- Photoinduced Hydrocarboxylation via Thiol-Catalyzed Delivery of Formate across Activated Alkenes
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Herein we disclose a new photochemical process to prepare carboxylic acids from formate salts and alkenes. This redox-neutral hydrocarboxylation proceeds in high yields across diverse functionalized alkene substrates with excellent regioselectivity. This operationally simple procedure can be readily scaled in batch at low photocatalyst loading (0.01% photocatalyst). Furthermore, this new reaction can leverage commercially available formate carbon isotologues to enable the direct synthesis of isotopically labeled carboxylic acids. Mechanistic studies support the working model involving a thiol-catalyzed radical chain process wherein the atoms from formate are delivered across the alkene substrate via CO2?- as a key reactive intermediate.
- Alektiar, Sara N.,Wickens, Zachary K.
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supporting information
p. 13022 - 13028
(2021/09/03)
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- Pyridineacetamide derivative serving as CDK inhibitor, and preparation method and application thereof
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The invention belongs to the technical field of pyridineacetamide derivatives, and particularly relates to a pyridineacetamide derivative serving as a CDK inhibitor and a preparation method and application of the pyridine acetamide derivative. The pyridineacetamide derivative shows excellent CDK9/CDK7 enzyme inhibitory activity, and can be used for preparing drugs used for treating cancers, especially hematologic cancers including acute myeloid leukemia, multiple myeloma, chronic lymphocytic leukemia, follicular lymphoma and the like and solid tumors such as breast cancer, prostate cancer, ovarian cancer, hepatocellular carcinoma, pancreatic cancer, kidney cancer, stomach cancer, colorectal cancer, lung cancer and the like.
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Paragraph 0603-0609
(2021/07/28)
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- Scalable synthesis of the aroma compounds d6-β-ionone and d6-β-cyclocitral for use as internal standards in stable isotope dilution assays
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C13 Norisoprenoids are important aroma compounds in wine, giving positive attributes to the overall wine aroma even when found at very low levels. β-Ionone is considered one of the most important aroma compounds giving violet, woody and raspberry aromas to wine, fruits and vegetables in which it is found. Due to its potent aroma at low levels, precise analytical methods are desired for its quantification. Stable isotope dilution assay (SIDA) is one of the most important of these methods but requires the use of isotopically labelled standards. Herein, we describe the scalable synthesis of d6-β-ionone and d6-β-cyclocitral, another aroma compound with smokey and fruity notes, starting from the relatively inexpensive deuterated starting material d6-acetone.
- Mosaferi, Shabnam,Jelley, Rebecca E.,Fedrizzi, Bruno,Barker, David
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supporting information
(2020/12/02)
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- Visible-Light-Promoted Intramolecular α-Allylation of Aldehydes in the Absence of Sacrificial Hydrogen Acceptors
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We report herein an unprecedented protocol for radical cyclization of aldehydes with pendant alkenes via synergistic photoredox, cobaloxime, and amine catalysis. The transformation was achieved in the absence of external oxidants, providing a variety of 5-, 6-, and 7-membered ring products with alkene transposition in satisfactory yields. The reaction exhibits wide functional group compatibility and occurs under mild conditions with extrusion of H2.
- Liu, Feng,Liu, Jia-Li,tu, Jia-Lin
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supporting information
p. 7369 - 7372
(2020/10/05)
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- Synergistic N-Heterocyclic Carbene/Palladium-Catalyzed [3 + 2] Annulation of Vinyl Enolates with 1-Tosyl-2-vinylaziridine
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The synergistic combination of N-heterocyclic carbene organocatalysis and transition-metal catalysis for a formal [3 + 2] annulation between 3-substituted but-2-enoates and 1-tosyl-2-vinylaziridine was developed. This cooperative strategy provides a facile and efficient access to various functionalized (E)-3-ethylidene-4-vinylpyrrolidin-2-ones in a regioselective and stereoselective manner. The preliminary asymmetric studies were also performed, which indicated a potential for enantioselective annulation of vinyl enolate intermediates with transition-metal-π-allyl species.
