with the epoxides and the amines. A complementarity in the regioselectivity was observed during the reaction of styrene oxide with aromatic and aliphatic amines: aromatic amines provided amino alcohols from nucleophilic attack at the benzylic carbon as major products whereas aliphatic amines resulted in formation of the amino alcohols through reaction at the terminal carbon atom of the epoxide ring as the major/sole products. Reaction of aniline with various glycidic ethers gave the amino alcohols by regioselective nucleophilic attack at the terminal carbon atom of the epoxide ring as the only/major product. Zinc(II) Perchlorate hexahydrate was found to be the best catalyst compared to other metal Perchlorates. The counteranion modulated the catalytic property of the various Zn(II) compounds that followed the order Zn(ClO4) 2·6H2O Zn(BF4)2 ~ Zn(OTf)2 ZnI2 > ZnBr2 > ZnCl2 > Zn(OAc)2 > Zn(CO3)2 in parallelism with the acidic strength of the corresponding protic acids (except for TfOH). The applicability of the methodology was demonstrated by the synthesis of cardiovascular drugs propranolol and naftopidil as racemates and optically active enantiomers.
- Shivani,Pujala, Brahmam,Chakraborti, Asit K.
-
p. 3713 - 3722
(2008/02/05)
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- 2-(CYCLIC AMINO)-PYRIMIDONE DERIVATIVES AS TPK1 INHIBITORS
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A compound represented by the formula (I), an optically active isomer thereof, or a pharmaceutical acceptable salt thereof (I) wherein R2 represents a hydrogen or the like; R3 represents methyl group or the like; R20 represents a halogen atom or the like; q represents an integer of 0 to 3; Z represent nitrogen atom, CH, or the like; R4 represents hydrogen or the like; R5 represents hydrogen or the like; R6 represents a substituted alkyloxy and the like; p represents an integer of 0 to 3; X represents bond, CH2, oxygen atom, NH, or the like; any one or more of R5 and R6, R5 and R4, R6 and R4, X and R5, X and R4, X and R6, and R6 and R6 may combine to each other to form a ring, which is used for preventive and/or therapeutic treatment of a disease caused by tau protein kinase 1 hyperactivity such as a neurodegenerative diseases (e.g. Alzheimer disease).
- -
-
Page/Page column 199
(2008/06/13)
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- Solid lithium perchlorate as a powerful catalyst for the synthesis of β-aminoalcohols under solvent-free conditions
-
Lithium perchlorate catalyzed the ring opening of epoxides with amines to provide the corresponding β-aminoalcohols in excellent yields with high regioselectivity. The reaction proceeds rapidly under mild and neutral conditions and worked well with primary, secondary, aliphatic, aromatic, and hindered amines in short times at room temperature, in the absence of solvent.
- Azizi, Najmodin,Saidi, Mohammad R.
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p. 505 - 507
(2007/10/03)
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- Scandium triflate as an efficient and useful catalyst for the synthesis of β-amino alcohols by regioselective ring opening of epoxides with amines under solvent-free conditions
-
A simple and efficient method has been developed for the synthesis of β-amino alcohols by ring opening of epoxides in the presence of a catalytic amount of Sc(OTf)3 at room temperature under solvent-free conditions. The reaction works well with both aromatic and aliphatic amines. High regio-, and diastereoselectivity can be considered as a noteworthy advantage of this method.
- Placzek, Andrew T.,Donelson, James L.,Trivedi, Rushi,Gibbs, Richard A.,De, Surya K.
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p. 9029 - 9034
(2007/10/03)
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- Lithium bromide, an inexpensive and efficient catalyst for opening of epoxide rings by amines at room temperature under solvent-free condition
-
Lithium bromide has been found to be an inexpensive and efficient catalyst for the opening of epoxide rings by amines, and this provides an environmentally friendly method for the synthesis of β-amino alcohols. Aromatic and aliphatic amines react with cycloalkene oxides to exclusively form trans-2-(aryl/alkylamino)cycloalkanols in high yields. A 98-100% selectivity in favour of nucleophilic attack at the benzylic carbon atom of styrene oxide is observed with aromatic amines. However, aliphatic amines exhibit a marginal preference for the reaction at the terminal carbon atom of the epoxide ring in styrene oxide. Non-styrenoidal, unsymmetrical alkene oxides undergo selective nucleophilic attack at the sterically less hindered carbon atom by aniline. The chelation effect of the Li+ ion enables selective opening of the epoxide ring in 3-phenoxypropylene oxide in the presence of styrene oxide. Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004.
