- Copper-catalyzed enantioselective synthesis of bridged bicyclic ketals from 1,1-disubstituted-4-methylene-1,6-hexanediols and related alkenols
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Bridged bicyclic ketals display a range of bioactivities. Their catalytic enantioselective synthesis from acyclic 1,1-disubstituted alkene diols is disclosed. This reaction combines asymmetric catalysis with a distal radical migration. Alkynes and arenes
- Burde, Ameya S.,Karyakarte, Shuklendu D.,Sylvester, Eric D.,Chemler, Sherry R.
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supporting information
p. 105 - 108
(2021/01/14)
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- Selective hydroboration of equilibrating allylic azides
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The iridium(i)-catalyzed hydroboration of equilibrating allylic azides is reported to provide only the anti-Markovnikov product of alk-1-ene isomers in good yields and with good functional group tolerance.
- Liu, Ruzhang,Xu, Jun,Zhang, Yuanyuan
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supporting information
p. 8913 - 8916
(2021/09/13)
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- Catalytic Acceptorless Dehydrogenation of Aliphatic Alcohols
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We developed the first acceptorless dehydrogenation of aliphatic secondary alcohols to ketones under visible light irradiation at room temperature by devising a ternary hybrid catalyst system comprising a photoredox catalyst, a thiophosphate organocatalyst, and a nickel catalyst. The reaction proceeded through three main steps: hydrogen atom transfer from the α-C-H bond of an alcohol substrate to the thiyl radical of the photo-oxidized organocatalyst, interception of the generated carbon-centered radical with a nickel catalyst, and β-hydride elimination. The reaction proceeded in high yield under mild conditions without producing side products (except H2 gas) from various alcohols, including sterically hindered alcohols, a steroid, and a pharmaceutical derivative. This catalyst system also promoted acceptorless cross-dehydrogenative esterification from aldehydes and alcohols through hemiacetal intermediates.
- Fuse, Hiromu,Mitsunuma, Harunobu,Kanai, Motomu
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supporting information
p. 4493 - 4499
(2020/03/05)
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- Protecting-group-free synthesis of hydroxyesters from amino alcohols
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The synthesis of hydroxyesters from carboxylic acids and unprotected amino alcohols in both continuous flow and batch processes is reported. The formation of a transient diazonium species with a dinitrite reagent is key in this transformation. The reaction conditions are compatible with a variety of functional groups.
- Joseph-Valcin, Eve-Marline,Lebel, Hélène,Reynard, Guillaume
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supporting information
p. 10938 - 10941
(2020/10/02)
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- Bisnucleophilic substitution as a synthetic tool for ready access to the piperidine alkaloids (+)-Connine, (+)-β-conhydrine, (+)-8-ethylnorlobelol, and (-)-halosaline
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Herein we report the stereoselective total synthesis of (+)-connine, (+)-β-conhydrine, (+)-8-ethylnorlobelol, and (-)-halosaline via bisnucleophilic substitution with benzylamine as the key step.
- Raju, Galla,Anitha, Kadimi,Krishna, Palakodety Radha
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p. 937 - 941
(2015/04/27)
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- Copper(I)-catalyzed enantioselective nucleophilic borylation of aldehydes: An efficient route to enantiomerically enriched α-alkoxyorganoboronate esters
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The first catalytic enantioselective nucleophilic borylation of a
- Kubota, Koji,Yamamoto, Eiji,Ito, Hajime
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supporting information
p. 420 - 424
(2015/01/30)
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- Mild deprotection of PMB ethers using tert-butyl bromide
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A convenient and high yielding method for the cleavage and scavenging of p-methoxybenzyl protecting group of several alcohols using tert-butyl bromide in refluxing acetonitrile is described. Under these mild conditions other protecting groups such as acid sensitive allyl, benzyl, and Me3CPh2Si ethers, or isopropylidene acetals were unchanged. Interestingly, a selective alkoxy-PMB cleavage was observed in the presence of a PMB phenoxy ether.
