- A Solid-Phase Assisted Flow Approach to In Situ Wittig-Type Olefination Coupling
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Described herein is the development of a continuous flow, solid-phase triphenylphosphine (PS-PPh3) assisted protocol to facilitate the in situ coupling of reciprocal pairs of halogen and carbonyl functionalised molecular pairs by a Wittig olefination within 15 mins. The protocol entails injecting a single solution (1 : 1 CHCl3 : EtOH) containing the halogenated and carbonyl-based substrates into a continuously flowing stream of CHCl3 : EtOH (1 : 1), passed through a fixed bed of K2CO3 and PS-PPh3. With advancement to the previous PS-PPh3 coupling procedures, the method employs a traditional polystyrene-based immobilisation matrix, the substrate scope of the protocol extended to substituted ketones, secondary alkyl chlorides, and an unprotected maleimide scaffold.
- Aldrich-Wright, Janice R.,Dankers, Christian,Gordon, Christopher P.,Polyzos, Anastasios,Tadros, Joseph
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supporting information
p. 4184 - 4194
(2021/08/24)
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- Pd-catalyzed regioselective C?H alkenylation and alkynylation of allylic alcohols with the assistance of a bidentate phenanthroline auxiliary
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A Pd-catalyzed regioselective C?H alkenylation of allylic alcohols with electron-deficient alkenes has been developed. The key to success is the introduction of bidentately coordinating phenanthroline directing group, which enables the otherwise challenging and regioselective C?H activation at the proximal alkenyl C?H bonds over the conceivably competitive allylic C?O bond activation. The same Pd/phenanthroline system is efficient for the C?H alkynylation of allylic alcohols with alkynyl bromides.
- Hirano, Koji,Miura, Masahiro,Xu, Shibo
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supporting information
p. 9059 - 9064
(2020/12/02)
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- 3-PHOSPHOGLYCERATE DEHYDROGENASE INHIBITORS AND USES THEREOF
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The present invention provides compounds, compositions thereof, and methods of using the same.
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Paragraph 00325
(2017/09/27)
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- Photocycloaddition of 3-alkenyloxy-2-cycloalkenones: Enantioselective lewis acid catalysis and ring expansion
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By application of substoichiometric amounts (50 mol %) of a chiral Lewis acid, the intramolecular [2+2] photocycloaddition of the title compounds was achieved with high enantioselectivity (up to 94 % ee). Upon cleavage of the cyclobutane ring the resulting tricyclic products underwent ring-expansion reactions under acidic conditions and formed anellated seven- or eight-membered-ring systems without racemization. The ring expansion could be combined with a diastereoselective reduction (triethylsilane) or allylation (allyltrimethylsilane) upon BF3 catalysis (48-87 % yield). Ring-a-ring o'roses: An enantioselective, Lewis acid catalyzed [2+2] photocycloaddition (9 examples, 69-94 % yield, up to 94 % ee) leads to tricyclic products, in which the marked bond of the cyclobutane ring can be cleaved to form medium-sized rings as shown in the example above.
- Brimioulle, Richard,Bach, Thorsten
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supporting information
p. 12921 - 12924
(2016/02/18)
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- BICYCLIC -AMINO ACID DERIVATIVE
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It is intended to provide a bicyclic γ-amino acid derivative having excellent activity as an α2δ ligand. The present invention provides a compound represented by the general formula (I): wherein R1, R2, R2', R4, R5, R6, R7, R8, and R8' are a hydrogen atom or the like; and R3 is a hydrogen atom, a halogen atom, a C1-C6 alkyl group, or the like.
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Page/Page column 54
(2010/06/17)
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- Asymmetric dihydroxylation of β,γ-unsaturated carboxylic esters with trisubstituted C=C bonds - Enantioselective syntheses of trisubstituted γ-butyrolactones
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β,γ-Unsaturated esters with stereodefined trisubstitued C=C double bonds were prepared by the Arndt-Eistert homologation of α,β-unsaturated carboxyl halides, by two-step methoxycarbonylation of allylbarium reagents, by deconjugation of α,β-unsaturated esters, and by Horner-Wadsworth-Emmons variants of the Stobbe condensation. Sharpless asymmetric dihydroxylation of the β,γ-unsaturated esters, followed by spontaneous cyclization, afforded β-hydroxy-γ-lactones in moderate to good yields and with enantiomeric excesses of up to 97 %. Similarly, tetrahydroxy-γ-lactones were obtained from diunsaturated esters; these lactones were converted into a bislactone and an unsaturated β-hydroxy γ-lactone. Wiley-VCH Verlag GmbH & Co. KGaA, 2006.
