- Carbonylative Polymerization of Epoxides Mediated by Tri-metallic Complexes: A Dual Catalysis Strategy for Synthesis of Biodegradable Polyhydroxyalkanoates
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Polyhydroxyalkanoates (PHAs) are a unique class of commercially manufactured biodegradable polyesters with properties suitable for partially substituting petroleum-based plastics. However, high costs and low volumes of production have restricted their application as commodity materials. In this study, tri-metallic complexes were developed for carbonylative polymerization via a dual catalysis strategy, and 17 products of novel PHAs with up to 38.2 kg mol?1 Mn values were discovered. The polymerization proceeds in a sequential fashion, which entails the carbonylative ring expansion of epoxide to β-lactone and its subsequent ring-opening polymerization that occurs selectively at the O-alkyl bond via carboxylate species. The wide availability and structural diversity of epoxide monomers provide PHAs with various structures, excellent functionalities, and tunable properties. This study represents a rare example of the preparation of PHAs using epoxides and carbon monoxide as raw materials.
- Li, Wen-Bing,Liu, Ye,Lu, Xiao-Bing,Yang, Jin-Chuang,Yang, Jun
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supporting information
(2022/01/20)
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- Direct Heterogenization of Salphen Coordination Complexes to Porous Organic Polymers: Catalysts for Ring-Expansion Carbonylation of Epoxides
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Salen and salphens are important ligands in coordination chemistry due to their ability to form various metal complexes that can be used for a variety of organic transformations. However, salen/salphen complexes are difficult to separate from the reaction mixture, thereby limiting their application to homogeneous systems. Accordingly, considerable effort has been spent to heterogenize the metallosalen/salphen complexes; however, this has resulted in compromised activities and selectivities. Direct heterogenization of metallosalens to form porous organic polymers (POPs) shows promise for heterogeneous catalysis, because it would allow easy separation while retaining catalytic function. Thus, a facile synthetic strategy for preparing metallosalen/salphen-based porous organic polymers through direct molecular knitting using a Friedel-Crafts reaction is presented herein for the first time. As representative candidates, salphenM(III)Cl (M = Al3+ and Cr3+) complexes are knitted by covalent cross-linking using this facile, scalable, one-pot method to synthesize highly POPs in high yields. When incorporated with [Co(CO)4]- anions, the resulting heterogeneous Lewis acidic metal (Al3+ and Cr3+) POPs exhibit propylene oxide ring-expansion carbonylation activity on par with those of their homogeneous counterparts.
- Ganesan, Vinothkumar,Yoon, Sungho
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- Acrylonitrile Derivatives from Epoxide and Carbon Monoxide Reagents
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The present invention is directed to reactor systems and processes for producing acrylonitrile and acrylonitrile derivatives. In preferred embodiments of the present invention, the processes comprise the following steps: introducing an epoxide reagent and carbon monoxide reagent to at least one reaction vessel through at least one feed stream inlet; contacting the epoxide reagent and carbon monoxide reagent with a carbonylation catalyst to produce a beta-lactone intermediate; polymerizing the beta-lactone intermediate with an initiator in the presence of a metal cation to produce a polylactone product; heating the polylactone product under thermolysis conditions to produce an organic acid product; optionally esterifying the organic acid product to produce one or more ester products; and reacting the organic acid product and/or ester product with an ammonia reagent under ammoxidation conditions to produce an acrylonitrile product.
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-
Paragraph 0223-0237
(2019/01/15)
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- An aluminum(III) picket fence phthalocyanine-based heterogeneous catalyst for ring-expansion carbonylation of epoxides
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An effective heterogeneous catalyst for ring-expansion carbonylation of epoxides may have additional advantages over the homogeneous counterpart in terms of facile product separation and recyclability. A new Al(iii) picket fence phthalocyanine complex was synthesized and directly knitted using the Friedel-Crafts reaction to prepare a solid porous network, which was ultimately used to immobilize [Co(CO)4]- ions. The resulting heterogeneous catalyst, [Lewis acid]+[Co(CO)4]-, efficiently catalyzes the conversion of various epoxides into the corresponding β-lactones with high selectivity (99%) and stoichiometric conversion under mild reaction conditions, along with good functional group tolerance.