- Chakraborti, Asit K.,Rudrawar, Santosh,Kondaskara, Atul
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p. 3597 - 3600
(2007/10/03)
-
- Scope and limitations of montmorillonite K 10 catalysed opening of epoxide rings by amines
-
Montmorillonite K 10 efficiently catalyses the opening of epoxide rings by amines in high yields with excellent regio- and diastereo-selectivities under solvent-free conditions at room temperature affording an improved process for synthesis of 2-amino alcohols. Reaction of cyclohexene oxide with aryl/alkyl amines leads to the formation of trans-2-aryl/alkylaminocyclohexanols. For unsymmetrical epoxides, the regioselectivity is controlled by the electronic and steric factors associated with the epoxide and the amine. Selective nucleophilic attack at the benzylic carbon of styrene oxide takes place with aromatic amines, whereas, aliphatic amines exhibit preferential nucleophilic attack at the terminal carbon. Aniline reacts selectively at the less hindered carbon of other unsymmetrical epoxides. The difference in the internal strain energy of the epoxide ring in cycloalkene oxides and alkene oxides led to selective nucleophilic opening of cyclohexene oxide by aniline in the presence of styrene oxide. Due to the chelation effect, selective activation of the epoxide ring in 3-phenoxy propylene oxide takes place in the presence of styrene oxide leading to preferential cleavage of the epoxide ring in 3-phenoxy propylene oxide by aniline.
- Chakraborti, Asit K.,Kondaskar, Atul,Rudrawar, Santosh
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p. 9085 - 9091
(2007/10/03)
-
- ZrCl4 as a new and efficient catalyst for the opening of epoxide rings by amines
-
Zirconium(IV) chloride catalyses the nucleophilic opening of epoxide rings by amines leading to the efficient synthesis of β-amino alcohols. The reaction works well with aromatic and aliphatic amines in short times at room temperature in the absence of solvent. Exclusive trans stereoselectivity is observed for cyclic epoxides. Aromatic amines exhibit excellent regioselectivity for preferential nucleophilic attack at the sterically less hindered position during the reaction with unsymmetrical epoxides. However, in case of styrene oxide, selective formation of the benzylic amine was observed during the reactions with aromatic amines.
- Chakraborti, Asit K.,Kondaskar, Atul
-
p. 8315 - 8319
(2007/10/03)
-
- Calcium trifluoromethanesulfonate-catalysed aminolysis of epoxides
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Aminolysis of epoxides catalysed by calcium trifluoromethanesulfonate under mild reaction conditions is described. The novel method is very efficient in the synthesis of wide variety of β-amino alcohols with high regio- and stereoselectivity.
- Cepanec, Ivica,Litvi?, Mladen,Mikulda?, Hrvoje,Bartolin?i?, Anamarija,Vinkovi?, Vladimir
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p. 2435 - 2439
(2007/10/03)
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- Efficient ring-opening reaction of epoxides and aziridines promoted by tributylphosphine in water
-
Tributylphosphine was found to be an effective promoting reagent for the ring-opening reaction of various epoxides and aziridines with nucleophile to produce corresponding anti-bifunctional products in moderate to excellent yields in water.
- Fan, Ren-Hua,Hou, Xue-Long
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p. 726 - 730
(2007/10/03)
-
- Ring-opening reactions of nonactivated aziridines catalyzed by tris(pentafluorophenyl)borane
-
The ring-opening reactions of nonactivated aziridines with amine nucleophiles are efficiently catalyzed by tris(pentafluorophenyl)borane leading to derivatives of trans-1,2-diamines in high yields. A mechanistic investigation of the reaction suggests that in situ formed [(C6F5)3B(OH2)]· H2O catalyzes the opening through a Bronsted acid manifold.
