Ying-yeung Yeung

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Organization: National University of Singapore

Department: Department of Chemistry

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TOPICS

Organic Chemistry

Asymmetric Synthesis Organocatalysis Hypervalent Iodine

Chemicals
References

Indole-Catalyzed Bromolactonization in Lipophilic Solvent: A Solid–Liquid Phase Transfer Approach

Co-reporter:Tao Chen, Thomas Jian Yao Foo, and Ying-Yeung Yeung

ACS Catalysis 2015 Volume 5(Issue 8) pp:4751

Publication Date(Web):July 14, 2015

DOI:10.1021/acscatal.5b01182

We have developed a novel indole-catalyzed bromolactonization of olefinic acids. The reaction could be conducted in lipophilic solvent through a solid–liquid phase transfer mechanism. This catalytic protocol has been applied to the synthesis of base-sensitive bromolactones.Keywords: halolactonization; indole; lactones; organocatalysis; phase transfer

Lewis Basic Sulfide Catalyzed Electrophilic Bromocyclization of Cyclopropylmethyl Amide

Co-reporter:Ying-Chieh Wong, Zhihai Ke, and Ying-Yeung Yeung

Organic Letters 2015 Volume 17(Issue 20) pp:4944-4947

Publication Date(Web):October 6, 2015

DOI:10.1021/acs.orglett.5b02557

A Lewis basic sulfide catalyzed electrophilic bromocyclization of cyclopropylmethyl amide has been developed. The catalytic protocol is applicable to both 1,1- and 1,2-substituted cyclopropylmethyl amides, giving oxazolines and oxazines in good yields and excellent diastereoselectivity.

Catalytic and Highly Enantioselective Selenolactonization

Co-reporter:Wenxue Niu and Ying-Yeung Yeung

Organic Letters 2015 Volume 17(Issue 7) pp:1660-1663

Publication Date(Web):March 12, 2015

DOI:10.1021/acs.orglett.5b00377

An enantioselective selenolactonization of olefinic acids has been developed using (DHQD)2PHAL as the catalyst. Structurally simple and commercially available N-phenylselenophthalimide was used as the electrophilic selenium reagent. The corresponding selenolactones could be obtained with up to 96% ee.

Carbamate-Catalyzed Enantioselective Bromolactamization

Co-reporter:Dr. Yi An Cheng;Wesley Zongrong Yu;Dr. Ying-Yeung Yeung

Angewandte Chemie International Edition 2015 Volume 54( Issue 41) pp:12102-12106

Publication Date(Web):

DOI:10.1002/anie.201504724

Abstract

A highly facile, efficient, and enantioselective bromolactamization of olefinic amides was effected by a carbamate catalyst and ethanol additive. The amide substrates underwent N-cyclization predominantly to give a diverse range of enantioenriched bromolactam products containing up to two stereogenic centers.

Carbamate-Catalyzed Enantioselective Bromolactamization

Co-reporter:Dr. Yi An Cheng;Wesley Zongrong Yu;Dr. Ying-Yeung Yeung

Angewandte Chemie 2015 Volume 127( Issue 41) pp:12270-12274

Publication Date(Web):

DOI:10.1002/ange.201504724

Abstract

Catalyst-Free and Metal-Free Electrophilic Bromoamidation of Unactivated Olefins Using the N-Bromosuccinimide/Sulfonamide Protocol

Co-reporter:Wesley Zongrong Yu, Feng Chen, Yi An Cheng, and Ying-Yeung Yeung

The Journal of Organic Chemistry 2015 Volume 80(Issue 5) pp:2815-2821

Publication Date(Web):February 3, 2015

DOI:10.1021/jo502416r

An efficient, catalyst-free, and metal-free bromoamidation of unactivated olefins has been developed. 4-(Trifluoromethyl)benzenesulfonamide and N-bromosuccinimide were used as the nitrogen and halogen sources, respectively. The methodology is applicable to both cyclic and aliphatic olefins.

An Unexpected 2,3-Dihydrofuran Derivative Ring Opening Initiated by Electrophilic Bromination: Scope and Mechanistic Study

Co-reporter:Yi Zhao, Ying-Chieh Wong, and Ying-Yeung Yeung

The Journal of Organic Chemistry 2015 Volume 80(Issue 1) pp:453-459

Publication Date(Web):December 3, 2014

DOI:10.1021/jo502453f

An unexpected 2,3-dihydrofuran ring opening process at the C(4)–C(5) bond has been developed. N-Bromosuccinimide and DABCO were used as the electrophilic halogen source and the catalyst, respectively. Mechanistic study indicates that moisture in the solvent might contribute to the reaction. The resulting brominated product could be further oxidized to yield a synthetically valuable 1,2-diketo building block.