- Jiang, Jianwei,Yoon, Sungho
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p. 6120 - 6125
(2019/03/19)
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- Balancing between Heterogeneity and Reactivity in Porphyrin Chromium-Cobaltate Catalyzed Ring Expansion Carbonylation of Epoxide into β-Lactone
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The synthesis of a unique heterogeneous catalyst that combines the functionality of a homogeneous catalyst and the advantages of a heterogeneous catalytic process is a continuing goal in various industrially applicable reactions. Here, we report heterogenization of homogeneous catalyst for lactone production from epoxide carbonylation through a facile polymerization using Friedel-Crafts reaction. A correlation between reactivity and degree of heterogeneity has been deduced by synthesizing different sized polymeric catalysts. The partially polymerized catalyst showed a remarkable initial turnover frequency of 400 h-1, and the fully polymerized catalyst displayed excellent selectivity during recycling with a total turnover number of 4100.
- Rajendiran, Senkuttuvan,Ganesan, Vinothkumar,Yoon, Sungho
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supporting information
p. 3283 - 3289
(2019/05/15)
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- PROCESSES FOR PRODUCING BETA-LACTONE AND BETA-LACTONE DERIVATIVES WITH HETEROGENOUS CATALYSTS
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The present invention is directed to processes from producing beta-lactone and beta-lactone derivatives using heterogenous catalysts. In preferred embodiments of the present invention, the processes comprise the steps: passing a feed stream comprising an epoxide reagent and a carbon monoxide reagent to a reaction zone; contacting the epoxide reagent and the carbon monoxide reagent with a heterogenous catalyst to produce a beta-lactone product in the reaction zone; and removing the beta-lactone product from the reaction zone. In preferred embodiments, the heterogenous catalyst comprises a solid support containing a cationic Lewis acid functional group and a metal carbonyl compound comprising at least one of anionic metal carbonyl compound or a neutral metal carbonyl compound. In certain preferred embodiments, the epoxide reagent and carbon monoxide reagent have a biobased content.
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Paragraph 0193-0195
(2019/02/24)
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- Efficient synthesis of the ketone body ester (R)-3-hydroxybutyryl-(R)-3-hydroxybutyrate and its (S,S) enantiomer
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The ketone body ester (R)-3-hydroxybutyryl-(R)-3-hydroxybutyrate and its (S,S) enantiomer were prepared in a short, operationally simple synthetic sequence from racemic β-butyrolactone. Enantioselective hydrolysis of β-butyrolactone with immobilized Candida antarctica lipase-B (CAL-B) results in (R)-β-butyrolactone and (S)-β-hydroxybutyric acid, which are easily converted to (R) or (S)-ethyl-3-hydroxybutyrate and reduced to (R) or (S)-1,3 butanediol. Either enantiomer of ethyl-3-hydroxybutyrate and 1,3 butanediol are then coupled, again using CAL-B, to produce the ketone body ester product. This is an efficient, scalable, atom-economic, chromatography-free, and low cost synthetic method to produce the ketone body esters.
- Budin, Noah,Higgins, Erin,DiBernardo, Anthony,Raab, Cassidy,Li, Chun,Ulrich, Scott
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p. 560 - 564
(2018/07/25)
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- METHODS FOR PRODUCTION OF TEREPHTHALIC ACID FROM ETHYLENE OXIDE
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The present invention provides methods for the production of terephthalic acid and derivatives thereof using ethylene oxide, carbon monoxide and furan as feedstocks. The process is characterized by high yields and high carbon efficiency. The process can utilize 100% biobased feedstocks (EO via ethanol, CO via biomass gasification, and furan via known processes from cellulosic feedstocks).
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Page/Page column 26-28
(2017/01/23)
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- A covalent triazine framework-based heterogenized Al-Co bimetallic catalyst for the ring-expansion carbonylation of epoxide to β-lactone
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Difficulties in product separation and ineffective recycling of the homogenous catalyst deter the mass production of β-lactones via carbonylation of epoxides. Herein, we address these issues, for the first time, using a recyclable heterogenized catalyst [bpy-CTF-Al(OTf)2][Co(CO)4] that efficiently converts propylene oxide (PO) to β-butyrolactone with high selectivity.
