- NICKEL-CATALYZED OLIGOMERIZATION OF FUNCTIONALIZED CONJUGATED DIENES
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The cyclodimerization of several functionalized dienes with nickel(0) catalysts has been studied.When a functional group, such as a methoxycarbonyl or a trimethylsiloxy group, is bonded directly to the terminal carbon of the diene grouping, a completely regio- and stereo-selective dimerization is observed and trans-1,2-disubstituted cycloocta-3,7-dienes are formed in good yields (80-90percent).When one carbon atom separates the functional group from the diene group, the yield drops significantly (to 30percent), and the stereoselectivity and the clean nature of the reaction are completely lost.The effect of the nature of the nickel catalyst and the influence of the reductive organoaluminum species are discussed.The particular structure and the stereochemical features of the cyclooctadiene derivatives allow a better understanding of the various steps involved in the catalytic process.A reaction mechanism is proposed.
- Tenaglia, A.,Brun, P.,Waegell, B.
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- Photochirogenic nanosponges: phase-controlled enantiodifferentiating photoisomerization of (Z)-cyclooctene sensitized by pyromellitate-crosslinked linear maltodextrin
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Linear maltodextrin (LM) was cross-linked by pyromellitic dianhydride to afford LM polymers of different cross-linking degrees. When soaked in water, these cross-linked LM polymers (nanosponges (NSs)), evolved into several phases from sol to suspension, then to flowing gel, and finally to rigid gel with an increase in their content. Enantiodifferentiating photoisomerization of (Z)-cyclooctene (1Z) to chiral (E)-isomer (1E), which was employed as a benchmark reaction to quantitatively assess the environmental-to-molecular chirality transfer process, was performed in aqueous media containing these pyromellitate-crosslinked LM-NSs in different phases. The enantiomeric excess (ee) of 1E obtained was relatively insensitive to the phases at least up to the flowing gel phase, but became highly sensitive in the rigid gel phase, exhibiting an abrupt drop in the early rigid gel phase followed by a rapid recovery in the late rigid gel phase. A comparison with the phase-dependent ee profiles previously reported for similar pyromellitate-crosslinked cyclodextrin (CD)- and cyclic nigerosylnigerose (CNN)-NSs revealed that the chiral void space created around the pyromellitate linker in NS is responsible for the dramatic changes in ee in the rigid gel phase, whereas the inherent host cavity in CD/CNN plays only limited roles in the supramolecular photochirogenesis mediated by the sensitizer-crosslinked NSs. The latter insight allows us to further expand the applicable range of the present concept and methodology by employing a much wider variety of oligosaccharides as well as substrates and sensitizing cross-linkers.
- Liang, Wenting,Zhao, Meiling,Wei, Xueqin,Yan, Zhiqiang,Wu, Wanhua,Caldera, Fabrizio,Trotta, Francesco,Inoue, Yoshihisa,Su, Dan,Zhong, Zhihui,Yang, Cheng
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p. 17184 - 17192
(2017/03/30)
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- Hydrogen Bonding-Assisted Enhancement of the Reaction Rate and Selectivity in the Kinetic Resolution of d,l-1,2-Diols with Chiral Nucleophilic Catalysts
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An extremely efficient acylative kinetic resolution of d,l-1,2-diols in the presence of only 0.5 mol% of binaphthyl-based chiral N,N-4-dimethylaminopyridine was developed (selectivity factor of up to 180). Several key experiments revealed that hydrogen bonding between the tert-alcohol unit(s) of the catalyst and the 1,2-diol unit of the substrate is critical for accelerating the rate of monoacylation and achieving high enantioselectivity. This catalytic system can be applied to a wide range of substrates involving racemic acyclic and cyclic 1,2-diols with high selectivity factors. The kinetic resolution of d,l-hydrobenzoin and trans-1,2-cyclohexanediol on a multigram scale (10 g) also proceeded with high selectivity and under moderate reaction conditions: (i) very low catalyst loading (0.1 mol%); (ii) an easily achievable low reaction temperature (0 °C); (iii) high substrate concentration (1.0 M); and (iv) short reaction time (30 min). (Figure presented.).
- Fujii, Kazuki,Mitsudo, Koichi,Mandai, Hiroki,Suga, Seiji
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supporting information
p. 2778 - 2788
(2017/08/23)
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- Alcohol cross-coupling for the kinetic resolution of diols via oxidative esterification
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We present an organocatalytic C-O-bond cross-coupling strategy to kinetically resolve racemic diols with aromatic and aliphatic alcohols, yielding enantioenriched esters. This one-pot protocol utilizes an oligopeptide multicatalyst, m-CPBA as the oxidant, and N,N-diisopropylcarbodiimide as the activating agent. Racemic acyclic diols as well as trans-cycloalkane-1,2-diols were kinetically resolved, achieving high selectivities and good yields for the products and recovered diols.