- Gao, Jian,Zhang, Jianming,Fang, Shuaishuai,Feng, Jie,Lu, Tao,Du, Ding
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supporting information
p. 7725 - 7729
(2020/10/09)
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- Boron-Templated Dimerization of Allylic Alcohols to Form Protected 1,3-Diols via Acid Catalysis
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We report an unprecedented boron-templated dimerization of allylic alcohols that generates a 1,3-diol product with two stereogenic centers in high yield and diastereoselectivity. This acid-catalyzed reaction is achieved via in situ formation of a boronic ester intermediate that facilitates selective cyclization and formation of a cyclic boronic ester product. High yields are observed with a variety of allylic alcohols, and mechanistic studies confirm the role of boron as a template for the reaction.
- Nazari, S. Hadi,Forson, Kelton G.,Martinez, Erin E.,Hansen, Nicholas J.,Gassaway, Kyle J.,Lyons, Nathan M.,Kenney, Karissa C.,Valdivia-Berroeta, Gabriel A.,Smith, Stacey J.,Michaelis, David J.
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supporting information
p. 9589 - 9593
(2019/12/02)
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- Multifunctional Cyclopentadienes as a Scaffold for Combinatorial Bioorganometallics in [(η5-C5H2R1R2R3)M(CO)3] (M=Re, 99mTc) Piano-Stool Complexes
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Multifunctional cyclopentadiene (Cp) ligands and their rhenium and 99mTc complexes were prepared by a versatile synthetic route. The properties of these Cp ligands can be tuned on demand, either during their synthesis (variation of R1) or through post-synthetic functionalization with two equal or different vectors (V1 and V2). Variation of these groups enables a combinatorial approach in the synthesis of bioorganometallic complexes. This is demonstrated by the preparation of Cp ligands containing both electron-donating and electron-withdrawing groups at the R1 position and their subsequent homo- or heterofunctionalization with biovector models (benzylamine and phenylalanine) under standard amide bond-formation conditions. All ligands can be coordinated to the fac-[Re(CO)3]+ and fac-[99mTc(CO)3]+ cores to give tetrafunctional complexes in straightforward and functional-group-tolerant procedures. The 99mTc complexes were prepared in one step, in 30 min, and under aqueous conditions from generator-eluted [99mTcO4]?.
- Frei, Angelo,Spingler, Bernhard,Alberto, Roger
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supporting information
p. 10156 - 10164
(2018/07/29)
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- Copper-Catalyzed Enantio-, Diastereo-, and Regioselective [2,3]-Rearrangements of Iodonium Ylides
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The first highly enantioselective, diastereoselective, and regioselective [2,3]-rearrangement of iodonium ylides has been developed as a general solution to catalytic onium ylide rearrangements. In the presence of a chiral copper catalyst, substituted allylic iodides couple with α-diazoesters to generate metal-coordinated iodonium ylides, which undergo [2,3]-rearrangements with high selectivities (up to >95:5 r.r., up to >95:5 d.r., and up to 97 % ee). The enantioenriched iodoester products can be converted stereospecifically into a variety of onium ylide rearrangement products, as well as compounds that are not accessible by classical onium ylide rearrangements.
- Xu, Bin,Tambar, Uttam K.
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supporting information
p. 9868 - 9871
(2017/08/08)
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- Visible-Light Promoted Distereodivergent Intramolecular Oxyamidation of Alkenes
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The visible-light-promoted diastereodivergent intramolecular oxyamination of alkenes is described to construct oxazolindinones, pyrrolidinones and imidazolidones via mild generation of primary amidyl radicals from functionalized hydroxylamines. A unique phenomenon of highly diastereoselective ring-opening of aziridines controlled by electron sacrifices was observed. Highly diastereoselective amino alcohols derivatives were obtained efficiently through this protocol in gram scales. The mechanistic studies suggested the isolatable anti-aziridine intermediates were generated quickly from primary amidyl radicals and the diastereoselectivities were controlled by pKavalues of the electron sacrifices.
- Ren, Xiang,Guo, Qihang,Chen, Jianhui,Xie, Hujun,Xu, Qing,Lu, Zhan
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supporting information
p. 18695 - 18699
(2016/12/26)
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- Iron-catalyzed aerobic C-H functionalization of pyrrolones
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The aerobic oxidation of pyrrolones catalyzed by Fe(OTf)3 to form reactive N-acyliminium ion intermediates that undergo nucleophilic additions with alcohols to give the corresponding products in moderate to good yields is described.