- Rajendiran, Senkuttuvan,Natarajan, Prakash,Yoon, Sungho
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p. 4635 - 4638
(2017/01/29)
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- Acceptorless dehydrogenative lactonization of diols by Pt-loaded SnO2 catalysts
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We report herein a new heterogeneous catalytic system for dehydrogenative lactonization of various diols under solvent-free and acceptor-free conditions using 1 mol% of Pt-loaded SnO2, providing the first successful example of acceptorless lactonization of 1,6-hexanediol to ε-caprolactone by a heterogeneous catalyst. This journal is
- Touchy, Abeda Sultana,Shimizu, Ken-Ichi
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p. 29072 - 29075
(2015/04/14)
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- Lipase-catalyzed doubly enantioselective ring-opening resolution between alcohols and lactones: Synthesis of chiral hydroxyl esters with two stereogenic centers
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A novel lipase B from Candida antarctica-catalyzed doubly enantioselective ring-opening resolution between racemic alcohols and lactones was developed. By using this strategy, three optically pure compounds including hydroxyl esters with two stereogenic centers and recovered alcohols and lactones were obtained simultaneously in high yields and ee. This process was used for the resolution of various racemic alcohols with different substituent groups and lactones with different ring sizes (four- and seven- membered lactones). The scale-up experiments were also successful. Moreover, molecular docking was performed to explain the molecular basis of this doubly enantioselective ring-opening resolution. As an attractive and efficient strategy, lipase-catalyzed doubly enantioselective ring-opening resolution will be widely used in the synthesis of optically pure hydroxyl esters with two stereogenic centers. Opening new doors: A novel lipase B from Candida antarctica-catalyzed doubly enantioselective ring-opening resolution between racemic alcohols and lactones is developed.
- Xia, Bo,Li, Yanyan,Cheng, Guilin,Lin, Xianfu,Wu, Qi
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p. 3448 - 3454
(2015/04/16)
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- PROCESS FOR BETA-LACTONE PRODUCTION
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The present application provides a method for producing an beta-lactone product. The method includes the steps of: reacting an epoxide, a solvent with a carbonylation catalyst and carbon monoxide to produce a reaction stream comprising a beta-lactone then separating a portion of the beta-lactone in the reaction stream from the solvent and carbonylation catalyst to produce: i) a beta-lactone stream with the beta-lactone, and ii) a catalyst recycling stream including the carbonylation catalyst and the high boiling solvent; and adding the catalyst recycling stream to the feed stream.
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Page/Page column 20-21
(2012/05/21)
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- Comprehensive study of isobutane selective oxidation over group i and II phosphomolybdates: Structural and kinetic factors
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Various phosphomolybdates were synthesized using cations from Groups 1 and 2 of the periodic table. These compounds were of the form M x H 3-xn [PMo12O40], with n being the cationic charge (+1 or +2). XRD analysis shows pure phosphomolybdic acid has a triclinic structure. A body centered cubic (BCC) structure gradually develops with addition of Group 1 cations, and the triclinic phase is completely replaced by the BCC phase once metal cations occupy a volume greater than 9-11 A3 per phosphomolybdate anion. The Group 2 compounds do not form a cubic phase, however the triclinic phase distorts once cationic volume is greater about 5 or 6 A3 and appears to become somewhat amorphous. Isobutane selective oxidation over the compounds yielded methacrolein (primary product), 3-methyl-2-oxetanone (lactone), acetic acid, propene, methacrylic acid, carbon dioxide and water as products. Propene was formed over the Group 1 compounds exclusively and methacrylic acid formation was observed with BaH[PMo12O40] only. Products form via two distinct processes: Category 1 product has an exponential profile and coverage is consistent with a Langmuir model, Category 2 formations are consistent with desorptions from within the bulk of the substrates. Methacrolein forms via both Category 1 and 2 processes, whilst all other products are formed by Category 2 exclusively. A rigorous kinetic analysis yielded accurate activation parameters. Category 1 methacrolein formation apparent activation energies ranged from 34.7 ± 1.3 to 119 ± 4 kJ mol-1. Category 2 formations ranged from 34.3 ± 0.4 to 726 ± 172 kJ mol-1. No relationship between activity and composition or structure could be ascertained, despite investigation into correlations using several different models. Graphical Abstract: [Figure not available: see fulltext.]
