Month: October 2022

Tietze, Lutz F.; Hungerland, Tim; Duefert, Alexander; Objartel, Ina; Stalke, Dietmar published the artcile< Synthesis of tetrasubstituted alkenes through a palladium-catalyzed domino carbopalladation/C-H-activation reaction>, Name: 2-Bromo-4-(trifluoromethyl)phenol, the main research area is helical tetrasubstituted alkene preparation; propargylic alc preparation domino carbopalladation bond activation.

Helical tetrasubstituted alkenes, e.g., I, were obtained in a highly efficient way through a palladium-catalyzed domino-carbopalladation/C-H-activation reaction of propargylic alcs., e.g., II, in good to excellent yields. Electron-withdrawing- and electron-donating substituents can be introduced onto the upper and lower aromatic rings. The substrates for the domino process were synthesized by addition of the lithiated alkyne to various aldehydes; moreover, the substrates were accessible enantioselectively (in 95 % ee) by reduction of the corresponding ketone using the Noyori procedure.

Chemistry – A European Journal published new progress about Alcohols, propargyl Role: RCT (Reactant), SPN (Synthetic Preparation), RACT (Reactant or Reagent), PREP (Preparation). 81107-97-3 belongs to class bromides-buliding-blocks, and the molecular formula is C7H4BrF3O, Name: 2-Bromo-4-(trifluoromethyl)phenol.

Referemce:
Bromide – Wikipedia,
bromide – Wiktionary

Peng, Pan; Yan, Xingxiu; Zhang, Ke; Liu, Zhao; Zeng, Li; Chen, Yixuan; Zhang, Heng; Lei, Aiwen published the artcile< Electrochemical C-C bond cleavage of cyclopropanes towards the synthesis of 1,3-difunctionalized molecules>, Application of C7H7BrO2S, the main research area is aryl fluoropropane regioselective chemoselective preparation; aromatic cyclopropane triethylamine trihydrofluoride electrochem bond cleavage fluorination; alc aryl cyclopropane electrochem bond cleavage oxyfluorination; ether aryl cyclopropane electrochem bond cleavage oxyfluorination; methanol aryl cyclopropane electrochem bond cleavage dioxygenation.

An electrochem. C-C bond cleavage and 1,3-difuntionalization of arylcyclopropanes under catalyst-free and external-oxidant-free conditions. It involved 1,3-difluorination, 1,3-oxyfluorination and 1,3-dioxygenation of arylcyclopropanes with a high chemo- and regioselectivity by the strategic choice of nucleophiles. This protocol has good functional groups tolerance and can be scaled up. Mechanistic studies demonstrated that arylcyclopropane radical cation obtained from the anode oxidation and the subsequently generated benzyl carbonium were the key intermediates in this transformation. This development provided a scenario for constructing 1,3-difunctionalized mols.

Nature Communications published new progress about Aryl bromides Role: RCT (Reactant), RACT (Reactant or Reagent). 5751-83-7 belongs to class bromides-buliding-blocks, and the molecular formula is C7H7BrO2S, Application of C7H7BrO2S.

Referemce:
Bromide – Wikipedia,
bromide – Wiktionary

He, Zhi-Tao; Zhao, Yi-Shuang; Tian, Ping; Wang, Chuan-Chuan; Dong, Han-Qing; Lin, Guo-Qiang published the artcile< Copper-Catalyzed Asymmetric Hydroboration of α-Dehydroamino Acid Derivatives: Facile Synthesis of Chiral β-Hydroxy-α-amino Acids>, Category: bromides-buliding-blocks, the main research area is dehydroamino acid preparation asym hydroboration copper catalyst; hydroxy amino acid asym preparation.

The Cu-catalyzed asym. conjugate hydroboration reaction of β-substituted α-dehydroamino acid derivatives has been established, affording enantio-enriched syn- and anti-β-boronate-α-amino acid derivatives with excellent combined yields (83-99%, dr ≈ 1:1) and excellent enantioselectivities (92-98% ee). The hydroboration products were expediently converted into valuable β-hydroxy-α-amino acid derivatives, which were widely used in the preparation of chiral drugs and bioactive mols.

Organic Letters published new progress about Amino acids, hydroxy Role: SPN (Synthetic Preparation), PREP (Preparation). 188813-04-9 belongs to class bromides-buliding-blocks, and the molecular formula is C8H7BrO, Category: bromides-buliding-blocks.

Referemce:
Bromide – Wikipedia,
bromide – Wiktionary

Liu, Xiaoqing; Shang, Yuxuan; Chen, Zhong-Ren published the artcile< Vinyl Groups Containing Tetraphenylethylene Derivatives as Fluorescent Probes Specific for Palladium and the Quenching Mechanism>, Reference of 184239-35-8, the main research area is palladium detection aggregation induced emission fluorescent probe.

We previously reported that a series of tetraphenylethylene (TPE)-containing all-hydrocarbon conjugated polymers exhibited a specific fluorescence quenching by palladium ions (Pd2+). To understand the quenching mechanism, herein we investigate the quenching behaviors of three TPE derivatives in the presence of Pd2+. Each TPE derivative, consisting of TPE unit and terminal vinyl groups, shows an aggregation-induced emission (AIE) and its fluorescence turns off specifically to Pd2+. The sensitivity is enhanced with increasing numbers of vinyl groups in the mols. By time-resolved fluorescence measurement, a dynamic quenching is observed where the fluorescence lifetime is reduced with Pd2+. Specifically, the quenching occurs via the electron transfer in the excited states, as suggested by the disappearance of the stimulated emission band in transient absorption spectra. A theor. calculation on the excited states identifies intermol. electron transfer from TPE derivatives to Pd, especially for electron-rich TPE derivative The mechanism can be general for the design of novel AIE active chemosensors.