Catalytic Asymmetric Bromoetherification and Desymmetrization of Olefinic 1,3-Diols with C2-Symmetric Sulfides

Co-reporter:Zhihai Ke ; Chong Kiat Tan ; Feng Chen

Journal of the American Chemical Society 2014 Volume 136(Issue 15) pp:5627-5630

Publication Date(Web):April 3, 2014

DOI:10.1021/ja5029155

An enantioselective and highly diastereoselective bromoetherification and desymmetrization of olefinic 1,3-diols has been developed using a C2-symmetric cyclic sulfide catalyst. This methodology has been successfully applied to the synthesis of the key intermediate of an orally active antifungal drug posaconazole (Noxafil).

N-Bromosuccinimide-Induced Aminocyclization–Aziridine Ring-Expansion Cascade: An Asymmetric and Highly Stereoselective Approach toward the Synthesis of Azepane

Co-reporter:Jing Zhou and Ying-Yeung Yeung

Organic Letters 2014 Volume 16(Issue 8) pp:2134-2137

Publication Date(Web):April 1, 2014

DOI:10.1021/ol5005609

A novel N-bromosuccinimide induced aminocyclization–aziridine ring expansion cascade is reported. Substituted azepanes were isolated exclusively in good yields. The azepane products could be transformed into a number of functional molecules including piperidines, a bicyclic amine, and a bridgehead amide.

Diastereoselective synthesis of functionalized pyrrolidines through N-bromosuccinimide-induced aziridine ring expansion cascade of cinnamylaziridine

Co-reporter:Jing Zhou and Ying-Yeung Yeung

Organic & Biomolecular Chemistry 2014 vol. 12(Issue 38) pp:7482-7485

Publication Date(Web):2014/08/06

DOI:10.1039/C4OB01384K

An efficient aziridine ring expansion cascade of cinnamylaziridine has been developed. N-Bromosuccinimide was used as the promoter. The resulting functionalized pyrrolidines are the fundamental units of many useful molecules.

Recent advances in asymmetric intra- and intermolecular halofunctionalizations of alkenes

Co-reporter:Yi An Cheng, Wesley Zongrong Yu and Ying-Yeung Yeung

Organic & Biomolecular Chemistry 2014 vol. 12(Issue 15) pp:2333-2343

Publication Date(Web):12 Feb 2014

DOI:10.1039/C3OB42335B

This review seeks to provide coverage on recent advances in catalytic enantioselective halofunctionalization of alkenes. The aim is to give an overview of various reports, highlighting the new reaction types and strategies developed during the past two years. The scope and challenges of intra- and intermolecular reaction variants are discussed as well.

Mild propargylic oxidation using a diacetoxyiodobenzene/tert-butyl hydroperoxide protocol

Co-reporter:Yi Zhao, Angela Wan Ting Ng, Ying-Yeung Yeung

Tetrahedron Letters 2014 Volume 55(Issue 31) pp:4370-4372

Publication Date(Web):30 July 2014

DOI:10.1016/j.tetlet.2014.06.032

A mild propargylic oxidation of alkynes is reported using a diacetoxyiodobenzene/tert-butyl hydroperoxide (DIB/TBHP) protocol. The reactions proceed smoothly at 0 °C and a number of α,β-unsaturated alkynoic ketones are obtained.

Synthesis of chiral butenolides using amino-thiocarbamate-catalyzed asymmetric bromolactonization

Co-reporter:Chong Kiat Tan, Jun Cheng Er, Ying-Yeung Yeung

Tetrahedron Letters 2014 Volume 55(Issue 6) pp:1243-1246

Publication Date(Web):5 February 2014

DOI:10.1016/j.tetlet.2014.01.009

•Asymmetric bromolactonization of 4,4-disubstituted 3-butenoic acid was achieved.•Cinchonine-derived amino-thiocarbamate was used as the catalyst.•The γ-butanolide products have two stereogenic centers.•The γ-butenolides can be achieved by quenching the reaction under basic condition.•The products are fundamental units of many pharmaceutically important molecules.The asymmetric cyclization of 4,4-disubstituted 3-butenoic acids is studied. Amino-thiocarbamates are used as the catalysts and N-bromosuccinimide is used as the stoichiometric halogen source. The resulting γ-butanolide products are readily converted into the corresponding γ-butenolides (up to 58% ee) derivatives in one-pot.

Synthesis of Reboxetine Intermediate and Carnitine Acetyltransferase Inhibitor via NBS-Induced Electrophilic Multicomponent Reaction

Co-reporter:Jing Zhou and Ying-Yeung Yeung

The Journal of Organic Chemistry 2014 Volume 79(Issue 10) pp:4644-4649

Publication Date(Web):April 17, 2014

DOI:10.1021/jo500609a

N-Bromosuccinimide-induced electrophilic multicomponent reaction has been applied to the synthesis of Reboxetine intermediate, a highly potent selective norepinephrine reuptake inhibitor. By simply changing the olefinic partner, the synthesis of a carnitine acetyltransferase inhibitor, which contains a 2,6,6-trisubstituted morpholine system, can be accomplished.