- Kendel, Shane,Brown, Trevor
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experimental part
p. 1767 - 1785
(2012/03/08)
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- Rediscovering copper-based catalysts for intramolecular carbon-hydrogen bond functionalization by carbene insertion
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A series of TpxCu complexes (Tpx = hydrotrispyrazolylborate ligand) have been tested as catalysts for the decomposition of several diazoacetates and N,N-disubstituted diazoacetamides and the subsequent formation of lactones and lacta
- Martin, Carmen,Belderrain, Tomas R.,Perez, Pedro J.
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supporting information; scheme or table
p. 4777 - 4781
(2009/12/08)
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- On the way to biodegradable poly(hydroxy butyrate) from propylene oxide and carbon monoxide via β-butyrolactone: Multisite catalysis with newly designed chiral indole-imino chromium(III) complexes
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Enantioenriched poly(hydroxy butyrate) (PHB) is a biodegradable polyester of significant commercial interest as an environmentally benign substitute of commodity polyolefines. We report on the design and development of new chiral indole-based ligand families and on their chromium(III) complexes as enantioselective catalysts for the conversion of propylene oxide and carbon monoxide to enantioenriched β-butyrolactone, the key monomer for the production of PHB by ring-opening polymerization. The enantioselective carbonylation catalysts are based on new chiral tri- and tetradentate [N2O] and [N4] chromium(III) complexes containing chiral indolaldimine ligand scaffolds. The conceptual design of these ligands is inspired by Jacobsen's salicylaldimine lead structure; the key difference is an exchange of the salicyl-O-donor against an indole-N-donor, allowing additional structural diversity and stereoelectronic tuning by the indole substitution pattern. Synthetically, chiral indolealdimines are easily accessible from 7-formylindoles by standard Schiff base condensation with chiral amine building blocks; the 7-formylindoles in turn are synthesized from the corresponding 7-bromoindoles by the Rapoport synthesis, and the starting 7-bromoindoles are accessible from 2-bromoaniline by the classical Fischer indole synthesis. Three generations of chiral [N2O] and [N4] chromium(III) catalysts have been developed and evaluated in the enantioselective carbonylation of racemic propylene oxide with carbon monoxide using tetracarbonylcobaltate as the nucleophilic reagent for the insertion of carbon monoxide into the activated propylene oxide/chiral Lewis acid complex. The best catalyst out of 10 candidates showed at a temperature of 80 °C an activity of 37% conversion, 100% chemoselectivity, and 19% stereoselectivity.
- W?lfle, Heimo,Kopacka, Holger,Wurst, Klaus,Preishuber-Pflügl, Peter,Bildstein, Benno
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experimental part
p. 2493 - 2512
(2009/12/01)
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- Barium manganate in microwave-assisted oxidation reactions: synthesis of lactones by oxidative cyclization of diols
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Microwave irradiation of a range of diols at 150 °C in acetonitrile in the presence of three equivalents of barium manganate facilitates a novel tandem oxidation/heterocyclocondensation to give the corresponding lactone, including both small and medium ring lactones, in only one hour and in high yield without the need for chromatographic purification.
- Bagley, Mark C.,Lin, Zhifan,Phillips, David J.,Graham, Andrew E.
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experimental part
p. 6823 - 6825
(2010/04/27)
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- Catalytic double carbonylation of epoxides to succinic anhydrides: Catalyst discovery, reaction scope, and mechanism
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The first catalytic method for the efficient conversion of epoxides to succinic anhydrides via one-pot double carbonylation is reported. This reaction occurs in two stages: first, the epoxide is carbonylated to a β-lactone, and then the β-lactone is subsequently carbonylated to a succinic anhydride. This reaction is made possible by the bimetallic catalyst [(CITPP)Al(THF)2]+[Co(CO)4]- (1; CITPP = meso-tetra(4-chlorophenyl)porphyrinato; THF = tetrahydrofuran), which is highly active and selective for both epoxide and lactone carbonylation, and by the identification of a solvent that facilitates both stages. The catalysis is compatible with substituted epoxides having aliphatic, aromatic, alkene, ether, ester, alcohol, nitrile, and amide functional groups. Disubstituted and enantiomerically pure anhydrides are synthesized from epoxides with excellent retention of stereochemical purity. The mechanism of epoxide double carbonylation with 1 was investigated by in situ IR spectroscopy, which reveals that the two carbonylation stages are sequential and non-overlapping, such that epoxide carbonylation goes to completion before any of the intermediate β-lactone is consumed. The rates of both epoxide and lactone carbonylation are independent of carbon monoxide pressure and are first-order in the concentration of 1. The stages differ in that the rate of epoxide carbonylation is independent of substrate concentration and first-order in donor solvent, whereas the rate of lactone carbonylation is first-order in lactone and inversely dependent on the concentration of donor solvent. The opposite solvent effects and substrate order for these two stages are rationalized in terms of different resting states and rate-determining steps for each carbonylation reaction.
