Pixu Li

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Name: 李丕旭; PiXu Li

Organization: Soochow University , China

Department: College of Chemistry

Title: Associate Professor(PhD)

TOPICS

Organic Chemistry

Formylation

Chemicals
References

Visible-light-mediated benzylic sp3 C–H bond functionalization to C–Br or C–N bond

Co-reporter:Tianyuan Hou, Ping Lu, Pixu Li

Tetrahedron Letters 2016 Volume 57(Issue 21) pp:2273-2276

Publication Date(Web):25 May 2016

DOI:10.1016/j.tetlet.2016.04.036

•Direct conversion of an unactivated benzylic C–H bond to C–Br or C–N bonds under visible light photoredox conditions.•A mild, selective, and practical monobromination protocol through C–H activation/C–X formation.•A new approach to the C–H amination.A visible-light-promoted functionalization of unactivated benzylic sp3 C–H bonds was developed. Ethylbenzene derivatives were converted to the corresponding benzyl bromides or afforded benzylamine derivatives in a one-pot manner under visible light photoredox conditions.

Visible-Light-Promoted (Phenylsulfonyl)methylation of Electron-Rich Heteroarenes and N-Arylacrylamides

Co-reporter:Fei Liu and Pixu Li

The Journal of Organic Chemistry 2016 Volume 81(Issue 16) pp:6972-6979

Publication Date(Web):May 27, 2016

DOI:10.1021/acs.joc.6b00689

Visible-light-promoted radical (phenylsulfonyl)methylation reactions of electron-rich heteroarenes and N-arylacrylamides have been developed starting from bromomethyl phenyl sulfone derivatives. This method provides a mild and efficient access to various (phenylsulfonyl)methylated compounds.

Visible-Light-Promoted Conversion of Alkyl Benzyl Ether to Alkyl Ester or Alcohol via O-α-sp3 C–H Cleavage

Co-reporter:Ping Lu, Tianyuan Hou, Xiangyong Gu, and Pixu Li

Organic Letters 2015 Volume 17(Issue 8) pp:1954-1957

Publication Date(Web):April 2, 2015

DOI:10.1021/acs.orglett.5b00663

A mild and high-yielding visible-light-promoted conversion of alkyl benzyl ethers to the alkyl esters or alkyl alcohols was developed. Mechanistic studies provided evidence for a radical chain reaction involving the homolytic cleavage of O-α-sp3 C–H bonds in the substrate as one of the propagation steps. We propose that α-bromoethers are key intermediates in the transformation.

Aerobic Transition-Metal-Free Visible-Light Photoredox Indole C-3 Formylation Reaction

Co-reporter:Xiang Li, Xiangyong Gu, Yongjuan Li, and Pixu Li

ACS Catalysis 2014 Volume 4(Issue 6) pp:1897

Publication Date(Web):May 5, 2014

DOI:10.1021/cs5005129

An aerobic visible-light-promoted indole C-3 formylation reaction catalyzed by Rose Bengal has been developed. This transition-metal-free process employs molecular oxygen as the terminal oxidant and uses TMEDA as the one-carbon source through C–N bond cleavage. The reaction is compatible with a variety of functional groups.Keywords: aerobic oxidation; indole formylation; Rose Bengal; transition-metal-free; visible light photoredox

TEMPO-Mediated Oxidation of Primary Alcohols to Aldehydes under Visible Light and Air

Co-reporter:Dongwang Liu;Hongxia Zhou;Xiangyong Gu;Xiaoqin Shen

Chinese Journal of Chemistry 2014 Volume 32( Issue 2) pp:117-122

Publication Date(Web):

DOI:10.1002/cjoc.201300541

Abstract

A homogeneous visible light photoredox TEMPO-mediated selective oxidation of primary alcohols to the corresponding carbonyl compounds was developed using molecular oxygen from air as the terminal oxidant. Ru(bpy)₃(PF₆)₂ (bpy: bipyridyl) and Ir(dtb-bpy)(ppy)₂(PF₆) (dtb-bpy: 4,4′-di-tert-butyl-2,2′-bipyridyl; ppy: 2-phenylpyridine) were used as the sensitizers.

Visible-Light-Mediated 1,2-Acyl Migration: The Reaction of Secondary Enamino Ketones with Singlet Oxygen

Co-reporter:Weigang Fan ;Dr. Pixu Li

Angewandte Chemie 2014 Volume 126( Issue 45) pp:12397-12400

Publication Date(Web):

DOI:10.1002/ange.201407413

Abstract

Secondary enaminones were oxidized by photochemically generated singlet oxygen, followed by nucleophilic addition of alcohol and an unexpected 1,2-acyl migration to afford quaternary amino acid derivatives. An ene-type reaction pathway is proposed. It is distinctively different from the typical [2+2] addition of singlet oxygen to a CC bond pathway.

Visible-Light-Mediated 1,2-Acyl Migration: The Reaction of Secondary Enamino Ketones with Singlet Oxygen

Co-reporter:Weigang Fan ;Dr. Pixu Li

Angewandte Chemie International Edition 2014 Volume 53( Issue 45) pp:12201-12204

Publication Date(Web):

DOI:10.1002/anie.201407413

Abstract

A Visible-Light-Promoted Aerobic Metal-Free C-3 Thiocyanation of Indoles

Co-reporter:Weigang Fan, Qi Yang, Fengshan Xu, and Pixu Li

The Journal of Organic Chemistry 2014 Volume 79(Issue 21) pp:10588-10592

Publication Date(Web):October 9, 2014

DOI:10.1021/jo5015799

A simple and efficient visible-light-promoted method for the C-3 thiocyanation of indoles has been developed. The transformation uses Rose Bengal as the photocatalyst and air as the terminal oxidant. The reaction is mild, high-yielding, and environmentally benign.