- Rival, Nicolas,Albornoz Grados, Arantxa,Schiavo, Lucie,Colobert, Fran?oise,Hanquet, Gilles
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p. 6823 - 6826
(2015/11/27)
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- Compositions and methods for treating viral infections
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The present invention provides compositions methods for treating susceptible viral infections, especially hepatitis C viral (HCV) infections as well as co infections of HCV with other viruses such as HBV and/or HIV. In one embodiment, the present inventio
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Page/Page column 38
(2015/10/28)
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- Selective catalytic oxidation of alcohols, aldehydes, alkanes and alkenes employing manganese catalysts and hydrogen peroxide
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The manganese-containing catalytic system [MnIV,IV 2O3(tmtacn)2]2+ (1)/carboxylic acid (where tmtacn=N,N′,N′′-trimethyl-1,4,7-triazacyclononane), initially identified for the cis-dihydroxylation and epoxidation of alkenes, is applied for a wide range of oxidative transformations, including oxidation of alkanes, alcohols and aldehydes employing H2O2 as oxidant. The substrate classes examined include primary and secondary aliphatic and aromatic alcohols, aldehydes, and alkenes. The emphasis is not primarily on identifying optimum conditions for each individual substrate, but understanding the various factors that affect the reactivity of the Mn-tmtacn catalytic system and to explore which functional groups are oxidised preferentially. This catalytic system, of which the reactivity can be tuned by variation of the carboxylato ligands of the in situ formed [MnIII,III 2(O)(RCO2)2(tmtacn)2]2+ dimers, employs H2O2 in a highly atom efficient manner. In addition, several substrates containing more than one oxidation sensitive group could be oxidised selectively, in certain cases even in the absence of protecting groups. Copyright
- Saisaha, Pattama,Buettner, Lea,Van Der Meer, Margarethe,Hage, Ronald,Feringa, Ben L.,Browne, Wesley R.,De Boer, Johannes W.
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p. 2591 - 2603
(2013/10/21)
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- Rate-acceleration in gold-nanocluster-catalyzed aerobic oxidative esterification using 1,2- and 1,3-diols and their derivatives
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Aerobic oxidation of aldehydes to 1,2- and 1,3-diol monoesters was catalyzed by polymer-incarcerated gold nanoclusters under ambient conditions. The esterification proceeded much faster with 1,2- and 1,3-diols and their derivatives rather than with methanol. Magnum PI: Gold-nanocluster catalysts, PI-Au, that were immobilized on polystyrene-based polymers with cross-linking moieties, were used to catalyze the syntheses of 1,2 and 1,3-diol monoesters and their derivatives from aldehydes. The effect of neighboring-group participation in the esterification reaction is also described. Copyright
- Yasukawa, Tomohiro,Miyamura, Hiroyuki,Kobayashi, Shu
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experimental part
p. 621 - 627
(2011/10/12)
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- Organocatalytic chemoselective monoacylation of 1,n-linear diols
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Matters of length: Exclusive or predominant monoacylation of 1,n-linear diols took place in the presence of 1 when the chain length of linear diols was equal to or shorter than five carbon atoms. The chemoselectivity of acylation between 1,5-pentanediol (n=5) and 1,6-hexanediol (n=6) was 5.2, and that between 1,5-pentanediol and its monoacylate was 113. Copyright
- Yoshida, Keisuke,Furuta, Takumi,Kawabata, Takeo
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supporting information; experimental part
p. 4888 - 4892
(2011/06/22)
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- Nucleotide and oligonucleotide prodrugs
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The present invention discloses compounds of formula (I): which exhibit antiviral properties. The present invention further relates to pharmaceutical compositions comprising the aforementioned compounds for administration to a subject in need of anti-HBV
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Page/Page column 23
(2008/06/13)
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- Mild preparation of alkenes from phenyl sulfides: One-pot elimination of phenylthio group via sulfilimine at ambient temperature
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(Chemical Equation Presented) Various alkenes were prepared from phenyl sulfides in a one-pot manner at room temperature by converting them to the corresponding S-aminosulfonium salts with O-mesitylenesulfonylhydroxylamine, followed by treatment with pota
- Matsuo, Jun-Ichi,Kozai, Takaaki,Ishibashi, Hiroyuki
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p. 6095 - 6098
(2007/10/03)
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- Acyclic nucleoside analogues as inhibitors of Plasmodium falciparum dUTPase
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We report the discovery of novel uracil-based acyclic compounds as inhibitors of deoxyuridine 5′-triphosphate nucleotidohydrolase (dUTPase), an enzyme involved in nucleotide metabolism that has been identified as a promising target for the development of
- Nguyen, Corinne,Ruda, Gian Filippo,Schipani, Alessandro,Kasinathan, Ganasan,Leal, Isabel,Musso-Buendia, Alexander,Kaiser, Marcel,Brun, Reto,Ruiz-Pérez, Luis M.,Sahlberg, Britt-Louise,Johansson, Nils Gunnar,González-Pacanowska, Dolores,Gilbert, Ian H.