- Watson, Iain D. G.,Yudin, Andrei K.
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p. 5160 - 5167
(2007/10/03)
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- Zinc-catalyzed aminolysis of epoxides
-
A series of amino alcohols has been prepared by a novel zinc-catalyzed nucleophilic opening of epoxide rings by amines.
- Pachón, Laura Durán,Gamez, Patrick,Van Brussel, Jos J. M.,Reedijk, Jan
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p. 6025 - 6027
(2007/10/03)
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- Preparation of trans-1,2-diaminocyclohexane derivatives by lithium perchlorate catalyzed ring opening of aziridines
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N,N′-Dialkylated trans-1,2-diaminocyclohexane derivatives were synthesized with good overall yield via reaction of the corresponding N-alkylated cyclohexene aziridine with amines, in the presence of lithium perchlorate as catalyst.
- De Parrodi,Vazquez,Quintero,Juaristi
-
p. 3295 - 3302
(2007/10/03)
-
- Diisopropoxyaluminium trifluoroacetate: A new promoter for aminolysis of epoxides
-
Aminolysis of symmetrical as well as unsymmetrical epoxides using various amines in the presence of diisopropoxyaluminium trifluoroacetate (DIPAT) as a new promoter gave 1,2-amino alcohols in excellent yields at room temperature with good to excellent selectivities.
- Rampalli, Sriram,Chaudhari, Sachin S.,Akamanchi, Krishnacharya G.
-
-
- Synthesis and conformational study of stereoisomeric 2-phenyl-4a,5,6,7,8,8a-hexahydro-4H-1,3,4-benzoxadiazines
-
The synthesis and conformational behaviour of some new cis- and trans-fused N4-R-2-phenyl-4a,5,6,7,8,8a-hexahydro-4H-1,3,4-benzoxadiazines are described. Their vicinal coupling constants reveal that the trans-fused isomers adopt an anancomeric chair-(half-chair) conformation, whereas the cis-fused isomers exist in a conformational equilibrium of the O-in (having the oxygen attached axially to the cyclohexyl ring) and O-out conformers. At room temperature, the O-in conformers slightly predominate, as estimated from the vicinal coupling constants. However, only a rough estimation, especially in the cis N-CH2Ph derivative 9a, can be made of the conformational equilibria due to an obvious deformation of the carbocyclic ring (a flattened, non-ideal chair conformation), making the selection of model 3JH,H values difficult. At 193 K the O-in conformer predominates in a ratio of 85:15 for the cis N-CH2Ph derivative and 70:30 for the cis N-Me derivative, estimated from the 13C signal integrals of both cis conformers, as they separated in low-temperature experiments (193 K).
- Rosling, Ari,Fueloep, Ferenc,Askolin, Curt-Peter,Mattinen, Jorma
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p. 2237 - 2250
(2007/10/03)
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- Synthesis of 6-amino-3,5-deoxyinositol 1-phosphates via (1R,2R,4R,6S)- 1,6-epoxy-2,4-bis-benzyloxycyclohexane aminolysis in aqueous ytterbium triflate solution
-
(1R,2R,4R,6S)-1,6-Epoxy-2,4-bis-benzyloxycyclohexane was prepared from (-)-quinic acid and this, and cyclohexene oxide, were treated with various N- nucleophiles under a variety of conditions. In aqueous solution containing catalytic amounts of ytterbium (III) triflate, ammonia and alkylamines reacted smoothly to give the required trans-1,2-amino alcohols in quantitative recovery. Conversion of the 6-amino-2,4-bis-benzyloxycyclohexan- 1-ols to 6-amino-1,2,4-trihydroxycyclohexane 1-phosphates, probes for the mechanism of inositol monophosphatase, was achieved in good overall yield.