- Kapferer, Tobias,Brueckner, Reinhard
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p. 2119 - 2133
(2007/10/03)
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- Behaviour of unsaturated methyl esters with cyclopentaneacetic acid skeleton in the presence of mild lewis acids. Alkylation versus addition and lactonization
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The reactions of methyl 2-and 3-cyclopentenylacetate, 2-Me and 3-Me, in the presence of AlCl3/CH3NO2 or FeCl3 in benzene or in nitromethane were studied. The major products obtained in benzene were the kinetically controlled benzene alkylation compounds (6-Me as major and trans-and cis-5-Me as minor phenylated products) and the unexpected lactone 7 and hydroxyester 8. In order to understand the pathway in which the last products are formed, we made the unsaturated esters react in the absence of the aromatic substrate, in nitromethane. There are three types of products: double bond isomerization products (1-, 2-and 3-Me), H2O and HCl addition products (8 and 9) and lactone 7. The proton traces in the reaction medium cannot explain the good yields of the two last types of products. Therefore, it seems possible that the reaction may occur in two steps, (a) in the mixture of esters and catalyst and (b) during the decomposition in aqueous HCl solution. In step (a), an advanced charge polarization takes place under the influence of the Lewis acidity of the catalyst and also of the favourable steric assistance of the oxygen nonbonding pair of electrons in carbomethoxy group. In step (b), the formed complexes react with H2O and HCl to produce the addition compounds and the lactone. The key intermediate in the formation of 8 is probable an organometallic compound, I, (represented for the ester 2-Me in Scheme 1). Its precursor is a transition state, TS1, which is formed as a result of the redistribution of the oxygen nonbonding electrons and of the πC=C electrons at the same time with the implication of the metal catalyst's vacant orbital.
- Rǎzus, Alexandru C.,Nae, ?tefania,Stanciu, Cornel
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p. 801 - 807
(2007/10/03)
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- Conjugate Addition Reactions Mediated by Samarium(II) Iodide
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Samarium(II) iodide in conjunction with a catalytic low-valent transition metal species has been employed to promote the conjugate addition reaction of primary and secondary alkyl halides onto α,β-unsaturated esters and amides. The method has been determined to be quite general and hence has been extended to the cyclization reactions of alkyl halides onto α,β-unsaturated lactones, lactams, and nitriles. The cyclization reactions described herein provide a very general approach to the synthesis of functionalized carbocycles from simple acyclic precursors with excellent diastereoselectivity and under very mild reaction conditions.
- Molander, Gary A.,Harris, Christina R.
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p. 7418 - 7429
(2007/10/03)
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- Stereoselective Synthesis of Substituted Oxetanes
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The stereospecific synthesis of substituted oxetanes was shown to be feasible through the use of a deconjugative aldol-cyclization sequence.
- Galatsis, Paul,Parks, Daniel J.
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p. 6611 - 6614
(2007/10/02)
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- A new procedure for Horner-Wadsworth-Emmons olefination of carbonyl compounds
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Aldehydes undergo an efficient E-stereoselective Horner-Wadsworth-Emmons olefination by generation of phosphonate carbanion with lithium hydroxide. The reaction proceeds satisfactorily with linear, cyclic, polifunctional ketones in the presence of activated zeolites and by the slow addition of the base.
- Bonadies, Francesco,Cardilli, Antonella,Lattanzi, Alessandra,Orelli, Liliana R.,Scettri, Arrigo
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p. 3383 - 3386
(2007/10/02)
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- EFFICIENT OLEFINATION WITH α-ALKYL CYCLIC PHOSPHONAMIDES
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A variety of acyclic and cyclic aldehydes and ketones can be converted into the corresponding alkylidene, benzylidene and methoxycarbonyl alkylidene derivatives by treatment with 1,3,2-diazaphospholidine-2-alkyl-1,3-dimethyl 2-oxides (α-alkyl cyclic phosphonamides) under mild conditions.This olefination method is particularly useful in the case of enolizable carbonyl compounds.
- Hanessian, Stephen,Bennani, Youssef L.,Leblanc, Yves
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p. 1411 - 1424
(2007/10/02)
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- REACTIONS DU TYPE FRIEDEL-CRAFTS DE CERTAINS ACIDES INSATURES SUR LE BENZENE XV. CONTROLE CINETIQUE DE LA REACTION DES ACIDES INSATURES CYCLIQUES
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It was studied the reaction of the cyclopentylidene- and cyclopentylacetic acids and the lactone of the cis-hydroxy-2-cyclopentaneacetic acid with the benzene in the presence of aluminium chloride complexed with nitromethane or iron(III) chloride as catalyst. In these conditions the rearrangement of the reaction products was quite limitted. The reaction products were identified and a reaction mechanism was proposed.