- Hofmann, Christine,Schümann, Jan M.,Schreiner, Peter R.
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p. 1972 - 1978
(2015/02/19)
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- En route to multicatalysis: Kinetic resolution of trans-cycloalkane-1,2- diols via oxidative esterification
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We demonstrate the application of a multicatalyst to the oxidation of a broad variety of aldehydes and subsequent enantioselective esterification of the incipient acids with (±)-trans-cycloalkane-1,2-diols. This reaction operates well with a multicatalyst bearing two independent catalytic moieties that provide monoprotected 1,2-diols in one pot.
- Hofmann, Christine,Schuler, Soeren M. M.,Wende, Raffael C.,Schreiner, Peter R.
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supporting information
p. 1221 - 1223
(2014/01/17)
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- Enantioselective biooxidation of racemic trans-cyclic vicinal diols: One-pot synthesis of both enantiopure (S,S)-cyclic vicinal diols and (R)-α-hydroxy ketones
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Highly regio- and enantioselective alcohol dehydrogenases BDHA (2,3-butanediol dehydrogenase from Bacillus subtilis BGSC1A1), CDDHPm (cyclic diol dehydrogenase from Pseudomonas medocina TA5), and CDDHRh (cyclic diol dehydrogenase from Rhodococcus sp. Moj-3449) were discovered for the oxidation of racemic trans-cyclic vicinal diols. Recombinant Escherichia coli expressing BDHA was engineered as an efficient whole-cell biocatalyst for the oxidation of (±)-1,2-cyclopentanediol, 1,2-cyclohexanediol, 1,2-cycloheptane-diol, and 1,2-cyclooctanediol, respectively, to give the corresponding (R)-α-hydroxy ketones in >99% ee and (S,S)-cyclic diols in >99% ee at 50% conversion in one pot. Escherichia coli (BDHA-LDH) co-expressing lactate dehydrogenase (LDH) for intracellular regeneration of NAD+ catalyzed the regio- and enantioselective oxidation of (±)-1,2-dihydroxy-1,2,3,4- tetrahydronaphthalene to produce the corresponding (R)-α-hydroxy ketone in >99% ee and (S,S)-cyclic diol in 96% ee at 49% conversion. Preparative biotransformations were also demonstrated. Thus, a novel and useful method for the one-pot synthesis of both vicinal diols and α-hydroxy ketones in high ee was developed via high Copyright
- Zhang, Jiandong,Xu, Tingting,Li, Zhi
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supporting information
p. 3147 - 3153
(2013/12/04)
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- Enhanced rate and selectivity by carboxylate salt as a basic cocatalyst in chiral N-heterocyclic carbene-catalyzed asymmetric acylation of secondary alcohols
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The rate and enantioselectivity of chiral NHC-catalyzed asymmetric acylation of alcohols with an adjacent H-bond donor functionality are remarkably enhanced in the presence of a carboxylate cocatalyst. The degree of the enhancement is correlated with the basicity of the carboxylate. With a cocatalyst and a newly developed electron-deficient chiral NHC, kinetic resolution and desymmetrization of cyclic diols and amino alcohols were achieved with extremely high selectivity (up to s = 218 and 99% ee, respectively) at a low catalyst loading (0.5 mol %). This asymmetric acylation is characterized by a unique preference for alcohols over amines, which are not converted into amides under the reaction conditions.
- Kuwano, Satoru,Harada, Shingo,Kang, Bubwoong,Oriez, Raphael,Yamaoka, Yousuke,Takasu, Kiyosei,Yamada, Ken-Ichi
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supporting information
p. 11485 - 11488
(2013/09/02)
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- Enantiomerically enriched trans-diols from alkenes in one pot: A multicatalyst approach
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Multicatalysts consisting of non-natural oligopeptides with distinctly different catalytic moieties create molecular complexity in a multistep one-pot sequence starting from simple alkenes yielding highly enantiomerically enriched trans-diols. The Royal Society of Chemistry 2012.
- Hrdina, Radim,Mueller, Christian E.,Wende, Raffael C.,Wanka, Lukas,Schreiner, Peter R.
