Category: 617-55-0

Zhang, Junjie; Wang, Huanxia; Ma, Yun; Wang, Youming; Zhou, Zhenghong; Tang, Chuchi published the artcile< CaF2 catalyzed SN2 type chlorodehydroxylation of chiral secondary alcohols with thionyl chloride: a practical and convenient approach for the preparation of optically active chloroalkanes>, Category: esters-buliding-blocks, the main research area is chloroalkane chiral preparation; calcium fluoride catalyst chlorodehydroxylation chiral secondary alc thionyl chloride.

A CaF2 catalyzed chlorodehydroxylation of chiral secondary alcs. with thionyl chloride has been developed. The chlorination reaction is effective for a wide range of alcs., generating the corresponding chloroalkanes in good yield with high optical purity with inversion of the original configuration of the alc.

Tetrahedron Letters published new progress about Chlorination. 617-55-0 belongs to class esters-buliding-blocks, and the molecular formula is C6H10O5, Category: esters-buliding-blocks.

Referemce:
Ester – Wikipedia,
Ester – an overview | ScienceDirect Topics

Dinca, Emanuela; Hartmann, Philip; Smrcek, Jakub; Dix, Ina; Jones, Peter G.; Jahn, Ullrich published the artcile< General and Efficient α-Oxygenation of Carbonyl Compounds by TEMPO Induced by Single-Electron-Transfer Oxidation of Their Enolates>, Formula: C6H10O5, the main research area is alpha oxygenated carbonyl compound preparation; regioselective oxygenation carbonyl compound single electron transfer oxidation; stable free radical TEMPO coupling carbonyl compound; piperidinyloxy ketone ester amide acid nitrile preparation; enolate aggregate influence oxygenation reactions significantly; chemoselective reduction piperidinyloxy compound; hydroxy alpha carbonyl compound preparation; monoprotected diol preparation; amino alc protected preparation.

A generally applicable method for the synthesis of protected α-oxygenated carbonyl compounds is reported. It is based on the single-electron-transfer oxidation of easily generated enolates to the corresponding α-carbonyl radicals. Coupling with the stable free radical TEMPO provides α-(piperidinyloxy) ketones, esters, amides, acids or nitriles in moderate-to-excellent yields. Enolate aggregates influence the outcome of the oxygenation reactions significantly. Competitive reactions have been analyzed and conditions for their minimization are presented. Chemoselective reduction of the products led to either N-O bond cleavage to α-hydroxy carbonyl compounds or reduction of the carbonyl functionality to monoprotected 1,2-diols or O-protected amino alcs.

European Journal of Organic Chemistry published new progress about Aldehydes Role: RCT (Reactant), RACT (Reactant or Reagent) (enolization and TEMPO-induced single-electron-transfer oxidation of). 617-55-0 belongs to class esters-buliding-blocks, and the molecular formula is C6H10O5, Formula: C6H10O5.

Referemce:
Ester – Wikipedia,
Ester – an overview | ScienceDirect Topics

Listowsky, Irving; Avigad, Gad; Englard, Sasha published the artcile< Conformational equilibria and stereochemical relations among carboxylic acids>, HPLC of Formula: 617-55-0, the main research area is acyclic acid conformation; conformation acyclic acid; circular dichroism acyclic acid.

The CO spectra of certain acyclic carboxylic acids were surveyed in an effort to study their conformation in solution In aqueous solution the spectra of many α-hydroxy acids were characterized by two overlapping ellipticity bands; a weak one in the 240-mμ spectral region and a more intense one of opposite sign near 210 mμ. At elevated temperatures or in solvents of low dielec. constant, the band of longer wavelength increased in intensity with an attendant decrease in the short-wavelength band. These properties are compatible with the presence of two structural species in equilibrium, and could be related to the contributions of specific rotational isomers of the acids. Conformations with the hydroxyl and carbonyl groups in an eclipsed alignment are designated as preferred. In contrast to the α-hydroxy acids, carboxylic acids with α-alkyl substituents generally showed only a single dichroic band centered near 210 mμ. In general, coplanarity of the carboxyl group and α-substituents was assumed, and interpretations in terms of the preferred orientation of substituents adjacent to the carboxyl group are suggested. The proposed population of rotational isomers was consistent with the observed effects of solvent polarity, temperature, polarity of substituents, and predicted steric interactions. An empirical rule relating the sign of ellipticity and the conformation of these classes of carboxylic acids was applied.

