- 2D NMR Nutation Analysis of Non-Thermal Polarization of Coupled Multi-Spin Systems
-
A new, convenient method of analyzing the spin polarization of a non-equilibrium system of N coupled nuclei is described and applied to photo-reactions exhibiting chemically induced dynamic nuclear polarization (CIDNP). It is based on the Fourier analysis of the variation of NMR line intensities as a function of the radio frequency excitation pulse length. A relationship between the spectral components at various harmonic order and the alignment in the spin multiplet is established. In application to the Norrish type I photolysis of cyclodecanone we demonstrate that at low magnetic field the rate determining step in the reaction kinetics depends on the mutual orientation of at least four pairs of non-equivalent spins.
- Ivanov,Miesel,Vieth,Yurkovskaya,Sagdeev
-
-
Read Online
- Convenient synthesis of novel macrocyclic urethanes: Alkoxycarbonylation of amines and ring-closing metathesis strategy
-
Alkoxycarbonylation of amines followed by ring-closing metathesis of the resulting dienes with Grubbs catalyst (25-50 mol%) provided convenient access to 14-16 membered macrocyclic urethanes in very good yields.
- Ghosh, Arun K.,Hussain, Khaja Azhar
-
-
Read Online
- The Effects of Material Properties on the Activity of Sol-Gel Entrapped Perruthenate under Supercritical Conditions
-
Silica gels organically modified and doped with the ruthenium species tetra-n-propylammonium perruthenate (TPAP) are leach-proof, selective catalysts for the aerobic oxidation of alcohols to carbonyl compounds with dioxygen at low pressure in compressed carbon dioxide. The catalytic sol-gels are recyclable and the correlation between the reactivity of the materials and their surface polarity and textural properties suggests valuable information on the chemical behaviour of sol-gel entrapped silica catalysts in oxidation catalysis which is of relevant interest considering the importance of heterogeneous oxidative dehydrogenation of alcohols in fine chemistry. An explanation of the structure-activity relationship is proposed to provide guidelines for the further development of efficient solid oxidation catalysts for conversions in supercritical carbon dioxide.
- Ciriminna, Rosaria,Campestrini, Sandro,Pagliaro, Mario
-
-
Read Online
- Highly efficient liquid-phase oxidation of primary alcohols to aldehydes with oxygen catalysed by Ru-Co oxide
-
RuIV-CoIII (1:1.5) binary oxide, prepared by co-precipitation, is a highly efficient solid catalyst for the oxidation of primary alcohols to aldehydes with O2 (76-95% selectivity at 54-100% conversion) in a liquid phase under atmospheric pressure.
- Musawir, Mehdi,Davey, Paul N.,Kelly, Gordon,Kozhevnikov, Ivan V.
-
-
Read Online
- Straightforward Synthesis of Fluorinated Enals via Photocatalytic α-Perfluoroalkenylation of Aldehydes
-
(Per)fluorinated substances represent an important compound class with regard to drug design and material chemistry. We found a mild, operationally simple, and inexpensive photocatalytic perfluoroalkenylation reaction giving tetrasubstituted, highly electron-deficient enals straight from aldehydes. This one-step reaction tolerates various functional groups and can be applied to a wide range of substrates giving the products in yields of 52-84%.
- Wulkesch, Christian,Czekelius, Constantin
-
p. 7425 - 7438
(2021/06/21)
-
- Racemic or enantioselective osmium-catalyzed dihydroxylation of olefins under near-neutral conditions
-
K3Fe(CN)6 and NaIO4 serve as catalytic co-oxidants for osmium-catalyzed dihydroxylations that are performed under near-neutral conditions with K2S2O8 as the stoichiometric oxidant and Na2HPO4 as the base. By using either quinuclidine or hydroquinidine 1,4-phthalazinediyl ether [(DHQD)2Phal], good yields of racemic or enantioenriched diols are obtained. This simple, biphasic procedure offers advantages over other neutral dihydroxylation protocols that use N-methylmorpholine oxide as the stoichiometric oxidant, by suppressing the secondary catalytic cycle that leads to reduced enantioselectivities. The utility of the procedure, which is nicely suited for base-labile starting materials or products, is demonstrated by performing the dihydroxylation in the presence of an aliphatic aldehyde moiety.
- Blumberg, Shawn,Martin, Stephen F.
