- Development of an enolate alkynylation approach towards the synthesis of the taiwanschirin natural products
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Through the use of model studies, an approach was conceived towards the synthesis of the taiwanschirin family of natural products. These are structurally complex compounds which represent highly challenging and biologically active targets for total synthesis. This work describes a successful synthesis of the complex taiwanschirin fused [8,6,5] core through a novel alkynylation reaction coupled with an intramolecular Heck reaction used to construct the 8-membered ring.
- Christensen, Kirsten E.,Donohoe, Timothy J.,Haughey, Maxwell B.,Poole, Darren L.
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p. 13392 - 13397
(2021/11/01)
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- Mild and Regioselective Bromination of Phenols with TMSBr
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In this work, an unexpected promoting effect of by-product thioether was observed, leading to a mild and regioselective bromination of phenols with TMSBr. This method can tolerate a series of functional groups such as the reactive methoxyl, amide, fluoro, chloro, bromo, aldehyde, ketone and ester groups, and has the potential to recycle the by-product thioether and isolate the desired product under column chromatography-free conditions. Mechanism studies revealed that O–H···S hydrogen bond may be formed between phenol and by-product thioether. Possibly owing to the steric hindrance effect from by-product thioether, the electrophilic bromination at para-position of phenols is much favorable.
- Ma, Xiantao,Yu, Jing,Jiang, Mengyuan,Wang, Mengyu,Tang, Lin,Wei, Mengmeng,Zhou, Qiuju
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supporting information
p. 4593 - 4596
(2019/07/05)
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- Co-immobilization of Laccase and TEMPO in the Compartments of Mesoporous Silica for a Green and One-Pot Cascade Synthesis of Coumarins by Knoevenagel Condensation
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Co-immobilization of bio- and chemocatalysts produces sustainable, recyclable hybrid systems that open new horizons for green cascade approaches in organic synthesis. Here, the co-immobilization of laccase and 2,2,6,6-tetramethylpiperidin-1-oxyl (TEMPO) in mesoporous silica was used for the one-pot aqueous synthesis of 30 coumarin-3-carboxylate derivatives under mild conditions through the condensation of in situ oxidized 2-hydroxybenzyl alcohols and malonate derivatives. A maximum yield was obtained after incubating at pH 6.0 and 45 °C for 24 h. An efficient organic synthesis was catalyzed by the hybrid catalyst in 10 % organic solvent. More than 95 % of the initial activity of the enzyme was preserved after 10 cycles, and no significant catalyst deactivation occurred after 10 runs. This new system efficiently catalyzed the in situ aerobic oxidation of salicyl alcohols, followed by Knoevenagel condensation, which confirmed the possibility of producing efficient hybrid catalysts by co-immobilization of catalytic species in mesoporous materials.
- Mogharabi-Manzari, Mehdi,Amini, Mohsen,Abdollahi, Mohammad,Khoobi, Mehdi,Bagherzadeh, Ghodsieh,Faramarzi, Mohammad Ali
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p. 1542 - 1546
(2018/02/28)
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- Pd-Catalyzed Ortho C-H Hydroxylation of Benzaldehydes Using a Transient Directing Group
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The direct Pd-catalyzed ortho C-H hydroxylation of benzaldehydes was achieved using 4-chloroanthranilic acid as the transient directing group, 1-fluoro-2,4,6-trimethylpyridnium triflate as the bystanding oxidant, and p-toluenesulfonic acid as the putative oxygen nucleophile. The unusual C-H chlorination and polyfluoroalkoxylation reactions signaled the importance of external nucleophiles to the outcome of Pd(IV) reductive eliminations.
- Chen, Xiao-Yang,Ozturk, Seyma,Sorensen, Erik J.
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supporting information
p. 6280 - 6283
(2017/12/08)
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- (Z)-selective Takai olefination of salicylaldehydes
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The Takai olefination (or Takai reaction) is a method for the conversion of aldehydes to vinyl iodides, and has seen widespread implementation in organic synthesis. The reaction is usually noted for its high (E)-selectivity; however, herein we report the
- Geddis, Stephen M.,Hagerman, Caroline E.,Galloway, Warren R. J. D.,Sore, Hannah F.,Goodman, Jonathan M.,Spring, David R.