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p. 4183 - 4195
(2007/10/03)
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- DUTPASE INHIBITORS
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Deoxyuridine derivatives of the formula (I) where R1 is H or various substituents; D is -NHCO-, -CONH-, -0-, -C(=O)-, -CH=CH, -CΞC-, -NR5-; R4 is hydrogen or various substituents; R5 is H, C1-C4 alkyl, C1-C4 alkanoyl; E is Si or C; R6, R7 and R8 are independently selected from C1-C8 alkyl, C2-C8 alkenyl, C2-C8 alkynyl or a stable monocyclic, bicyclic or tricyclic ring system; G is -O-, -S-, -CHR10-, -C(=O)-; J is -CH2-, or when G is CHR10 may also be -O- or -NH-; R10 is H, F, -CH3, -CH2NH2, -CH2OH; -OH R11 is H, F, -CH3, -CH2 NH2, -CH2OH, CH(OH)CH3, CH(NH3)CH3; or R10 and R11 together define an olefinic bond, or together form a -CH2-group, thereby defining a cis or trans cyclopropyl group; have utility in the prophylaxis or treatment of protozoal diseases such as malaria.
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Page/Page column 32
(2008/06/13)
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- gem-difluorovinyl derivatives as insecticides and acaricides
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The insecticidal lead 1,1-difluorododec-1-ene was optimised. This compound has attractive insecticidal activity against tobacco budworm (Heliothis virescens), banded cucumber beetle (Diabrotica balteata), pea aphid (Aphis cracciovora), brown planthopper (
- Pitterna, Thomas,Boeger, Manfred,Maienfisch, Peter
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p. 108 - 116
(2007/10/03)
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- Bismuth(III) chloride catalyzed efficient and selective cleavage of trityl ethers
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A highly selective and efficient protocol has been developed for detritylation using 5 mol% BiCl3 in acetonitrile. The cleavage proceeds at room temperature in high yields and the conditions are mild enough to tolerate a variety of acid-base sensitive functional groups.
- Sabitha, Gowravaram,Reddy, E. Venkata,Swapna,Reddy, N. Mallikarjun,Yadav
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p. 1276 - 1278
(2007/10/03)
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- A simple and useful synthetic protocol for selective deprotection of tert-butyldimethylsilyl (TBS) ethers
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A wide variety of tert-butyldimethylsilyl ethers 1 can be easily cleaved to the corresponding parent hydroxyl compound 2 in the presence of 5 mol % of acetonyltriphenylphosphonium bromide (ATPB) at room temperature. In addition, tert-butyldiphenylsilyl ethers can also be cleaved by using 20 mol % of the same catalyst. Alkyl tert-butyldimethylsilyl ethers can be deprotected to the hydroxyl compounds chemoselectively in the presence of aryl tert- butyldimethylsilyl ethers. Some of the major advantages are mild reaction conditions, no aqueous workup, high efficiency and chemoselectivity and compatibility with other protecting groups; no brominations occur in the aromatic ring under these experimental conditions. Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004.
- Khan, Abu T.,Ghosh, Subrata,Choudhury, Lokman H.
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p. 2198 - 2204
(2007/10/03)
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- A highly efficient and useful synthetic protocol for the cleavage of tert-butyldimethylsilyl (TBS) ethers using a catalytic amount of acetyl chloride in dry methanol
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A wide variety of tert-butyldimethylsilyl (TBS) ethers as well as tert-butyldiphenylsilyl (TBDPS) ethers 1 can be easily deprotected to the corresponding parent hydroxyl compounds 2 by employing catalytic amounts of acetyl chloride in dry MeOH at 0°C to room temperature in good yields. Some of the major advantages are mild conditions, high efficiency, high selectivity, high yields, easy operation, and also compatibility with other protecting groups. Furthermore, no acetylation nor chlorination takes place under the experimental conditions.
- Khan, Abu T.,Mondal, Ejabul
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p. 694 - 698
(2007/10/03)
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- Facile and Chemo-selective Cleavages of Allyl Ethers Utilizing Tetrabutylammonium Sulfate Radical Species
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Allyl ethers containing various functional groups reacted with tetrabutylammonium peroxydisulfate in acetonitrile under mild conditions to afford the corresponding cleaved alcohols in excellent yields.