-
-
- One-pot, two-step synthesis of unnatural α-amino acids involving the exhaustive aerobic oxidation of 1,2-diols
-
Herein, we report the nor-AZADO-catalyzed exhaustive aerobic oxidations of 1,2-diols to α-keto acids. Combining oxidation with transamination using dl-2-phenylglycine led to the synthesis of free α-amino acids (AAs) in one pot. This method enables the rapid and flexible preparation of a variety of valuable unnatural AAs, such as fluorescent AAs, photoactivatable AAs, and other functional AAs for bioorthogonal reactions.
- Inada, Haruki,Furukawa, Keisuke,Shibuya, Masatoshi,Yamamoto, Yoshihiko
-
supporting information
p. 15105 - 15108
(2019/12/26)
-
- Direct Synthesis of Free α-Amino Acids by Telescoping Three-Step Process from 1,2-Diols
-
A practical telescoping three-step process for the syntheses of α-amino acids from the corresponding 1,2-diols has been developed. This process enables the direct synthesis of free α-amino acids without any protection/deprotection step. This method was also effective for the preparation of a 15N-labeled α-amino acid. 1,2-Diols bearing α,β-unsaturated ester moieties afforded bicyclic α-amino acids through intramolecular [3 + 2] cycloadditions. A preliminary study suggests that the resultant α-amino acids are resolvable by aminoacylases with almost complete selectivity.
- Inada, Haruki,Shibuya, Masatoshi,Yamamoto, Yoshihiko
-
supporting information
p. 709 - 713
(2019/01/25)
-
- Copper(i)-catalysed stereoselective debromoborylation of aliphatic 1,1-dibromo-1-alkenes with bis(pinacolato)diboron
-
A stereoselective debromoborylation of aliphatic 1,1-dibromo-1-alkenes to prepare (Z)-1-bromo-1-alkenylboronate esters using copper(i) catalysts was developed. The debromoborylation of various aliphatic 1,1-dibromo-1-alkenes in the presence of a copper(i) catalyst and bis(pinacolato)diboron proceeded smoothly to produce (Z)-1-bromo-1-alkenylboronate esters in good yields with only Z geometry.
- Pang, Yadong,Kojima, Ryoto,Ito, Hajime
-
supporting information
p. 6187 - 6190
(2018/09/10)
-
- Resorcylic acid lactone biosynthesis relies on a stereotolerant macrocyclizing thioesterase
-
Zearalenone and radicicol are highly related resorcylic acid lactones with the rare property of having opposite stereochemical configurations of the secondary alcohol involved in lactone formation. The ability of the thioesterases from the zearalenone and radicicol biosynthetic pathways to macrocyclize both d and l configured synthetic substrate analogs was biochemically characterized and showed that both enzymes were highly stereotolerant, macrocyclizing both substrates with similar kinetic parameters. This observed stereotolerance is consistent with a proposed evolution of both natural products from a common ancestral resorcylic acid lactone.
- Heberlig, Graham W.,Wirz, Monica,Wang, Meng,Boddy, Christopher N.
-
supporting information
p. 5858 - 5861
(2015/02/19)
-
- A relay ring-opening/double ring-closing metathesis strategy for the bicyclic macrolide-butenolide core structures
-
A concise strategy has been developed for the synthesis of the bicyclic macrolide-butenolide core structures of various natural products with the macrolide ring size ranging from 12- to 16-membered. The bicyclic structure was easily assembled using the relay ring-opening/double ring-closing metathesis strategy. An efficient synthesis of (±)-desmethyl manshurolide has been achieved as an application of this strategy. This journal is
- Halle, Mahesh B.,Fernandes, Rodney A.
-
p. 63342 - 63348
(2015/02/19)
-
- METHOD FOR OXIDIZING ALCOHOLS
-
A method for oxidizing an alcohol, wherein oxidation is performed in the presence of a compound represented by the following formula (I) and a bulk oxidant, which enables efficient oxidation of secondary alcohols as well as primary alcohols, and can attain high reaction efficiency even when air is used as a bulk oxidant.
- -
-
Paragraph 0129; 0130
(2013/06/05)
-
- Entry to β-alkoxyacrylates via gold-catalyzed intermolecular coupling of alkynoates and allylic ethers
-
The first gold-catalyzed intermolecular coupling of alkynoates and allylic ethers invoking alkoxy addition and [3,3]-sigmatropic rearrangement as the key mechanism has been developed. Remarkably, the reaction showed complete chemoselectivity toward the pathway initiated by the alkoxy addition to alkynes. This unprecedented reactivity led to a new access to diversely substituted β-alkoxyacrylates in a highly efficient manner.