- Liu, Li-Wei,Wang, Zhen-Zhen,Zhang, Hui-Hui,Wang, Wan-Shu,Zhang, Ji-Zong,Tang, Yu
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supporting information
p. 9531 - 9534
(2015/06/08)
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- Conformational Analysis, Thermal Rearrangement, and EI-MS Fragmentation Mechanism of (1(10)E,4E,6S,7R)-Germacradien-6-ol by 13C-Labeling Experiments
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An uncharacterized terpene cyclase from Streptomyces pratensis was identified as (+)-(1(10)E,4E,6S,7R)-germacradien-6-ol synthase. The enzyme product exists as two interconvertible conformers, resulting in complex NMR spectra. For the complete assignment of NMR data, all fifteen (13C1)FPP isotopomers (FPP=farnesyl diphosphate) and (13C15)FPP were synthesized and enzymatically converted. The products were analyzed using various NMR techniques, including 13C, 13C COSY experiments. The (13C)FPP isotopomers were also used to investigate the thermal rearrangement and EI fragmentation of the enzyme product. All 15 isotopomers of (13C1)- and fully labeled (13C15)farnesyl diphosphate were synthesized and converted to the title compound by a newly characterized bacterial terpene cyclase from Streptomyces pratensis. The enzyme products were used for structure elucidation of the sesquiterpene alcohol, full assignment of NMR data and a conformational analysis, and investigation of its Cope rearrangement and of its EI-MS fragmentation mechanism.
- Rabe, Patrick,Barra, Lena,Rinkel, Jan,Riclea, Ramona,Citron, Christian A.,Klapschinski, Tim A.,Janusko, Aron,Dickschat, Jeroen S.
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supporting information
p. 13448 - 13451
(2015/11/09)
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- Nickel-Catalyzed Regioselective Reductive Cross-Coupling of Aryl Halides with Polysubstituted Allyl Halides in the Presence of Imidazolium Salts
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The nickel-catalyzed direct reductive cross-coupling of aryl halides with readily accessible polysubstituted allyl halides provides an efficient method for preparing diverse allylated arenes under mild conditions. Both allyl bromides and allyl chlorides are compatible with the transformation.
- Zhang, Zhan,Xu, Lijun,Chen, Zhengkai,Liu, Zhubo,Miao, Maozhong,Song, Jinyu,Ren, Hongjun
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supporting information
p. 2784 - 2788
(2015/12/18)
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- Coupling reaction of magnesium alkylidene carbenoids with α-sulfonylallyllithiums: An efficient route to multi-substituted vinylallenes
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A variety of vinylallenes were successfully synthesized from 1-chlorovinyl p-tolyl sulfoxides and allyl or vinyl sulfones. Allyl and vinyl sulfones served as α-sulfonylallyllithium sources were prepared from carbonyl compounds in three or four steps in good overall yields. The coupling reaction of α-sulfonylallyllithiums with magnesium alkylidene carbenoids, which were generated from 1-chlorovinyl p-tolyl sulfoxides and isopropylmagnesium chloride, afforded multi-substituted vinylallenes in up to 88% yield. Georg Thieme Verlag KG Stuttgart · New York.
- Kimura, Tsutomu,Kobayashi, Gen,Ishigaki, Masashi,Inumaru, Mio,Sakurada, Jo,Satoh, Tsuyoshi
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p. 3623 - 3632
(2013/02/23)
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- METHOD OF RAPID METHYLATION, KIT FOR PREPARING PET TRACER AND METHOD OF PRODUCING PET TRACER
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It is intended to provide a method of rapid methylation of an aromatic compound or an alkenyl compound, which is capable of obtaining an aromatic compound or an alkenyl compound labeled with a methyl group or a fluoromethyl group under a mild condition rapidly in high yield using an organic boron compound whose toxicity is not so high as a substrate; a kit for preparing a PET tracer to be used in the same, and a method of producing a PET tracer using the same. In an aprotic polar solvent, methyl iodide or X-CH2F (wherein X is a functional group which can be easily released as an anion), an organic boron compound in which an aromatic ring or an alkenyl group is attached to boron are subjected to cross-coupling in the presence of a palladium(0) complex, a phosphine ligand, and a base.