- Yang, Seung Gak,Park, Min Young,Kim, Yong Hae
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p. 492 - 494
(2007/10/03)
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- Tris(2,4,6-trimethoxyphenyl)phosphine (TTMPP): A novel catalyst for selective deacetylation
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Chemo-and stereoselective deacetylation was achieved by the use of a catalytic amount of tris(2,4,6-trimethoxyphenyl)phosphine (TTMPP).
- Yoshimoto, Kazuya,Kawabata, Hirotoshi,Nakamichi, Natsuki,Hayashi, Masahiko
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p. 934 - 935
(2007/10/03)
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- Tetrabutylammonium tribromide (TBATB) - MeOH: An efficient chemoselective reagent for the cleavage of tert-butyldimethylsilyl (TBDMS) ethers
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(equation presented) R = H, alkyl or aryl P = TBDMS, TBDPS, THP, DMT TBDMS THP and DMT ethers are efficiently deprotected with tetrabutylammonium tribromide in methanol. The apparent order of stability of different protecting group is phenolic TBDMS > 1° OTBDPS > 2° OTBDMS > 2° OTHP > 1° OTHP > 1° OTBDMS > 1° ODMT. TBDMS ether has been cleaved selectively in the presence of isopropylidine, Bn, Ac, Bz, THP, and TBDPS groups. This method is high yielding, fast, clean, safe, cost-effective, and therefore most suitable for practical organic synthesis.
- Gopinath, Rangam,Patel, Bhisma K.
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p. 4177 - 4180
(2007/10/03)
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- A mild and selective cleavage of tert-butyldimethylsilyl ethers by indium(III) chloride
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Alkyl tert-butyldimethylsilyl ethers are selectively deprotected to the corresponding alcohols in high yields for the first time by indium(III) chloride in refiuxing aqueous acetonitrile. Several functional groups like OBn, Boc, CBz, OBz, O-allyl, OTBDPS, OAc, OMe, ethers, esters and olefins present in the substrate are unaffected.
- Yadav,Subba Reddy,Madan
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p. 853 - 854
(2007/10/03)
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- Chemo- and stereoselective monobenzoylation of 1,2-diols catalyzed by organotin compounds
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A new facile method for monoacylation of diols has been developed. A variety of cyclic and acyclic diols, in particular 1,2-diols, were selectively monobenzoylated in good yields by the reaction with benzoyl chloride in the presence of a catalytic amount of dimethyltin dichloride and inorganic bases such as potassium carbonate. Furthermore, the method was successfully applied to a kinetic resolution of racemic 1-phenyl-1,2- ethanediol using a chiral organotin catalyst. The ee was dependent on the kind of base, water as an additive, and the reaction temperature.
- Iwasaki, Fumiaki,Maki, Toshihide,Onomura, Osamu,Nakashima, Waka,Matsumura, Yoshihiro
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p. 996 - 1002
(2007/10/03)
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- A new convenient method for selective monobenzoylation of diols
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A new facile method for monoacylation of diols has been developed. A variety of cyclic and acyclic diols, in particular 1,2-diols, was selectively monobenzoylated in good yields by their reaction with benzoyl chloride in the presence of a catalytic amount of dimethyltin dichloride and inorganic bases.
- Maki, Toshihide,Iwasaki, Fumiaki,Matsumura, Yoshihiro
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p. 5601 - 5604
(2007/10/03)
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- Synthesis of the Sda determinant and two analogous tetrasaccharides.
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To contribute to the possibility of studying in greater detail the biological significance of Sda-containing glycans as occur in Tamm-Horsfall glycoprotein, the following three spacer-linked tetrasaccharides have been synthesized: the Sda determinant alpha-Neu p5Ac-(2-->3)-[beta- D-GalpNAc-(1-->4)]-beta-D-Galp-(1-->4)-beta-D-GlcpNAc-(1-->O)(CH2)5NH 2 (1), the Gal-analogue alpha-Neup5Ac-(2-->3)-[beta-D-Galp-(1-->4)]-beta-D-Galp-(1-->4) -beta-D-GlcpNAc-(1-->O)(CH2)5NH2 (2), and the GlcNAc-analogue alpha-Neup5Ac-(2-->3)-[beta-D-GlcpNAc-(1-->4)]- beta-D-Galp-(1-->4)-beta-D-GlcpNAc-(1-->O)(CH2)5NH2 (3). The general trisaccharide acceptor 5-azidopentyl (methyl 5-acetamido-4,7,8,9-tetra-O-acetyl-3,5-dideoxy- D-glycero-alpha-D-galactonon-2-ulopyranosylonate)-(2-->3)-(2 ,6-di-O-benzyl- beta-D-galactopyranosyl)-(1-->4)-3,6-di-O- benzyl-2-deoxy-2-phthalimido-beta-D-glucopyranoside was prepared, using methyl (phenyl 5- acetamido-4,7,8,9-tetra-O-acetyl-3,5-dideoxy-2-thio-D-glycero-D-galacto- non- 2-ulopyranosid)- onate as the sialyl donor. For the syntheses of 1, 2, and 3 the glycosyl donors 3,4,6-tri-O- acetyl-2-deoxy-2-phthalimido-alpha-D-galactopyranosyl bromide, 2,3,4,6-tetra-O-acetyl-alpha-D- galactopyranosyl bromide, and 3,4,6-tri-O-acetyl-2-deoxy-2-phthalimido -beta-D-glucopyranosyl trichloroacetimidate, respectively, proved to be the most suitable.