- Razus, Alexandru C.,Arvay, Zsolt,Birzan, Liviu,Nae, Stefania
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p. 1259 - 1266
(2007/10/03)
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- 98. A Regioselective Cyclohexannulation Procedure via Dienamine Cycloaddition. Synthesis of Functionalised Decalins
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A regioselective cyclohexannulation procedure, whose key step involves the cycloaddition of dienamines 12-24 with methyl acrylate, allows the conversion of cycloalkanones 1-11 to bicyclic dienoates 25-37.The chemistry of 26 is briefly examined and, in the context of organoleptic studies concerning functionalised 5,5,9-trimethyldecalins, the transformation of 37 to ketones 44 and 46 as well as to acetates 53-56 is described.
- Snowden, Roger L.,Linder, Simon M.,Wuest, Manfred
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p. 892 - 905
(2007/10/02)
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- Cyclopentadienylideneethenone: Pyrolytic Generation and Argon Matrix Infrared Spectroscopic Study
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Two previously reported pyrolytic precursors for cyclopentadienylideneethenone (4) and benzyne produced two strong infrared bands attributable to ketene type compounds when their pyrolysates were examined by argon matrix isolation spectroscopy.To determine which band should be assigned to (4), four new precursors for (4) and benzyne and two analogues labelled with 13C at the carbonyl group have been synthesized.Precursors (8) and (14) are respectively a caged system and a bridged system bearing a mixed anhydride with trifluoroacetic acid.Flash vacuum pyrolysis of (8) and (14) at 600-700 deg with trapping at 77 K gave pyrolysates which contaned biphenylene.Pyrolysis of (8) and (14) at 600-700 deg in a stream of argon followed by deposition as an argon matrix at about 10 K showed that both produced a pyrolysate absorbing at 2089 cm-1 assigned to (4).Precursors (24) and (25) and the previously reported (18) and (27) are Meldrum's acid derivatives designed to yield the hypothetical cyclopentadienylide Meldrum's acid (19) by cage fission or retro-Diels-Alder reaction.They all gave their biphenylene on flash vacuum pyrolysis at 600-700 deg and their pyrolysates in argon matrices showed absorption both at 2089 cm-1 due to (4) and at 2225 cm-1 due to an unidentified ketene.The frequency shift resulting from substitution of 13C in the carbonyl group (52 cm-1) is in accordance with the assignment of the 2089 cm-1 band to (4).The pyrolysates from precursors (8a), (14), (18a), (25) and (27) were allowed to react with methanol and the resulting mixtures were hydrogenated.In all cases methyl cyclopentylacetate was obtained.
- Brown, Roger F. C.,Browne, Neil R.,Coulston, Karen J.,Eastwood, Frank W.,Irvine, Margaret J.,et al.
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p. 1321 - 1344
(2007/10/02)
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- DIENAMINES AS DIELS-ALDER DIENES. AN EFFICIENT CYCLOHEXANNULATION SEQUENCE.
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An efficient cyclohexannulation sequence is described whose key step involves a Diels-Alder reaction between an (E)-dienamine and methyl acrylate.
- Snowden, Roger L.,Wuest, Manfred
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p. 699 - 702
(2007/10/02)
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- Mechanism of Fragmentation of Alkylidene-Meldrum's Acids. Carboxyketene, Vinylketene, and Methyleneketene Intermediates from 5-Cyclopentylidene-2,2-dimethyl-1,3-dioxane-4,6-dione
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Three ketenes were successively observed on flash vacuum pyrolysis of 5-cyclopentylidene-2,2-dimethyl-1,3-dioxane-4,6-dione (5), viz., carboxycyclopentenylketene (11, 2126 cm-1), cyclopentylideneketene (12, 2087 cm-1), and cyclopentenylketene (13, 2110 cm-1). 11 was thermally converted to 13 and probably also to 12. 12 itself rearranged thermally to 13.The three ketenes were trapped with methanol to give the esters 14, 15, and 16. 14 was thermally unstable, rearranging at room temperature to methyl cyclopentylidenemalonate (14a) and decarboxylating at 150 deg C, predominantly to 16.A dimer of 12, 2,4-bis(cyclopentylidene)cyclobutane-1,3-dione (17), was also isolated. 1-Cyclopentenyldiazomethane (18) was prepared and pyrolyzed to 1,3-cyclohexadiene and benzene.No evidence for the formation of cyclohexyne (17) was obtained in any of these experiments.
- Wentrup, Curt,Gross, Gerhard,Berstermann, Hans-Michael,Lorencak, Primoz
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p. 2877 - 2881
(2007/10/02)
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- Cyclopentane derivatives useful as perfuming agents
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Cyclopentane derivatives useful as odor-modifying ingredients for manufacturing perfumes and perfumed products and perfume compositions containing same.
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