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supporting information
p. 323 - 328
(2017/03/14)
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- Aldehyde-Assisted Ruthenium(II)-Catalyzed C-H Oxygenations
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Versatile ruthenium(II) complexes allow for site-selective C-H oxygenations with weakly-coordinating aldehydes. The challenging C-H functionalizations proceed with high chemoselectivity by rate-determining C-H metalation. The new method features an ample substrate scope, which sets the stage for the step-economical preparation of various bioactive heterocycles.
- Yang, Fanzhi,Rauch, Karsten,Kettelhoit, Katharina,Ackermann, Lutz
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supporting information
p. 11285 - 11288
(2016/02/18)
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- PROCESS FOR PRODUCTION OF OXIDATION REACTION PRODUCT OF AROMATIC COMPOUND
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The present invention provides a process for producing an oxidation reaction product of an aromatic compound, having excellent environmental load reduction performance, cost reduction performance, etc. Provided is a process for producing an oxidation reaction product of a raw material aromatic compound by reacting the raw material aromatic compound with an oxidizing agent. The process further uses an electron donor-acceptor linked molecule. The process includes the step of: reacting the electron donor-acceptor linked molecule in an electron-transfer state, the oxidizing agent, and the raw material aromatic compound, thereby generating an oxidation reaction product resulting from oxidation of the raw material aromatic compound.
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Page/Page column 20
(2012/07/14)
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- A macrocyclic approach to tetracycline natural products. Investigation of transannular alkylations and Michael additions
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A new approach to the tetracycline core structure is presented. The pivotal intermediate is identified as macrocycle III. The two interior bonds (C4a-C12a and C5a-C11a) are to be constructed through sequential transannular Michael additions (III-II) and compression-promoted transannular isoxazole alkylations from intermediate II.
- Wzorek, Joseph S.,Kn?pfel, Thomas F.,Sapountzis, Ioannis,Evans, David A.
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supporting information
p. 5840 - 5843
(2013/02/25)
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- TRICYCLIC HETEROCYCLIC DERIVATIVES
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The present invention relates to a tricyclic heterocyclic derivative of Formula (I) wherein the variables are as defined in the specification. The present invention further relates to pharmaceutical compositions comprising these compounds and to their use in therapy, in particular for the treatment of serotonin-mediated disorders such as obesity, schizophrenia and cognitive dysfunction.
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Page/Page column 134-135
(2009/04/25)
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- Chromene chromium carbene complexes in the syntheses of naphthopyran and naphthopyrandione units present in photochromic materials and biologically active natural products
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The carbene complex 5-(2,2-dimethyl-2H-chromene)methoxylmethylene chromium pentacarbonyl will undergo a benzannulation reaction with phenylacetylene, 1-pentyne, 3-hexyne, and trimethylsilylacetylene to give 7-hydroxy-10-methoxy- 3H-naphtho[2.1-b]pyrans as
- Rawat, Manish,Prutyanov, Victor,Wulff, William D.
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p. 11044 - 11053
(2007/10/03)
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- Synthesis of regiospecifically substituted 2-hydroxybenzocyclobutenones
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Regiospecifically substituted 2-hydroxybenzocyclobutenones were synthesized from the corresponding TBS protected 2-bromo-mandelate esters via halogen-metal exchange, cyclization, and subsequent deprotection.
- Lear, Yvonne,Durst, Tony
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p. 817 - 824
(2007/10/03)
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- Binding of Phenylalkylamine Derivatives at 5-HT1C and 5-HT2 Serotonin Receptors: Evidence for a Lack of Selectivity
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Certain phenyalkylamine derivatives have been considered to bind selectively at 5-HT2 serotonin receptors.It is now recognized that the most widely used derivatives, i.e., 1-(2,5-dimethoxy-4-X-phenyl)-2-aminopropanes where X = Me (DOM), Br (DOB), and I (DOI) (1-3, respectively) also bind at the more recently identified population of serotonin 5-HT1C receptors.The purpose of the present investigation was to determine whether simple phenylalkylamines bind selectively at one population of receptors over the other.An examination of 34 derivatives reveals (i) similar structure-affinity relationships and (ii) a significant correlation (r = >0.9, n = 25) between 5-HT1C and 5-HT2 affinity.None of the compounds included in the present study displayed more than a 10-fold selectivity for one population of these receptors over the other; the results suggest that these compounds (including the widely used 5-HT2 agonists DOB and DOI) are 5-HT1C/5-HT2 agents.
- Glennon, Richard A.,Raghupathi, Reva,Bartyzel, Piotr,Teitler, Milt,Leonhardt, Sigrun
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p. 734 - 740
(2007/10/02)
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