Chinese Journal of Chemistry published new progress about Aggregation-induced emission. 184239-35-8 belongs to class bromides-buliding-blocks, and the molecular formula is C26H18Br2, Reference of 184239-35-8.

Referemce:
Bromide – Wikipedia,
bromide – Wiktionary

Gustafson, Jeffrey L.; Lim, Daniel; Miller, Scott J. published the artcile< Dynamic Kinetic Resolution of Biaryl Atropisomers via Peptide-Catalyzed Asymmetric Bromination>, Recommanded Product: Methyl 2-bromo-5-fluorobenzoate, the main research area is dynamics kinetics resolution biaryl atropisomer peptide catalyzed asym bromination.

Despite the widespread use of axially chiral, or atropisomeric, biaryl ligands in modern synthesis and the occurrence of numerous natural products exhibiting axial chirality, few catalytic methods have emerged for the direct asym. preparation of this compound class. Here, the authors present a tripeptide-derived small-mol. catalyst for the dynamic kinetic resolution of racemic biaryl substrates. The reaction proceeds via an atropisomer-selective electrophilic aromatic substitution reaction using simple bromination reagents. The result is an enantioselective synthesis that delivers chiral nonracemic biaryl compounds with excellent optical purity and good isolated chem. yields (in most cases a >95:5 enantiomer ratio and isolated yields of 65 to 87%). A mechanistic model is advanced that accounts for the basis of selectivity observed

Science (Washington, DC, United States) published new progress about Atropisomers. 6942-39-8 belongs to class bromides-buliding-blocks, and the molecular formula is C8H6BrFO2, Recommanded Product: Methyl 2-bromo-5-fluorobenzoate.

Referemce:
Bromide – Wikipedia,
bromide – Wiktionary

Hayashi, Yujiro; Hatano, Yutaro; Mori, Naoki published the artcile< Asymmetric Michael Reaction of Malononitrile and α,β-Unsaturated Aldehydes Catalyzed by Diarylprolinol Silyl Ether>, Electric Literature of 3893-18-3, the main research area is diarylprolinol silyl ether preparation; malononitrile unsaturated aldehyde asym Michael.

An asym. Michael reaction of malononitrile and α,β-unsaturated aldehydes catalyzed by a diarylprolinol silyl ether (NC)2CHCH(R)CH2CH(OMe)2 [R = Me, Ph, 2-furyl, etc.] was developed. Michael products were obtained in good yields and with excellent enantioselectivities without the formation of overreaction products. As a malononitrile moiety can be transformed into an alkoxy or amino carbonyl moiety by oxidative transformation, α-chiral esters or amides with all-carbon quaternary centers can be synthesized with excellent enantioselectivities.

Synlett published new progress about Michael reaction. 3893-18-3 belongs to class bromides-buliding-blocks, and the molecular formula is C9H7BrO, Electric Literature of 3893-18-3.

Referemce:
Bromide – Wikipedia,
bromide – Wiktionary

Shi, Hang; Braun, Augustin; Wang, Lu; Liang, Steven H.; Vasdev, Neil; Ritter, Tobias published the artcile< Synthesis of 18F-Difluoromethylarenes from Aryl (Pseudo) Halides>, Recommanded Product: tert-Butyl (4-bromophenyl)(methyl)carbamate, the main research area is fluoromethyl arene 18F labeled chemoselective preparation; fluoroacetophenone chemoselective preparation bromination fluorination deacylation; coupling aryl halide pseudohalide fluoroacetophenone bromination substitution fluoride deacylation; bromination substitution 18F fluoride deacylation arylfluoromethyl phenyl ketone; aryl (pseudo) halides; difluoromethylarenes; fluorine-18; positron emission tomography; radiopharmaceuticals.

A general, operationally simple, and chemoselective method for the synthesis of [18F]difluoromethylarenes such as I (R = 18FFCH) from [18F]fluoride and aryl chlorides, bromides, iodides, and triflates or pseudohalides such as I (R = TfO) is reported. Coupling of the aryl halides or pseudohalides to α-fluoroacetophenone in the presence of a palladium biphenylamine precatalyst yields α-fluoro-α-arylmethyl Ph ketones such as I (R = PhCOCHF); α-bromination and substitution with [18F]fluoride, tetraethylammonium bromide, and N-bromophthalimide in acetonitrile and chlorobenzene followed by deacylation with aqueous KOH yielded mono-[18F]-labeled difluoromethylarenes such as I (R = 18FFCH) in 10-60% radiochem. yields. The method was used to prepared 18F-difluoromethylated analogs of pharmaceuticals such as Claritin, fluoxetine (Prozac), and DAA1106.

Angewandte Chemie, International Edition published new progress about Aryl bromides Role: RCT (Reactant), RACT (Reactant or Reagent). 639520-70-0 belongs to class bromides-buliding-blocks, and the molecular formula is C12H16BrNO2, Recommanded Product: tert-Butyl (4-bromophenyl)(methyl)carbamate.

Referemce:
Bromide – Wikipedia,
bromide – Wiktionary