Room-Temperature Ligand-Free Pd/C-Catalyzed C–S Bond Formation: Synthesis of 2-Substituted Benzothiazoles

Co-reporter:Yannan Cheng, Qian Peng, Weigang Fan, and Pixu Li

The Journal of Organic Chemistry 2014 Volume 79(Issue 12) pp:5812-5819

Publication Date(Web):May 22, 2014

DOI:10.1021/jo5002752

The synthesis of 2-substituted benzothiazoles has been achieved via cyclization of o-iodothiobenzanilide derivatives using Pd/C as the catalyst at room temperature. The protocol is ligand-free, additive-free, and high-yielding and involves very mild conditions.

A simple metal-free catalytic sulfoxidation under visible light and air

Co-reporter:Xiangyong Gu, Xiang Li, Yahong Chai, Qi Yang, Pixu Li and Yingming Yao

Green Chemistry 2013 vol. 15(Issue 2) pp:357-361

Publication Date(Web):10 Dec 2012

DOI:10.1039/C2GC36683E

A metal-free aerobic selective sulfoxidation photosensitized by Rose Bengal or solid-supported Rose Bengal has been developed. The reaction utilizes visible light as the driving force and molecular oxygen as the oxidant. Among the advantages of the developed method are its high efficiency and selectivity, extremely simple operation and workup procedure, and minimal waste generation.

Visible-Light Photoredox in Homolytic Aromatic Substitution: Direct Arylation of Arenes with Aryl Halides

Co-reporter:Yannan Cheng, Xiangyong Gu, and Pixu Li

Organic Letters 2013 Volume 15(Issue 11) pp:2664-2667

Publication Date(Web):May 21, 2013

DOI:10.1021/ol400946k

Direct arylation of unactivated arenes or heteroarenes with aryl halides could be carried out in the presence of potassium tert-butoxide and dimethyl sulfoxide under visible-light irradiation. Ir(ppy)3 was found to be an effective photoredox catalyst for this reaction. The reactions of aryl iodides occurred at room temperature. Elevated temperature was required for aryl bromides. Homolytic aromatic substitution was proposed to be the operative reaction pathway.

Visible-Light-Mediated Nucleophilic Addition of an α-Aminoalkyl Radical to Isocyanate or Isothiocyanate

Co-reporter:Hongxia Zhou, Ping Lu, Xiangyong Gu, and Pixu Li

Organic Letters 2013 Volume 15(Issue 22) pp:5646-5649

Publication Date(Web):October 28, 2013

DOI:10.1021/ol402573j

A visible-light photoredox synthesis of α-amino amide or α-amino thioamide from N,N-dimethylaniline derivatives and aryl isocyanate or aryl isothiocyanate was developed. Bis[2-(4,6-difluorophenyl)pyridinato-C2,N](picolinato)iridium(III) (FIrpic) was found to be the effective catalyst among six catalysts screened. The reaction involves generation of α-aminoalkyl radicals from tertiary amines, followed by radical addition to the electron-deficient carbon of isocyanate and isothiocyanate.

Visible light photoredox atom transfer Ueno–Stork reaction

Co-reporter:Xiangyong Gu, Ping Lu, Weigang Fan, Pixu Li and Yingming Yao

Organic & Biomolecular Chemistry 2013 vol. 11(Issue 41) pp:7088-7091

Publication Date(Web):03 Sep 2013

DOI:10.1039/C3OB41600C

A visible light-promoted atom transfer Ueno–Stork reaction was developed using Ir(ppy)2(dtb-bpy)PF6 as the sensitizer. 2-Iodoethyl propargyl ethers or 2-iodoethyl allyl ethers were used as the radical precursors to construct tetrahydrofuran-containing fused [6,5] and [5,5] bicyclic frameworks.

Intermolecular Visible-Light Photoredox Atom-Transfer Radical [3+2]-Cyclization of 2-(Iodomethyl)cyclopropane-1,1-dicarboxylate with Alkenes and Alkynes

Co-reporter:Xiangyong Gu;Xiang Li;Yue Qu;Qi Yang;Yingming Yao

Chemistry - A European Journal 2013 Volume 19( Issue 36) pp:11878-11882

Publication Date(Web):

DOI:10.1002/chem.201301943

Aerobic Visible-Light Photoredox Radical C–H Functionalization: Catalytic Synthesis of 2-Substituted Benzothiazoles

Co-reporter:Yannan Cheng, Jun Yang, Yue Qu, and Pixu Li

Organic Letters 2012 Volume 14(Issue 1) pp:98-101

Publication Date(Web):December 6, 2011

DOI:10.1021/ol2028866

An aerobic visible-light driven photoredox catalytic formation of 2-substituted benzothiazoles through radical cyclization of thioanilides has been accomplished. The reaction features C–H functionalization and C–S bond formation with no direct metal involvement except the sensitizer. The reaction highlights the following: (1) visible-light is the reaction driving force; (2) molecular oxygen is the terminal oxidant, and (3) water is the only byproduct.

Visible light photoredox atom transfer Ueno–Stork reaction

Co-reporter:Xiangyong Gu, Ping Lu, Weigang Fan, Pixu Li and Yingming Yao

Organic & Biomolecular Chemistry 2013 - vol. 11(Issue 41) pp:NaN7091-7091

Publication Date(Web):2013/09/03

DOI:10.1039/C3OB41600C