- Park, Sae Rom,Kim, Cheoljae,Kim, Dong-Gil,Thrimurtulu, Neetipalli,Yeom, Hyun-Suk,Jun, Jungho,Shin, Seunghoon,Rhee, Young Ho
-
supporting information
p. 1166 - 1169
(2013/05/09)
-
- Oxidation of alcohols to carbonyl compounds with diisopropyl azodicarboxylate catalyzed by nitroxyl radicals
-
A nitroxyl-radical-catalyzed oxidation of alcohols using diisopropyl azodicarboxylate (DIAD) as the terminal oxidantis reported. A variety of primary and secondary alcohols including aliphatic, benzylic, and allylic alcohols are efficiently oxidized to their corresponding aldehydes and ketones without overoxidation to carboxylic acid. 1,2-Diols are oxidized to hydroxyl ketones or diketones depending on the amount of DIAD used.
- Hayashi, Masaki,Shibuya, Masatoshi,Iwabuchi, Yoshiharu
-
experimental part
p. 3005 - 3009
(2012/05/04)
-
- Development of new recyclable reagents and catalytic systems based on hypervalent iodine compounds
-
Recent advances in the development of polymer-supported iodine(V) oxidants, recyclable monomeric hypervalent iodine(III) reagents and catalytic systems based on hypervalent iodine compounds are discussed. These efficient and environmentally friendly reagents and catalysts are particularly useful for oxidative transformations of alcohols to carbonyl compounds and for oxidations at the benzylic position.
- Yusubov, Mekhman S.,Zhdankin, Viktor V.
-
experimental part
p. 185 - 191
(2011/03/19)
-
- 2-iodoxybenzenesulfonic acid as an extremely active catalyst for the selective oxidation of alcohols to aldehydes, ketones, carboxylic acids, and enones with oxone
-
Electron-donating group-substituted 2-iodoxybenzoic acids (IBXs) such as5-Me-IBX (1g), 5-MeO-IBX (1h), and 4,5-Me2-IBX were superior to IBX 1a as catalysts for the oxidation of alcohols with Oxone (a trad emark of DuPont) under nonaqueous conditions, although Oxone was almost insoluble in most organic solvents. The catalytic oxidation proceeded more rapidly and cleanly in nitromethane. Furthermore, 2-iodoxybenzenesulfonic acid (IBS, 6a) was much more active than modified IBXs. Thus, we established a highly efficient and selective method for the oxidation of primary and secondary alcohols to carbonyl compounds such as aldehydes, carboxylic acids, and ketones with Oxone in nonaqueous nitromethane, acetonitrile, or ethyl acetate in the presence of 0.05-5molpercentof 6a, which was generated in situ from 2-iodobenzenesulfonic acid (7a) or its sodium salt. Cycloalkanones could be further oxidized to α,β- cycloalkenones or lactones by controlling the amounts of Oxone under the same conditions as above. When Oxone was used under nonaqueous conditions, Oxone wastes could be removed by simple filtration. Based on theoretical calculations, we considered that the relatively ionic character of the intramolecular hypervalent iodine-OSO2 bond of IBS might lower the twisting barrier of the alkoxyperiodinane intermediate 16.
- Uyanik, Muhammet,Akakura, Matsujiro,Ishihara, Kazuaki
-
supporting information; experimental part
p. 251 - 262
(2009/06/28)
-
- Synthetic ansamycins prepared by a ring-expanding Claisen rearrangement. Synthesis and biological evaluation of ring and conformational analogues of the Hsp90 molecular chaperone inhibitor geldanamycin
-
A series of ansa-quinones has been prepared by chemical synthesis, and evaluated by biological techniques. Thus, 19-membered ansa-lactams, simplified analogues of the naturally occurring Hsp90 molecular chaperone inhibitor geldanamycin, were obtained by concise routes, the key steps being the combination of a ring-closing metathesis to give a 17-membered ring followed by Claisen rearrangement to effect ring expansion. The methodology was also used to prepare an "unnatural" 18-membered ring analogue. In ATPase enzyme assays, the synthetic ansa-quinones were weak inhibitors of Hsp90. The Royal Society of Chemistry 2007.
- McErlean, Christopher S. P.,Proisy, Nicolas,Davis, Christopher J.,Boland, Nicola A.,Sharp, Swee Y.,Boxall, Kathy,Slawin, Alexandra M. Z.,Workman, Paul,Moody, Christopher J.
