24079-79-6Relevant academic research and scientific papers
PROCESS FOR PREPARING CARBAMOYLOXYMETHYL TRIAZOLE CYCLOHEXYL ACID COMPOUNDS
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Page/Page column 85, (2020/10/27)
Improved methods and intermediates thereof for preparing carbamoyloxy methyl triazole cyclohexyl acid compounds are described. These compounds are useful as LPA antagonists. Formula (I).
Scalable and Chemoselective Synthesis of ?-Keto Esters and Acids via Pd-Catalyzed Carbonylation of Cyclic β-Chloro Enones
Kaplan, Justin M.,Hruszkewycz, Damian P.,Strambeanu, Iulia I.,Nunn, Christopher J.,Vangelder, Kelsey F.,Dunn, Anna L.,Wozniak, Derek I.,Dobereiner, Graham E.,Leitch, David C.
supporting information, p. 85 - 96 (2018/09/25)
The Pd-catalyzed carbonylation of cyclic β-chloro enones using simple phosphine ligands is described. Screening identified P(Me)(t-Bu)2 as the most general ligand for an array of chloro enone electrophiles. The reaction scope has been evaluated on a milligram scale across 80 examples, with excellent reactivity observed in nearly every case. Carbonylation can be achieved even in the presence of potentially sensitive or inhibitory functional groups, including basic nitrogens as well as aryl chlorides or bromides. Twenty examples have been run on a gram scale, demonstrating scalability and practical utility. Using P(Me)(t-Bu)2, the reaction rate depends on both nucleophile and electrophile identity, with completion times varying between 3 and >18 h under a standard set of conditions. Switching to P(t-Bu)3 for the carbonylation of 3-chlorocyclohex-2-enone with methanol results in a dramatic rate increase, enabling effective catalysis with kinetics consistent with rate-limiting mass transfer. Stoichiometric oxidative addition of 3-chlorocyclohex-2-enone and 3-oxocyclohex-1-enecarbonyl chloride to both Pd[P(t-Bu)3]2 and Pd(PCy3)2 has enabled characterization and isolation of several potential catalytic intermediates, including Pd-vinyl and Pd-acyl species supported by P(t-Bu)3 and PCy3 ligands. Monitoring the oxidative addition of 3-chlorocyclohex-2-enone to Pd(PCy3)2 by NMR spectroscopy indicates that coordination of the alkene precedes oxidative addition. As a result of these studies, methyl 3-oxocyclohex-1-enecarboxylate has been synthesized via Pd-catalyzed carbonylation of 3-chlorocyclohex-2-enone in 90% yield on a 60 g scale with only 0.5 mol % catalyst loading.
Allylic oxidations catalyzed by dirhodium caprolactamate via aqueous tert-butyl hydroperoxide: The role of the tert-butylperoxy radical
McLaughlin, Emily C.,Choi, Hojae,Wang, Kan,Chiou, Grace,Doyle, Michael P.
supporting information; experimental part, p. 730 - 738 (2009/07/04)
Dirhodium(II) caprolactamate exhibits optimal efficiency for the production of the tert-butylperoxy radical, which is a selective reagent for hydrogen atom abstraction. These oxidation reactions occur with aqueous tert-butyl hydroperoxide (TBHP) without rapid hydrolysis of the caprolactamate ligands on dirhodium. Allylic oxidations of enones yield the corresponding enedione in moderate to high yields, and applications include allylic oxidations of steroidal enones. Although methylene oxidation to a ketone is more effective, methyl oxidation to a carboxylic acid can also be achieved. The superior efficiency of dirhodium(II) caprolactamate as a catalyst for allylic oxidations by TBHP (mol % of catalyst, % conversion) is described in comparative studies with other metal catalysts that are also reported to be effective for allylic oxidations. That different catalysts produce essentially the same mixture of products with the same relative yields suggests that the catalyst is not involved in product-forming steps. Mechanistic implications arising from studies of allylic oxidation with enones provide new insights into factors that control product formation. A previously undisclosed disproportionation pathway, catalyzed by the tert-butoxy radical, of mixed peroxides for the formation of ketone products via allylic oxidation has been uncovered.