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Page/Page column 10
(2009/07/10)
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- Palladium(0)-mediated rapid methylation and fluoromethylation on carbon frameworks by reacting methyl and fluoromethyl iodide with aryl and alkenyl boronic acid esters: Useful for the synthesis of [11C]CH 3-C-and [18F]FCH2-C-containing PET tracers (PET = positron emission tomography)
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The rapid methylation and fluoromethylation on aryl and alkenyl carbon frameworks by reacting methyl and fluoromethyl iodide with aryl and alkenyl boronates have been studied with the focus on the realization of the synthesis of [11C]CH3- and [18F]FCH2-labeled positron emission tomography (PET) tracers. The coupling of methyl iodide and pinacol phenylboronate (40 equiv) is accomplished in > 91% yield within 5 min at 60 °C under the conditions of [Pd2(dba)3]/P(o- CH3C6H4)3/K2CO 3 (0.5:2:2; dba = di-benzylideneacetone) in DMF. The reaction shows a high generality and is applicable to various types of aryl and alkenyl boronates, giving the corresponding methylated derivatives in high yields (80-99). This reaction is also useful for the rapid incorporation of the fluoromethyl group. Thus, this boron protocol provides a firm chemical basis for the synthesis of 11C- and 18F-incorporated PET tracers and can be used as a complementary method for [11C]methylation together with our previous and ongoing processes using organotributylstannanes.
- Doi, Hisashi,Ban, Ikuya,Nonoyama, Akihito,Sumi, Kengo,Kuang, Chunxiang,Hosoya, Takamitsu,Tsukada, Hideo,Suzuki, Masaaki
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experimental part
p. 4165 - 4171
(2009/12/01)
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- Exploration of the molecular origin of the azinomycin epoxide: Timing of the biosynthesis revealed
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(Equation Presented) Streptomyces sahachiroi whole cell feeding experiments, utilizing putative precursors labeled with stable isotopes, established that the epoxide unit of the DNA cross-linked agents, azinomycin A and B, proceeds via a valine-dependent pathway and that hydroxylation and dehydration precedes formation of the terminal epoxide. Sodium 3-methyl-2-oxobutenoate, formed through a transimination reaction, was shown to be the penultimate precursor incorporated into the azinomycin epoxide.
- Sharma, Vasudha,Kelly, Gilbert T.,Watanabe, Coran M. H.
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supporting information; experimental part
p. 4815 - 4818
(2009/05/31)
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- Rh-catalyzed formation of dioxolanes from α-alkyl diazoesters: Diastereoselective cycloadditions of carbonyl ylides with selectivity over β-hydride elimination
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(Chemical Equation Presented) Described here is a diastereoselective Rh-catalyzed method for the preparation of dioxolanes from α-alkyl- α-diazoesters. This represents the first general method for generating carbonyl ylides from α-diazoesters that possess β-hydrogens, as such diazo compounds typically give rise to alkenes via β-hydride elimination. Subsequent cycloaddition with aromatic aldehydes gives tetrasubstituted dioxolanes with unusually high diastereoselectivity. A model is set forth to explain the diastereoselectivity of the cycloaddition.
- DeAngelis, Andrew,Panne, Patricia,Yap, Glenn P. A.,Fox, Joseph M.
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p. 1435 - 1439
(2008/09/17)
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- Discovery and preclinical profile of saxagliptin (BMS-477118): A highly potent, long-acting, orally active dipeptidyl peptidase IV inhibitor for the treatment of type 2 diabetes
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Efforts to further elucidate structure-activity relationships (SAR) within our previously disclosed series of β-quaternary amino acid linked L-cis-4,5-methanoprolinenitrile dipeptidyl peptidase IV (DPP-IV) inhibitors led to the investigation of vinyl substitution at the β-position of α-cycloalkyl-substituted glycines. Despite poor systemic exposure, vinyl-substituted compounds showed extended duration of action in acute rat ex vivo plasma DPP-IV inhibition models. Oxygenated putative metabolites were prepared and were shown to exhibit the potency and extended duration of action of their precursors in efficacy models measuring glucose clearance in Zuckerfa/fa rats. Extension of this approach to adamantylglycine- derived inhibitors led to the discovery of highly potent inhibitors, including hydroxyadamantyl compound BMS-477118 (saxagliptin), a highly efficacious, stable, and long-acting DPP-IV inhibitor, which is currently undergoing clinical trials for treatment of type 2 diabetes.