-
p. 531 - 546
(2008/03/27)
-
- Facile preparation and reactivity of polymer-supported N-(2-lodyl-phenyl)- acylamide, an Efficient Oxidizing System
-
(Chemical Equation Presented) A simple three-step preparation of polymer-supported N-(2-iodyl-phenyl)-acylamide (NIPA resin) starting from 2-iodoaniline is described. The resin was obtained with good loading levels (0.7-0.8 mmol g-1) and has been successfully used for efficient oxidation of a diverse collection of alcohols. Thus, treating alcohols with 1.0 equiv of the resin in 1,2-dichloroethane under reflux for 30-60 min allowed rapid and in most cases complete conversion to the corresponding carbonyl compound.
- Ladziata, Uladzimir,Willging, Jeff,Zhdankin, Viktor V.
-
p. 167 - 170
(2007/10/03)
-
- Liquid-phase oxidation of alcohols by oxygen and nitrous oxide catalysed by Ru-Co oxide
-
Chemoselective catalysts in bulk or supported on γ-Al 2O3 binary oxides RuIV-CoIII (Ru/Co = 1:1-1:2), prepared by co-precipitation, were used for liquid-phase oxidation of saturated and unsaturated primary and secondary alcohols to aldehydes and ketones with O2 or N2O. The catalysts can be separated by filtration and reused. No leaching of Ru or Co in solution was observed. The oxidation is enhanced by the presence of hydration water in the Ru-Co catalyst, which indicates the participation of active RuIV hydroxo species in the reaction. From XRD and TGA, the Ru-Co oxide can be approximated as a hydrous binary oxide comprising the amorphous RuO2 and heterogenite-3R cobaltic acid CoO(OH). The alcohol oxidation appears to occur by a nonradical mechanism, which may be viewed as an oxidative dehydrogenation of alcohols to form an aldehyde or ketone. H2-TPR shows that CoIII practically does not affect the oxidising ability of RuO2. This suggests that the cobalt is likely to enhance catalyst reoxidation by O 2 rather than to play a significant role in the alcohol dehydrogenation. The alcohol oxidation by N2O exhibits a close similarity to the oxidation by O2 but is much less efficient. Much more active catalysts are required to make the oxidation with N2O synthetically useful.
- Stuchinskaya, Tatiana L.,Musawir, Mehdi,Kozhevnikova, Elena F.,Kozhevnikov, Ivan V.
-
-
- Site-selective abstraction in the reaction of 5-20 eV O+ with a self-assembled monolayer
-
Site-specific reaction of hyperthermal O+ with a self-assembled monolayer is described. Isotopic labeling experiments reveal the percentage of abstraction products formed from hydrogen atoms bound originally to the top three carbon atoms in the chain. Copyright
- Qin, Xiangdong,Tzvetkov, Tochko,Liu, Xin,Lee, Dong-Chan,Yu, Luping,Jacobs, Dennis C.
-
p. 13232 - 13233
(2007/10/05)
-
- Precursors for fragrant ketones and fragrant aldehydes
-
The present invention refers to fragrance precursors of formula I for a fragrant ketone of formula II and one or more fragrant aldehydes or ketones of formula III and IV, These fragrance precursors are useful in perfumery, especially in the fine and functional perfumery.
- -
-
-
- Novel cyclourethane-derived HIV protease inhibitors: A ring-closing olefin metathesis based strategy
-
A series of novel macrocyclic urethanes incorporating a (R)-hydroxyethylamine isostere was designed and synthesized. Ring size and substituent efffects have been investigated. Cyclourethanes containing 14- to 16-membered rings exhibited low nanomolar inhibitory potencies against HIV-1 protease.
- Ghosh, Arun K.,Swanson, Lisa M.,Liu, Chunfeng,Hussain, Khaja Azhar,Cho, Hanna,Walters,Holland, Louis,Buthod, Jim
-
p. 1993 - 1996
(2007/10/03)
-
- Chemoenzymatic synthesis of (+)-aspicilin from chlorobenzene
-
(matrix presented) The enantiomerically pure cis-1,2-dihydrocatechol 2, which is obtained by microbial oxidation of chlorobenzene, has been converted, via intermediate 3, into the natural product (+)-aspicilin (1).
- Banwell, Martin G.,McRae, Kenneth J.
-
p. 3583 - 3586
(2007/10/03)
-
- Metalloporphyrin-catalyzed regioselective rearrangement of monoalkyl-substituted epoxides into aldehydes
-
Iron(III) tetraphenylporphyrin, Fe(tpp)OTf, is an efficient catalyst for the regioselective rearrangement of simple monoalkyl-substituted epoxides into the corresponding aldehydes.