- Beaton, Martin,Gani, David
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p. 8549 - 8552
(2007/10/03)
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- Preparation of 2-oxazolidinones by intramolecular nucleophilic substitution
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Treatment of N-alkoxycarbonyl, N-benzyl protected β-amino alcohols with triphenylphosphine and hexachloroethane in 1,2-dichloroethane induces cyclization to 2-oxazolidinones, which are formed by intramolecular attack with inversion of configuration at the secondary alcohol. In contrast, mono N-substituted alkyl carbamates undergo chlorination under the same conditions.
- Van Delft, Floris L.,Timmers, Cornelis M.,Van Der Marel, Gijs A.,Van Boom, Jacques H.
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p. 450 - 454
(2007/10/03)
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- Ytterbium Triflate and High Pressure-mediated Ring Opening of Epoxides with Amines
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Ring opening of epoxides with amines in THF takes place very readily in the presence of catalytic amounts of ytterbium triflate to give the corresponding β-amino alcohols in good to high yields.With tri- and tetra-substituted epoxides, the use of an excess (2 - 3 equiv.) of the amine is needed.The Yb(OTf)3-catalysed reaction of epoxides with amines in CH2Cl2 is quite complex; the yield of amino alcohols is generally lower and depends upon the addition order of the catalyst, amine and epoxide.The ring opening is accomplished also under high pressures in the absence of Yb(OTf)3.Ring opening with a combination of Yb(OTf)3 in CH2Cl2 and high pressure is more effective than the use, independently, of either Yb(OTf)3 or the high-pressure method.Oxetanes and β-lactones undergo ring opening in the presence of Yb(OTf)3.
- Meguro, Masaki,Asao, Naoki,Yamamoto, Yoshinori
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p. 2597 - 2602
(2007/10/02)
-
- Syntheses and X-Ray Crystal Structures of Tricyclic Ketones Containing Trans-Fused Azabicyclooctane Units
-
Tricyclic ketones containing the trans-fused 3-azabicyclooctane framework were prepared from the reactions of dienes and Cp2ZrBu2, followed by treatment with carbon monoxide.The structures were confirmed by X-ray analysis.
- Mori, Miwako,Saitoh, Fumihiko,Uesaka, Noriaki,Okamura, Kimio,Date, Tadamasa
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p. 4993 - 4998
(2007/10/02)
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- Regio- and Stereo-selective Ring Opening of Epoxides with Amide Cuprate Reagents
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Amide cuprate reagents attack the less hindered carbon atom of epoxides to give 1,2-amino alcohols in good yields; this procedure is applied to the synthesis of an aziridine alcohol bearing a carborane framework which is a potentially useful 10B carrier for boron neutron capture therapy.
- Yamamoto, Yoshinori,Asao, Naoki,Meguro, Masaki,Tsukada, Naofumi,Nemoto, Hisao,et al.
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p. 1201 - 1203
(2007/10/02)
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- Metal salts as new catalysts for mild and efficient aminolysis of oxiranes
-
A new, simple, efficient, inexpensive, anti stereoselective, highly regioselective method for aminolysis of 1,2-epoxides, by means of metal salts, is described.
- Chini,Crotti,Macchia
-
p. 4661 - 4664
(2007/10/02)
-
- TETRAPHENYLSTIBONIUM TRIFLATE AS A REGIO- AND CHEMOSELECTIVE CATALYST IN THE REACTION OF OXIRANES WITH AMINES
-
Tetraphenylstibonium triflate catalytically promotes the nucleophilic addition of amines to oxiranes under mild conditions, giving the corresponding β-amino alcohols regio- and chemoselectively.
- Fujiwara, Masahiro,Imada, Makoto,Baba, Akio,Matsuda, Haruo
-
p. 739 - 742
(2007/10/02)
-
- AMINOLEAD COMPOUNDS AS A NEW REAGENT FOR REGIOSELECTIVE RING OPENING OF EPOXIDES
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Regioselective ring opening of epoxides is accomplished by using aminolead compounds; the reagents attack the less hindered carbon of epoxide ring, and the amino alcohols are obtained in good yields.
- Yamada, Jun-ichi,Yumoto, Masatoshi,Yamamoto, Yoshinori
-
p. 4255 - 4258
(2007/10/02)
-