Journal of Organic Chemistry published new progress about Acids Role: PRP (Properties). 617-55-0 belongs to class esters-buliding-blocks, and the molecular formula is C6H10O5, HPLC of Formula: 617-55-0.

Referemce:
Ester – Wikipedia,
Ester – an overview | ScienceDirect Topics

Muraoka, Osamu; Toyooka, Naoki; Ohshima, Yumiko; Narita, Norihiko; Momose, Takefumi published the artcile< Synthesis of natural (S)-(-)-tulipalin B starting from L-malic acid as a chiral pool>, Recommanded Product: (S)-Dimethyl 2-hydroxysuccinate, the main research area is tulipalin B total synthesis enantioselectivity; malic acid chiral synthon tulipalin B.

Naturally occurring tulipalin B (I) was prepared enantioselectively from chiral synthon L-malic acid (II) in 15% yield.

Heterocycles published new progress about Chiral synthons. 617-55-0 belongs to class esters-buliding-blocks, and the molecular formula is C6H10O5, Recommanded Product: (S)-Dimethyl 2-hydroxysuccinate.

Referemce:
Ester – Wikipedia,
Ester – an overview | ScienceDirect Topics

Pommier, Agnes; Pons, Jean-Marc; Kocienski, Philip J. published the artcile< The First Total Synthesis of (-)-Lipstatin>, Electric Literature of 617-55-0, the main research area is asym synthesis lipstatin; stereoselective cycloaddition silylketene tetradecadienal.

A key step in the first total synthesis of the potent pancreatic lipase inhibitor (-)-lipstatin (I) is a diastereoselective Lewis acid-promoted [2 + 2] cycloaddition reaction between (trimethylsilyl)ketene Me(CH2)5C(SiMe3):CO and tetradecadienal II (TBS = Me3CSiMe2), which is prepared from di-Me (S)-(-)-malate.

Journal of Organic Chemistry published new progress about [2+2] Cycloaddition reaction. 617-55-0 belongs to class esters-buliding-blocks, and the molecular formula is C6H10O5, Electric Literature of 617-55-0.

Referemce:
Ester – Wikipedia,
Ester – an overview | ScienceDirect Topics

Nagano, Masanobu; Tanaka, Masakazu; Doi, Mitsunobu; Demizu, Yosuke; Kurihara, Masaaki; Suemune, Hiroshi published the artcile< Helical-Screw Directions of Diastereoisomeric Cyclic α-Amino Acid Oligomers>, HPLC of Formula: 617-55-0, the main research area is oligomer cyclic amino acid diastereomer preparation helical secondary structure.

Two series of homooligomers composed of diastereoisomeric cyclic α-amino acids having two chiral centers at the α-carbon and the side chain were synthesized, and their preferred secondary structures were studied in solution and in the crystal state. The oligomers are a new class of helical-foldamers possessing two kinds of chiral centers on the helical backbone and at the lateral surface of the helix.

Organic Letters published new progress about Crystal structure. 617-55-0 belongs to class esters-buliding-blocks, and the molecular formula is C6H10O5, HPLC of Formula: 617-55-0.

Referemce:
Ester – Wikipedia,
Ester – an overview | ScienceDirect Topics

Aponick, Aaron; Li, Chuan-Ying; Palmes, Jean A. published the artcile< Au-Catalyzed cyclization of monopropargylic triols: an expedient synthesis of monounsaturated spiroketals>, Computed Properties of 617-55-0, the main research area is spiroketal derivative preparation; monopropargylic triol preparation cyclization gold; gold cyclization catalyst.

The gold-catalyzed cyclization of monopropargylic triols to form olefin-containing spiroketals is reported. The reactions are rapid and high yielding when 2 mol % of the catalyst generated in situ from Au[P(t-Bu)2(o-biphenyl)]Cl and AgOTf is employed in THF at 0 °C. A range of differentially substituted triols leading to substituted 5- and 6-membered ring spiroketals were prepared and function well in the reaction.