- van Seeventer,Kamerling,Vliegenthart
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p. 181 - 195
(2007/10/03)
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- Termination of radical-polar crossover reactions by intramolecular nucleophiles
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Radical-polar crossover reactions featuring intramolecular nucleophilic termination are reported.
- Murphy, John A.,Rasheed, Faiza,Roome, Stephen J.,Lewis, Norman
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p. 737 - 738
(2007/10/03)
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- Asymmetric Hydrosilylation of 1-Alkenes Catalyzed by Palladium-MOP
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Asymmetric hydrosilylation of simple terminal alkenes (RCH=CH2) with trichlorosilane at 40 deg C in the presence of 1*10-3 or 1*10-4 molar amounts of palladium catalyst prepared in situ from 3-C3H5)>2 and (S)-2-diphenylphosphino-2'-methoxy-1,1'-binaphthyl ((S)-MeO-MOP) proceeded with unusual regioselectivity and with high enantioselectivity to give high yields of 2-(trichlorosilyl)alkanes together with a minor amount of 1-(trichlorosilyl)alkanes.Optically active alcohols, RCH(OH)CH3, were obtained by oxidation of the carbon-silicon bond.Regioselectivities for forming 2-silylalkanes over 1-silylalkanes and enantiomeric purities of alcohols are as follows: R=n-C4H9: 89/11, 94percent ee (R).R=n-C6H13: 93/7, 95percent ee (R).R=n-C10H21: 94/6, 95percentee (R).R=PhCH2CH2: 81/19, 97percentee (S).R=PhCH2CH2CH2: 80/20, 92percent ee (R).R=cyclo-C6H11: 66/34, 96percent ee (R).A similar hydrosilylation of 1-alkenes, 4-pentenyl benzoate and 1,5-heptadiene gave corresponding 2-alkanols of 90percent ee and 87percent ee, respectively, the ester carbonyl and the internal double bond remaining intact.
- Uozumi, Yasuhiro,Kitayama, Kenji,Hayashi, Tamio,Yanagi, Kazunori,Fukuyo, Emiko
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p. 713 - 722
(2007/10/02)
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- Halogenated olefins, processes for their preparation and their use as pesticides
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This are described new halogenated olefines of general formula I STR1 in which X1, X2, X3, n and A have the meanings given in the description as well as processes for their preparation. The compounds can be used as pesticides especially against insects and acarids.
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- Oxidation of ω-(Benzoyloxy)alkanols with an Oxoaminium Salt
-
Oxoaminium chloride (2), the oxidized derivative of 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO, 1), was found to display a novel selectivity in the oxidation of ester group containing alcohols.The oxidation of (2 to 6)-(benzoyloxy)alkanols and related alcohols were carried out at room temperature with 1.0 equiv. of the oxoaminium chloride in dichloromethane (method A) or with 0.1 equiv. of TEMPO, 1.5 equiv. of cupric chloride, and 1.5 equiv. of cupric hydroxide (method B).Whereas the oxoaminium chloride did not significantly oxidize 2-(benzoyloxy)ethanol and 3-(benzoyloxy)propanol, it did oxidize 4-(benzoyloxy)butanol, 5-(benzoyloxy)pentanol and 6-(benzoxyloxy)hexanol to the corresponding (benzoyloxy)alkanals.The origin of this selectivity was investigated, and NMR and other studies suggest that the selectivity might be attributed to the inductive effect of the ester group.
- Yamaguchi, Masao,Takata, Toshikazu,Takeshi, Endo
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p. 1490 - 1492
(2007/10/02)
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