- Rowley, John M.,Lobkovsky, Emil B.,Coates, Geoffrey W.
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p. 4948 - 4960
(2008/02/03)
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- Carbonylative ring opening of terminal epoxides at atmospheric pressure
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(Chemical Equation Presented) The carbonylative opening of terminal epoxides under mild conditions has been developed using Co2-(CO) 8 as the catalyst. Under 1 atm of carbon monoxide and at room temperature in methanol, propylene oxide is converted to methyl 3-hydroxybutanoate in up to 89% yield. This transformation is general for many terminal epoxides bearing alkyl, alkenyl, aryl, alkoxy, chloromethyl, phthalimido, and acetal functional groups. The opening takes place without epimerization at the secondary stereocenter.
- Denmark, Scott E.,Ahmad, Moballigh
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p. 9630 - 9634
(2008/03/17)
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- Low pressure carbonylation of heterocycles
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Heterocycles, e.g., epoxides, are carbonylated at low pressure with high percentage conversion to cyclic, ring expanded products using the catalyst where L is tetrahydrofuran (THF).
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Page/Page column 4
(2008/06/13)
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- Practical β-lactone synthesis: Epoxide carbonylation at 1 atm
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A readily prepared bimetallic catalyst is capable of effecting epoxide carbonylation to produce β-lactones at substantially lower CO pressures than previously reported catalyst systems. A functionally diverse array of β-lactones is produced in excellent yields at CO pressures as low as 1 atm. This procedure allows for epoxide carbonylation on a multigram scale without the requirement of specialized, high-pressure equipment.
- Kramer, John W.,Lobkovsky, Emil B.,Coates, Geoffrey W.
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p. 3709 - 3712
(2007/10/03)
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- Synthesis of β-lactones: A highly active and selective catalyst for epoxide carbonylation
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A new highly active and selective catalyst for the synthesis of β-lactones from CO and epoxides is reported. The catalyst, [(N,N′-bis(3,5-di-tert-butylsalicylidene) phenylenediamino)Al(THF)2][Co(CO)4] ([(salph)Al(THF)2][Co(CO)4]) is easily prepared from the corresponding (salph)AlCl and NaCo(CO)4. At 50 °C and 880 psi of CO, the catalyst (1 mol %) carbonylates epoxides such as propylene oxide, 1-butene oxide, epichlorohydrin, and isobutylene oxide to the lactones β-butyrolactone, β-valerolactone, γ-chloro-β-butyrolactone, and β-methyl-β-butyrolactone in high yield. (R)-Propylene oxide was carbonylated to (R)-β-butyrolactone with retention of stereochemistry. Copyright
- Getzler, Yutan D. Y. L.,Mahadevan, Viswanath,Lobkovsky, Emil B.,Coates, Geoffrey W.
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p. 1174 - 1175
(2007/10/03)
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- [Lewis acid]+[Co(CO)4]- complexes: A versatile class of catalysts for carbonylative ring expansion of epoxides and aziridines
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Efficient carbonyl insertion into C-O and C-N bonds using [Lewis acid]+[Co(CO)4]- complexes 1 and 2 gives regio- and stereoselective carbonylation of a variety of epoxides and aziridines to yield β-lactones and β-lactams, respectively. Both transformations are proposed to occur by the same mechanism, yielding products with inversion of configuration at the site of CO insertion.
- Mahadevan, Viswanath,Getzler, Yutan D. Y. L.,Coates, Geoffrey W.