Organic Letters published new progress about Cyclization. 617-55-0 belongs to class esters-buliding-blocks, and the molecular formula is C6H10O5, Computed Properties of 617-55-0.

Referemce:
Ester – Wikipedia,
Ester – an overview | ScienceDirect Topics

Clark, J. Stephen; Fessard, Thomas C.; Wilson, Claire published the artcile< A Concise and Stereoselective Synthesis of the A-Ring Fragment of the Gambieric Acids>, Formula: C6H10O5, the main research area is asym synthesis gambieric acid ring fragment rearrangement oxonium ylide.

The A-ring fragment I of the gambieric acids has been prepared by a short and efficient route. The key 3(2H)-furanone intermediate has been obtained by [2,3] rearrangement of an allylic oxonium ylide generated from intramol. reaction of a crotyl ether with a copper carbenoid. A single stereogenic center has been set by using a chiral pool starting material and the other three have been established by using highly diastereoselective substrate-controlled transformations.

Organic Letters published new progress about Rearrangement ([2,3]-rearrangement). 617-55-0 belongs to class esters-buliding-blocks, and the molecular formula is C6H10O5, Formula: C6H10O5.

Referemce:
Ester – Wikipedia,
Ester – an overview | ScienceDirect Topics

Sartori, G.; Maggi, R. published the artcile< Carboxylic acid esters: product subclass 16: 3-heteroatom-substituted alkanoic acid esters>, COA of Formula: C6H10O5, the main research area is review heteroatom substituted alkanoic acid ester preparation organic synthesis; beta heteroatom substituted carboxylic acid ester preparation review.

A review of methods to prepare 3-heteroatom-substituted alkanoic acid esters.

Science of Synthesis published new progress about Carboxylic esters Role: SPN (Synthetic Preparation), PREP (Preparation) (β-heteroatom-substituted). 617-55-0 belongs to class esters-buliding-blocks, and the molecular formula is C6H10O5, COA of Formula: C6H10O5.

Referemce:
Ester – Wikipedia,
Ester – an overview | ScienceDirect Topics

Prasanth, C. P.; Joseph, Ebbin; Abhijith, A.; Nair, D. S.; Ibnusaud, Ibrahim; Raskatov, Jevgenij; Singaram, Bakthan published the artcile< Stabilization of NaBH4 in Methanol Using a Catalytic Amount of NaOMe. Reduction of Esters and Lactones at Room Temperature without Solvent-Induced Loss of Hydride>, COA of Formula: C6H10O5, the main research area is sodium borohydride methanol catalysis reduction ester lactone.

Rapid reaction of NaBH4 with MeOH precludes its use as a solvent for large-scale ester reductions We have now learned that a catalytic amount of NaOMe (5 mol %) stabilizes NaBH4 solutions in methanol at 25 °C and permits the use of these solutions for the reduction of esters to alcs. The generality of this reduction method was demonstrated using 22 esters including esters of naturally occurring chiral γ-butyrolactone containing dicarboxylic acids. This method permits the chemoselective reductions of esters in the presence of cyano and nitro groups and the reductive cyclization of a pyrrolidinedione ester to a fused five-membered furo[2,3-b]pyrrole and a (-)-crispine A analog in high optical and chem. yields. Lactones, aliphatic esters, aromatic esters containing electron-withdrawing groups, and heteroaryl esters are reduced more rapidly than aryl esters containing electron-donating groups. The 11B NMR spectrum of the NaOMe-stabilized NaBH4 solutions showed a minor quartet due to monomethoxyborohydride (NaBH3OMe) that persisted up to 18 h at 25 °C. We postulate that NaBH3OMe is probably the active reducing agent. In support of this hypothesis, the activation barrier for hydride transfer from BH3(OMe)- onto benzoic acid Me ester was calculated as 18.3 kcal/mol.

Journal of Organic Chemistry published new progress about Aliphatic esters Role: RCT (Reactant), RACT (Reactant or Reagent). 617-55-0 belongs to class esters-buliding-blocks, and the molecular formula is C6H10O5, COA of Formula: C6H10O5.

Referemce:
Ester – Wikipedia,
Ester – an overview | ScienceDirect Topics