Allylic Oxidations Catalyzed by Dirhodium Catalysts under Aqueous Conditions
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Page/Page column 12, (2009/04/24)
The present invention relates to compositions and methods for achieving the efficient allylic oxidation of organic molecules, especially olefins and steroids, under aqueous conditions. The invention concerns the use of dirhodium (II,II) “paddlewheel complexes, and in particular, dirhodium carboximate and tert-butyl hydroperoxide as catalysts for the reaction. The use of aqueous conditions is particularly advantageous in the allylic oxidation of 7-keto steroids, which could not be effectively oxidized using anhydrous methods, and in extending allylic oxidation to enamides and enol ethers.
SPECIFITY OF E. COLI SHIKIMATE DEHYDROGENASE TOWARDS ANALOGUES OF 3-DEHYDROSHIKIMIC ACID
Bugg, Timothy D. H.,Abell, Chris,Coggins, John R.
, p. 6779 - 6782 (2007/10/02)
Analogues of 3-dehydroshikimic acid which lack the C-4 and C-5 hydroxyl groups have been synthesised and assayed as substrates for shikimate dehydrogenase.The presence of the C-4 hydroxyl group is found to be very important for specificity, whereas the C-5 hydroxyl group is not.The enzyme exhibits enantioselectivity at C-1 and C-4 of the racemic substrate analogues.
CHIRAL INDUCTION IN PHOTOCHEMICAL REACTIONS-V. REGIO- AND DIASTEREOSELECTIVITY IN THE PHOTOCHEMICAL CYCLOADDITION OF CHIRAL CYCLENONE-3-CARBOXYLATE WITH 1,1'-DIETHOXYETHENE
Herzog, Heinz,Koch, Hartmut,Scharf, Hans-Dieter,Runsink, Jan
, p. 3547 - 3558 (2007/10/02)
The chiral cyclenone-3-carboxylate 5-12 induce high regio - but only fair diastereoselectivities in the photochemical cycloaddition with 1,1'-diethoxyethene 23.Cyclohex-2-ene-1-one-3-carboxylates gain higher diastereoselectivites compared to the rin
Use of Protected β-Bromocyclopentenones and β-Bromocyclohexenones as β-Acylvinyl Anion Equivalents
Shih, Chuan,Swenton, John S.
, p. 2825 - 2832 (2007/10/02)
Ethylene glycol ketals of the 3-bromocyclohex-2-en-1-one as well as its 2-methyl, 2-n-propyl, and 5,5-dimethyl derivatives have been prepared, and their reactions with butyllithium were studied.The organolithium reagents derived from the above compounds react with a variety of electrophiles to afford after acid hydrolysis the corresponding 3-substituted cyclohexenones.Attempts to prepare the ethylene glycol ketal of 2-methyl-3-bromocyclopent-2-en-1-one gave a low yield of the bromoketal.However, dithioketals of 3-bromocyclopent-2-en-1-one and its 2-methyl derivativecould be prepared in good yield.The metalation chemistry of the dithioketals in both the five- and six-membered-ring series was examined.The functionalization chemistry of the resulting organolithium compounds afforded after dithioketal hydrolysis 3-functionalized cyclohex-2-en-1-ones and cyclopent-2-en-1-ones.Several limitations of the chemistry using allyl bromide and cyclohexenone as electrophiles are noted.
An Efficient and Simple β-Acylvinyl Anion Equivalent for Cyclohexenones
Shih, Chuan,Swenton, John S.
, p. 4217 - 4220 (2007/10/02)
Dilithio species available from treatment of Δ3,4-3-bromocyclohexenone ketals with two equivalents of n-butyllithium serve as one-pot equivalents of β-vinyl-carbanions of cyclohexenones.These former ketals are available in good yield from the corresponding β-bromocyclohexenone by direct ketalization under controlled conditions.