- Augeri, David J.,Robl, Jeffrey A.,Betebenner, David A.,Magnin, David R.,Khanna, Ashish,Robertson, James G.,Wang, Aiying,Simpkins, Ligaya M.,Taunk, Prakash,Huang, Qi,Han, Song-Ping,Abboa-Offei, Benoni,Cap, Michael,Xin, Li,Tao, Li,Tozzo, Effie,Welzel, Gustav E.,Egan, Donald M.,Marcinkeviciene, Jovita,Chang, Shu Y.,Biller, Scott A.,Kirby, Mark S.,Parker, Rex A.,Hamann, Lawrence G.
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p. 5025 - 5037
(2007/10/03)
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- Exo Selective Enantioselective Nitrone Cycloadditions
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We have developed a novel method for accessing exo adducts with high enantioselectivity in nitrone cycloadditions to enoates. Pyrazolidinones proved to be effective achiral templates in the cycloadditions, providing exo adducts typically in >15:1 selectivity and 90-98% ee. The use of Lewis acids that form square planar complexes, such as copper triflate, was important for obtaining high exo selectivity. Copyright
- Sibi, Mukund P.,Ma, Zhihua,Jasperse, Craig P.
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p. 718 - 719
(2007/10/03)
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- Preparation of [1,2,3,4,5-13C 5]-5-Amino-4-oxopentanoic Acid (ALA) - Design of a Synthetic Scheme to Prepare Any 13C- and 15N-Isotopomer with High Isotopic Enrichment
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5-Amino-4-oxopentanoic acid (5-aminolevulinic acid) is a precursor in the biosynthesis of the biologically active porphyrins such as chlorophyll, bacteriochlorophyll, heme, etc. These systems are central in photosynthesis, oxygen transport, electron transport, etc. In this paper we describe a simple scheme to prepare any isotopomer of 5-aminolevulinic acid in a few steps in high yield. Using a similar scheme, levulinic acid can now also be prepared in any isotopomeric form. Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003.
- Shrestha-Dawadi, Prativa Bade,Lugtenburg, Johan
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p. 4654 - 4663
(2007/10/03)
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- Aglairubine - Discrepancies during the course of structure elucidation
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A short synthesis of the originally proposed structure 1 for the putrescine alkaloid aglairubine is presented as well as for a conceivable structure alternative 11. Due to the ascertained mismatch of spectroscopical data for synthetic and natural compounds, the published aglairubine structure has to be revised.
- Detterbeck, Richard,Hesse, Manfred
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p. 4609 - 4612
(2007/10/03)
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- Kinetics of alcoholysis of β,β-dimethylacryloyl chloride
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Rate constants and activation parameters have been determined for alcoholysis of β,β-dimethylacryloyl chloride with 14 alcohols in benzene at a reactant ratio of 1:1. The reaction proceeds via formation of H-complex or charge-transfer complex. Appropriate description of the effect of alcohol on the reaction rate requires simultaneous application of the Hammett-Taft and Koppel'-Pal'm equations.
- Marshalok,Oglashennyi,Makitra,Pirig,Yatchishin
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p. 1410 - 1418
(2007/10/03)
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- An efficient use of zeolite catalysts for esterification of carboxylic acids
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A mild and practical method (batch process) for the esterification of carboxylic acids with alcohols using zeolite catalysts in good to excellent yields is described. The esterification of phenylacetic acid with ethanol has also been carried out in very high yield using continuous flow fixed bed reactor.
- Gumaste, Vikas K.,Deshmukh,Bhawal
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p. 1174 - 1179
(2007/10/03)
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- Studies of the use of elemento-organic compounds of the fifteenth and sixteenth groups in organic synthesis LXXI. Reaction of α-halogeno carboxylic derivatives with carbonyl compounds promoted by tributylstibine
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α,β-Unsaturated esters and amides were conveniently obtained from the trialkylstibine-promoted reaction of α-halogenocarboxylic derivatives with carbonyl compounds.In this reaction, a quaternary stibonium salt is an active intermediate that can be trapped and can undergo further reaction with the substrate.