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p. 2781 - 2784
(2007/10/03)
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- Synthesis of β-lactones by the regioselective, cobalt and Lewis acid catalyzed carbonylation of simple and functionalized epoxides
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The PPNCo(CO)4 and BF3·Et2O catalyzed carbonylation of simple and functionalized epoxides in DME gives the corresponding β-lactones regioselectively in good to high yields. The carbonylation occurred selectively at the uns
- Lee, Jong Tae,Thomas,Alper
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p. 5424 - 5426
(2007/10/03)
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- Amino acid nitrosation products as alkylating agents
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Nitrosation reactions of α-, β-, and γ-amino acids whose reaction products can act as alkylating agents of DNA were investigated. To approach in vivo conditions for the two-step mechanism (nitrosation and alkylation), nitrosation reactions were carried ou
- Garcia-Santos,Calle,Casado
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p. 7506 - 7510
(2007/10/03)
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- Ruthenium-I0D0-optically active phosphine complex
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This invention is concerned with a ruthenium-iodo-optically active bidentate phosphine complex of the formula (I):[Ru-(I)q-(T1)n(SOL)r(L)]m(T2)p(I)s(I)wherein T1 represents a carboxylic acid anion, SOL represents a polar solvent, L represents an optically active bidentate phosphine ligand, T2 represents an anion different from halogen atom anions and carboxylic acid anions, n denotes 0 or 1, r denotes 0, 3 or 4, m denotes 1 or 2, q denotes 0 or 1, or where m is 2, q may represent 1 or 1.5, p denotes 0 or 1, and s denotes 0, 1 or 2 is prepared. Said phosphine complex is usefull as an efficient catalyst for asymmetrically hydrogenating 4-methylene-2-oxetanone into optically active 4-methyl-2-oxetanone.
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- Lipase promoted asymmetric trans-esterification of 4-alkyl-, 3-alkyl- and 3,4-dialkyloxetan-2-ones with ring-opening
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Kinetic resolution of(+/-)-4-substituted [(+/-)-1], 3-substituted [(+/-)-4] and 3,4-disubstituted oxetan-2-ones [(+/-)-7] was effected by the action of lipases in organic solvents. The substrates (+/-)-1, (+/-)-4 and (+/-)-7 were prepared by [2 + 2] cycloaddition of aldehydes with ketene, intramolecular substitution of 3-bromoalkanoic acids and the Adam's cyclization of anti- and syn-3-hydroxyalkanoic acids, respectively. Lipase PS exhibited good activity towards all the oxetanones and was employed for the resolution experiments except with (+/-)-4-methyloxetan-2-one (+/-)-1a for which PPL was used. The stereoselectivity was satisfactory for obtaining oxetan-2-ones of high ee's except for a few cases. The configuration of new compounds was established by chemical correlation and CD spectroscopy.
- Sakai, Naoko,Ageishi, Satoru,Isobe, Hiroshi,Hayashi, Yoshiyuki,Yamamoto, Yukio
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- Lipase-promoted asymmetric transesterification of 4-alkyloxetan-2-ones with ring-opening
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Lipase-catalysed reaction of (+/-)-4-alkyloxetan-2-ones 1a-c with benzyl alcohol gave (R)-1a (R=Me) (36percent, 96percent ee) and benzyl (S)-3-hydroxybutanoate 2a (51percent, 85percent ee), (R)-1b (R=Pr) (42percent, 75percent ee) and benzyl (S)-3-hydroxyhexanoate 2b (45percent, 69percent ee) and (S)-1c (R=Pr-i, 41percent, 95percent ee) and benzyl (R)-3-hydroxy-4-methylpentanoate 2c (43percent, 90percent ee), respectively.
- Koichi, Yota,Suginaka, Kaoru,Yamamoto, Yukio
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p. 1645 - 1646
(2007/10/02)
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- Asymmetric Hydrogenation of Olefins with Aprotic Oxygen Functionalities Catalyzed by BINAP-Ru(II) Complexes
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Cyclic α,β-unsaturated ketones, alkylidene lactones, and alkenyl ethers have been hydrogenated in high enantiomeric excesses by use of BINAP-Ru(II) complexes (BINAP = 2,2'-bis(diphenylphosphino)-1,1'-binaphthyl) as catalysts. 2-Alkylidenecyclopentanones were hydrogenated in the presence of Cl, Ru2Cl4(BINAP)2(NEt3), or Ru(OCOCH3)2(BINAP) in up to 98percent ee, while in the case of 2-benzylidene- and 2-(3-phenylpropylidene)cyclopentanones, enantiomeric excesses of the hydrogenation were below 50percent under the same conditions.The sense of asymmetric induction as well as the enantioselectivity (95percent ee) obtained in the hydrogenation of (E)-2-propylidene-γ-butyrolactone were the same as those of the (Z)-isomer.Lactones, 2- and 4-alkylidene-γ-butyrolactones, were converted to the corresponding saturated γ-butyrolactones in 95percent ee.Hydrogenation of diketene with the catalytic system derived from (benzene)>Cl and triethylamine or complex Ru2Cl42(NEt3) established a new synthetic route to (R)-4-methyl-2-oxetanone, a promising monomer of biodegradable polymers, in up to 97percent selectivity and 92percent ee.Alkenyl ethers, 2-methylenetetrahydrofuran, and 2-methyl-3,4-dihydrofuran have also been hydrogenated to give 2-methyltetrahydrofuran in 91 and 87percent ee, respectively.