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supporting information; experimental part
p. 2498 - 2500
(2012/04/10)
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- Bronsted acid-catalyzed dihydroxylation of olefins in aqueous medium
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The trans-dihydroxylation of olefins occurs efficiently by aqueous hydrogen peroxide catalyzed by p-toluenesulfonic acid at 50°C, allowing the catalyst reuse and an outstanding substrate functional group tolerance such as tert-butoxycarbonylamino (BocNH), benzyloxycarbonylamino (CbzNH), benzyloxy (OBn), tosyloxy (OTs), hindered ketal, (2-trimethylsilyl)ethoxymethoxy (OSEM), benzylamino (NBz), benzyloxy (OBz) and free amino acid. Copyright
- Rosatella, Andreia A.,Afonso, Carlos A.M.
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supporting information; experimental part
p. 2920 - 2926
(2012/01/03)
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- Kinetic resolution of trans-cycloalkane-1,2-diols via Steglich esterification
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We describe the efficient and highly enantioselective kinetic resolution of trans-cycloalkane-1,2-diols utilizing an enantioselective Steglich reaction with a variety of carboxylic acids that form the corresponding anhydrides in situ.
- Hrdina, Radim,Mueller, Christian E.,Schreiner, Peter R.
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supporting information; experimental part
p. 2689 - 2690
(2010/07/08)
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- Enantioselective kinetic resolution of trans-cycloalkane-1,2-diols
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Finally! The title resolution is achieved with a nonnatural, partially rigid, lipophilic tetrapeptide at low catalyst loadings without additional base or cosolvents. The transition-state model (ball-and-stick model in the scheme; C gray, N blue, O red) emphasizes the interplay between hydrogen-bonding and hydrophobic interactions. (Chemical Equation Presented)
- Mueller, Christian E.,Wanka, Lukas,Jewell, Kevin,Schreiner, Peter R.
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supporting information; body text
p. 6180 - 6183
(2009/04/06)
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- NaIO4/LiBr-mediated diastereoselective dihydroxylation of olefins: A catalytic approach to the prevost-woodward reaction
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(Chemical Equation Presented) LiBr catalyzes efficiently the dihydroxylation of alkenes to afford syn and anti diols with excellent diastereoselectivity depending upon the use of NaIO4 (30 mol %) or PhI(OAc)2 (1 equiv), respectively, as the oxidants. The oxidation of non-benzylic halides has been achieved for the first time to afford the corresponding diols in excellent yields.
- Emmanuvel, Lourdusamy,Ali Shaikh, Tanveer Mahammad,Sudalai, Arumugam
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p. 5071 - 5074
(2007/10/03)
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- Efficient photocatalytic oxidation of cycloalkenes by dihydroxo(tetraphenylporphyrinato)-antimony supported on silica gel under visible light irradiation
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In order to develop a photocatalyst operating under visible light irradiation, silica gel-supported dihydroxo(tetraphenylporphyrinato)antimony (V) complex, [SbTPP(OH)2]+/SiO2, was prepared. The photocatalytic oxidation of cycloalkenes with oxygen molecule was performed on [SbTPP(OH)2]+/SiO2 particles under irradiation of fluorescent light. The photocatalytic oxidation of cycloalkenes gave the corresponding cis-1,2-epoxycycloalkane, 2-cycloalkene-1-ol, and trans-1,2-cycloalkanediol.
- Shiragami, Tsutomu,Makise, Ryu-Ichi,Inokuchi, Yousuke,Matsumoto, Jin,Inoue, Haruo,Yasuda, Masahide
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p. 736 - 737
(2007/10/03)
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- Non-heme iron complexes for stereoselective oxidation: Tuning of the selectivity in dihydroxylation using different solvents
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A new class of functional models for non-heme iron-based dioxygenases, including [(N3Py-Me)Fe(CH3CN)2](ClO4) 2 and [(N3Py-Bn)Fe(CH3CN)2](ClO 4)2 {N3Py-Me = [di(2-pyridyl)methyl]methyl(2-pyridyl) methylamine; N3Py-Bn = [di(2-pyridyl)methyl]benzyl(2-pyridyl)methylamine}, is presented here. NMR, UV and X-ray analyses revealed that six-coordinate low-spin FeII complexes with the pyridine N-atoms and the tertiary amine functionality of the ligand bound to Fe are formed. The two remaining coordination sites located cis to each other are occupied by labile CH 3CN groups that are easily exchanged by other ligands. We demonstrate that the reactivity and stereoselectivity of the complexes investigated depend on the choice of the solvent. The complexes have been examined as catalysts for the oxidation of both alkanes and olefins in CH3CN. In this solvent alkanes are oxidized to alcohols and ketones and olefins to the corresponding cis-epoxides and cis-diols. In acetone as solvent a different reactivity pattern was found, with, as the most striking example, the trans-dihydroxylation of cis-olefins. 18O-labeling studies in CH3CN establish incorporation of 18O from H218O2 and H218O in both the epoxide and the diol implicating an HO-FeV=18O active intermediate originating from an H 218O-FeIIIOOH species. These results are in full agreement with mechanistic schemes derived for other dioxygenase model systems. Based on labeling studies in acetone an additional oxidation mechanism is proposed for this solvent, in which the solvent acetone is involved. This is the first example of a catalyst that can give cis- or trans-dihydroxylation products, just by changing the solvent. Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004.