- Suda, Kohji,Baba, Kenji,Nakajima, Shin-ichiro,Takanami, Toshikatsu
-
p. 7243 - 7246
(2007/10/03)
-
- Dehomologation of Aldehydes via Oxidative Cleavage of Silyl Enol Ethers with Aqueous Hydrogen Peroxide Catalyzed by Cetylpyridinium Peroxotungstophosphate under Two-Phase Conditions
-
Dehomologation of aldehydes has been first successfully achieved via oxidative cleavage of silyl enol ethers, derived from aldehydes and trimethylchlorosilane, using aqueous hydrogen peroxide in the presence of a catalytic amount of peroxotungstophophate (PCWP) under phase-transfer conditions. For instance, the oxidation of 1-[(trimethylsilyl)oxy]-1-octene resulting from octanal and Me3SiCl with 35% H2O2 catalyzed by PCWP in dichloromethane at room temperature afforded the one-carbon shorter aldehyde, heptanal, in 79% yield. A variety of silyl enol ethers were also converted into one-carbon shorter aldehydes in good yields. The oxidation under homogeneous conditions using tert-butyl alcohol gave hydrolysis products such as 2-oxooctanol and octanal. It is of interest that [1-(trimethylsilyl)oxy]-1,10-undecadiene involving an enol moiety and a terminal double bond afforded exclusively 9-decenal, in which the enol moiety was selectively oxidized. A plausible reaction path for the oxidative cleavage of silyl enol ethers by the present system has been suggested from the oxidation results of α-[(trimethylsilyl)oxy]styrene.
- Sakaguchi, Satoshi,Yamamoto, Yumiko,Sugimoto, Takuma,Yamamoto, Hiroyo,Ishii, Yasutaka
-
p. 5954 - 5957
(2007/10/03)
-
- α hydroxylation of carboxylic acids with molecular oxygen catalyzed by the α oxidase of peas (Pisum sativum): A novel biocatalytic synthesis of enantiomerically pure (R)-2-hydroxy acids
-
The substrate selectivities of the α oxidation of saturated, unsaturated, and heteroatom-containing (oxygen, sulfur) carboxylic acids 1 by the enzyme extract of peas (Pisum sativum) indicate that this biotransformation proceeds highly enantioselectively. For the first time, the synthesis of optically pure 2-hydroxy acids 2 has been achieved on the semipreparative scale (1 mmol) by α hydroxylation of long-chain carboxylic acids with molecular oxygen, catalyzed by the α oxidase of peas. For derivatives with sulfur atom in the chain, no sulfoxidation is observed. The functionalities (carbon double and triple bonds, oxygen, and sulfur atoms) must be at least three carbon atoms away from the carboxylic acid group to achieve efficient asymmetric hydroxylation. The absolute configuration of the 2-hydroxy acids 2 was assigned by comparison of the gaschromatographic data with that of authentic reference compounds and by application of the exciton- coupled-circular-dichroism (ECCD) method. This unprecedented asymmetric biocatalytic methodology should be valuable for the preparation of enantiomerically pure (R)-2-hydroxy acids.
- Adam, Waldemar,Boland, Wilhelm,Hartmann-Schreier, Jenny,Humpf, Hans-Ulrich,Lazarus, Michael,Saffert, Alexander,Saha-M?ller, Chantu R.,Schreier, Peter
-
p. 11044 - 11048
(2007/10/03)
-
- Selective Isomerization of 1,2-Epoxyalkanes to Aldehydes with Lithium Dialkylamides
-
Reaction of a variety of 1,2-epoxyalkanes with 2.5 equiv. of bulky metal amide - lithium 2,2,6,6-tetramethylpiperidide - affords the corresponding aldehydes exclusively in high yields; this is the first example of base-promoted isomerization of monosubstituted epoxides to aldehydes.
- Yanagisawa, Akira,Yasue, Katsutaka,Yamamoto, Hisashi
-
p. 2103 - 2104
(2007/10/02)
-
- Chromium(VI) or Ruthenium(II) Complex Catalysis in Oxidation of Alcohols to Aldehydes and Ketones by Means of Bis(trimethylsilyl) Peroxide
-
Bis(trimethylsilyl) peroxide (BTSP) serves as an effective oxidant of alcohols in the presence of chromium(VI) or ruthenium(II) complexes as catalysts in dichloromethane.Selective oxidation of primary alcohols in preference to secondary ones using RuCl2(PPh3)3 as a catalyst is also described.
- Kanemoto, Shigekazu,Matsubara, Seijiro,Takai, Kazuhiko,Oshimara, Koichiro,Utimoto, Kiitiro,Nozaki, Hitosi
-
p. 3607 - 3612
(2007/10/02)
-