- Huang, Yao-Zeng,Chen, Chen,Shen, Yanchang
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- Palladium-Catalyzed, Atmospheric Pressure Ethoxycarbonylation of Allylic Halides under the Influence of Sodium Ethoxide. A Facile Synthesis of β,γ-Unsaturated Esters
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Atmospheric pressure ethoxycarbonylation of allylic halides is realized under the influence of sodium ethoxide.This reaction is catalyzed by Na2PdCl4-bis(diphenylphosphino)ethane (dppe) and offers a convenient synthetic method to β,γ-unsaturated esters.
- Kiji, Jitsuo,Okano, Tamon,Konishi, Hisatoshi,Nishiumi, Wataru
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p. 1873 - 1876
(2007/10/02)
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- COPPER ION-PROMOTED ESTERIFICATIONS
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Esters are made from carboxylic acids on heating with an alkohol in the presence of a copper salt at 130 deg.
- Ho, Tse-lok
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p. 2897 - 2898
(2007/10/02)
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- New One-Pot Preparation of α,β-Unsaturated Carboxylic Acid Esters from Carbonyl Compounds
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A series of α,β-unsaturated carboxylic acid esters have been prepared by the reaction of carbonyl compounds with alkoxy acetylide anions generated in situ from the readily available α-chloroacetaldehyde dialkyl acetals in the presence of lithium diisopropylamide, followed by aqueous acidic work-up.
- Olah, George A.,Wu, An-hsiang,Farooq, Omar,Prakash, G. K. Surya
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p. 537 - 538
(2007/10/02)
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- THE APPLICATION OF HIGH PRESSURE TO SOME DIFFICULT WITTIG REACTIONS
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Wittig reactions, previously shown to be favourably accelerated under pressure have been carried out between the stabilized ylides carboethoxymethylenetriphenylphosphorane and carboethoxyethylidinetriphenylphosphorane with a variety of ketones at 9-10 kbar pressure.Succesful formation of tri- and tetra-substituted ethylenes are reported.
- Isaacs, Neil S.,El-Din, Ghazi Najim
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p. 2191 - 2192
(2007/10/02)
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- Factors Affecting the Absorption Maxima of Polyene Iminium Systems: A Model Study for Rhodopsin and Bacteriorhodopsin
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We had proposed external point-charge models to explain the variance in absorption maxima of cattle rhodopsin and the purple color of bacteriorhodopsin.In the former visual pigment model, a negative counteranion resides ca. 3 Angstroem from the protonated Schiff base (SBH+) linkage and another point charge is located ca. 3 Angstroem from C-12 and C-14 of the 11-cis-retinal chromophore (Figure 1a).In the bacteriorhodopsin model (Figure 1c) a negative counteranion is located ca. 3 Angstroem from SBH+ and another point charge is present near the ionone ring.A total of 15 nonsteroidal and steroidal di-, tetra-, and hexaene iminium compounds with and without COOH/COO- groups near the polyene chain have been synthesized in order to structurally mimic the charge distributions within the binding sites of the two pigments.The electronic spectra of these polyene iminium compounds have been measured in different solvents with and without addition of base.The results show that the interplay of the following three factors determines the absorption maxima of these compounds, i.e., the additional negative charge, the distance between the iminium nitrogen and its counteranion, and the solvent polarity.In the case of the natural pigments, the evidence obtained so far shows that the external point charges are important spectroscopic determinants.
- Sheves, Mordechai,Nakanishi, Koji
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p. 4033 - 4039
(2007/10/02)
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- The Synthesis of 5-Hydroxy-2,4-dimethyl-1-hexene-1,5-dicarboxylic Acid (Nemorensic Acid)
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The synthesis of nemorensic acid in the open-chain form, i.e. of 5-hydroxy-2,4-dimethyl-1-hexene-1,5-dicarboxylic acid is described.
- Roeder, Erhard,Wiedenfeld, Helmut,Frisse, Manfred
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p. 803 - 806
(2007/10/02)
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