- Klopstra, Marten,Roelfes, Gerard,Hage, Ronald,Kellogg, Richard M.,Feringa, Ben L.
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p. 846 - 856
(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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- Phenyl sulphonyl acetaldehyde diethyl acetal: A new robust 1,2-diol protective group
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A simple preparation of a novel resilient protective group for 1,2-diols is described herein which is remarkably stable in the presence of extremely harsh basic conditions as well as acidic media. The title reagent's versatility is detailed with numerous examples.
- Chandrasekhar,Srinivas, Ch.,Srihari
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p. 895 - 902
(2007/10/03)
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- Bromoacetone: A new protective group for 1,2-diols cleavable with zinc
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Bromoacetone has been utilized for the first time as an excellent protective group for 1,2-diols that can be cleaved under neutral conditions viz., refluxing in Zn-MeOH.
- Chandrasekhar,Srinivas,Suresh Kumar,Muralidhar
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p. 1147 - 1152
(2007/10/03)
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- Synthesis of optically active bicyclo[3.3.0]octane Skeleton using transannular reaction
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Optically active 5-cyclooctene-1,2-diol derivatives prepared by an enzymatic procedure have been converted into bicyclo[3.3.0]octane derivatives by transannular reaction with complete inversion of the stereogenic center linked to the leaving group. Formal synthesis of (+)-iridomyrmecin has been achieved starting from (S,S)-5-cyclooctene-1,2-diol by using this process.
- Horikawa, Tamaki,Norimine, Yoshihiko,Tanaka, Masakazu,Sakai, Kiyoshi,Suemune, Hiroshi
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- Pinacol Coupling of Aliphatic Aldehydes Promoted by Niobium (III) Reagent
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NbCl3 (DME) was found to be a useful reagent for the intermolecular pinacol coupling of aliphatic aldehydes.The high anti diastereoselectivity of this reaction (dl / meso >/= 9 / 1) did not depend on the variation in the aldehyde alkyl chain.With respect to intramolecular pinacolization, the loss of the stereoselectivity observed is consistent with the mechanism involving an insertion of the oxo-group into the metal-carbon bond of the intermediate niobiooxirane. - Key Words: Nb(III) reagent; Pinacol coupling; Acetalization; Stereoselectivity
- Szymoniak, Jan,Besancon, Jack,Moise, Claude
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p. 2841 - 2848
(2007/10/02)
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- Oxidation of Alkenes with Aqueous Potassium Peroxymonosulfate and No Organic Solvent
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Aqueous potassium peroxymonosulfate oxidizes water-immiscible alkenes at room temperature in the absence of organic solvent.Acidic (pH 6.7 with NaHCO3 enabled selective epoxidations of 2,3-dimethyl-2-butene, 1-methylcyclohexene, cyclohexene, styrene, and β-methylstyrene.The order of decreasing reactivity of alkenes was: 2,3-dimethyl-2-butene > 1-methylcyclohexene cyclohexene > cyclooctene > α-methylstyrene β-methylstyrene > styrene > p-methylstyrene > allylbenzene. 1-Octene and tetrachloroethylene did not react.Phase-transfer catalysts, a colloidal cationic polymer, and a cationic surfactant microemulsion had little effect on the reaction.
- Zhu, Weiming,Ford, Warren T.
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p. 7022 - 7026
(2007/10/02)
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- SYNTHESIS OF 1,2-CYCLOALKANEDIOLS BY INTRAMOLECULAR TITANIUM-INDUCED PINACOL COUPLING
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Seven representative 1,2-cycloalkanediols of ring size 6-14 were prepared in high yield by titanium-induced pinacol coupling of dialdehydes.Cis stereochemistry predominated in six- and eight-membered rings, but trans products were formed in ring sizes ten and above.
- McMurry, John E.,Rico, Joseph G.
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p. 1169 - 1172
(2007/10/02)
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- REGIO AND STEREO SELECTIVE SYNTHESIS OF DISUBSTITUTED CYCLOOCTADIENES.
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Functionalized dienes can be dimerized in the presence of Ni(o) catalyst in order to afford regio and stereo selectively 1,2-trans disubstituted 3,7-cyclooctadiene derivatives.
- Brun, P.,Tenaglia, A.,Waegell, B.
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p. 385 - 388
(2007/10/02)
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