- Ohta, Tetsuo,Miyake, Tsutomu,Seido, Nobuo,Kumobayashi, Hidenori,Takaya, Hidemasa
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p. 357 - 363
(2007/10/02)
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- Process for preparing optically active 4-methyl-2-oxetanone
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A process for preparing optically active 4-methyl-2-oxetanone which comprises asymmetrically hydrogenating 4-methylene-2-oxetanone in the presence of a ruthenium-optically active phosphine complex. Optically active 4-methyl-2-oxetanone can easily and economically be obtained at high optical purity.
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- Asymmetric Cycloaddition of Ketene with Aldehydes catalysed by Chiral Bissulfonamide-Trialkylaluminium Complexes
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Asymmetric cycloaddition of ketene with the aldehydes 1a-g, catalysed by 10 molpercent of C2-symmetric bissulfonamide 2a-c-R3Al complexes afforded optically active 4-substituted oxetan-2-ones 3a-g in up to 74percent enantiomeric excess.
- Tamai, Yasufumi,Yoshiwara, Hideki,Someya, Masahiro,Fukumoto, Jun,Miyano, Sotaro
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p. 2281 - 2282
(2007/10/02)
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- Process for preparing optically active 4-methyl-2-oxetanone
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A process for preparing optically active 4-methyl-2-oxetanone which comprises asymmetrically hydrogenating 4-methylene-2-oxetanone in the presence of a ruthenium-optically active phosphine complex. Optically active 4-methyl-2-oxetanone can easily and economically be obtained at high optical purity.
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- An Efficient Synthesis of Optically Active 4-Methyloxetan-2-one: Asymmetric Hydrogenation of Diketene catalysed by binap-Ruthenium(II) Complexes
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Highly enantioselective hydrogenation of diketene with the catalytic system derived from (benzene)>Cl and triethylamine or with Ru2Cl42(NEt3) in tetrahydrofuran gives optically active 4-methyloxetan-2-one in up to 97percent selectivity and 92percent enantiomeric excess (e.e.).
- Ohta, Tetsuo,Miyake, Tsutomu,Takaya, Hidemasa
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p. 1725 - 1726
(2007/10/02)
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- DISTRIBUTION OF β-LACTONES BETWEEN AQUEOUS AND ORGANIC PHASES
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Distribution coefficients of β-lactones between aqueous and organic phases are determined by the electrophilicity of the organic extractant, but a satisfactory quantitative relation between the distribution coefficients and the properties of organic solvents can be obtained only by a multiparameter equation that takes various solvation processes into account.The distribution of β-lactones between aqueous and organic phases can be described by the equation (corg)n/(cH2O) = const.
- Kotovich, Kh. Z.,Makitra, R. G.,Pirig, Ya. N.,Khorunzha, Ya. M.
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p. 445 - 451
(2007/10/02)
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- Manufacture of gamma-crotonolactone by carbonylation of glycidol
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A process for preparing a substituted or unsubstituted gamma-crotonolactone is provided which comprises reacting a substituted or unsubstituted glycidol of the formula: STR1 wherein R1, R2, R3 and R4 are the same or different and are H, alkyl of from 1 to 40 carbon atoms or aryl of from 6 to 18 carbon atoms, with carbon monoxide in the presence of a carbonylation catalyst to provide a corresponding beta-hydroxy lactone of the formula: STR2 and dehydrating said beta-hydroxy lactone to provide the corresponding gamma-crotonolactone of the formula: STR3
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