Desymmetrization of Diolefinic Diols by Enantioselective Amino-thiocarbamate-Catalyzed Bromoetherification: Synthesis of Chiral Spirocycles

Co-reporter:Daniel Weiliang Tay;Dr. Gulice Y. C. Leung;Dr. Ying-Yeung Yeung

Angewandte Chemie International Edition 2014 Volume 53( Issue 20) pp:5161-5164

Publication Date(Web):

DOI:10.1002/anie.201310136

Abstract

A facile, efficient, and highly diastereo- and enantioselective bromoetherification of diolefinic diols has been developed using an amino-thiocarbamate catalyst. Further manipulations of the bromoether products enabled entry into a new class of spirocycles which are distinctively lacking in the literature.

Stereoselective Bromofunctionalization of Alkenes

Co-reporter:Chong Kiat Tan;Wesley Zongrong Yu

Chirality 2014 Volume 26( Issue 7) pp:328-343

Publication Date(Web):

DOI:10.1002/chir.22272

ABSTRACT

The stereoselective bromofunctionalization of alkenes, particularly the enantioselective format, has been a subject of intense research in recent years. The ground-breaking works are documented in recent reviews. On the other hand, this account will provide an insight into our group's approach in tackling the challenges in enantioselective bromocyclization of alkenes as well as the development of diastereoselective N-bromosuccinimide-initiated multicomponent reactions. Chirality 26:328–342, 2013. © 2013 Wiley Periodicals, Inc.

Desymmetrization of Diolefinic Diols by Enantioselective Amino-thiocarbamate-Catalyzed Bromoetherification: Synthesis of Chiral Spirocycles

Co-reporter:Daniel Weiliang Tay;Dr. Gulice Y. C. Leung;Dr. Ying-Yeung Yeung

Angewandte Chemie 2014 Volume 126( Issue 20) pp:5261-5264

Publication Date(Web):

DOI:10.1002/ange.201310136

Abstract

C2-Symmetric Cyclic Selenium-Catalyzed Enantioselective Bromoaminocyclization

Co-reporter:Feng Chen ; Chong Kiat Tan

Journal of the American Chemical Society 2013 Volume 135(Issue 4) pp:1232-1235

Publication Date(Web):January 13, 2013

DOI:10.1021/ja311202e

A catalytic asymmetric bromocyclization of trisubstituted olefinic amides that uses a C2-symmetric mannitol-derived cyclic selenium catalyst and a stoichiometric amount of N-bromophthalimide is reported. The resulting enantioenriched pyrrolidine products, which contain two stereogenic centers, can undergo rearrangement to yield 2,3-disubstituted piperidines with excellent diastereoselectivity and enantiospecificity.

Lewis Basic Selenium Catalyzed Chloroamidation of Olefins Using Nitriles as the Nucleophiles

Co-reporter:Daniel Weiliang Tay, Ivan Tan Tsoi, Jun Cheng Er, Gulice Yiu Chung Leung, and Ying-Yeung Yeung

Organic Letters 2013 Volume 15(Issue 6) pp:1310-1313

Publication Date(Web):March 5, 2013

DOI:10.1021/ol400249x

A Lewis base catalyzed chloroamidation of olefinic substrates was achieved using diphenyl selenide as the catalyst. The reaction conditions are mild and suitable for a wide range of substrates including those which are acid labile.

NBS-Initiated Electrophilic Phenoxyetherification of Olefins

Co-reporter:Zhihai Ke and Ying-Yeung Yeung

Organic Letters 2013 Volume 15(Issue 8) pp:1906-1909

Publication Date(Web):April 1, 2013

DOI:10.1021/ol4005646

A one-pot electrophilic phenoxyetherification using an olefin, a cyclic ether, a phenol, and N-bromosuccinimide has been developed. This type of multicomponent reaction (MCR) is useful in the synthesis of building blocks that are potentially applicable to self-assembly complex construction.

Enantioselective synthesis of 2-substituted and 3-substituted piperidines through a bromoaminocyclization process

Co-reporter:Ling Zhou, Daniel Weiliang Tay, Jie Chen, Gulice Yiu Chung Leung and Ying-Yeung Yeung

Chemical Communications 2013 vol. 49(Issue 39) pp:4412-4414

Publication Date(Web):03 Oct 2012

DOI:10.1039/C2CC36578B

A catalytic enantioselective bromocyclization of olefinic amides using amino-thiocarbamates as the catalysts has been developed. The resulting enantioenriched 2-substituted 3-bromopiperidines can readily be transformed to 3-substituted piperidines through a silver salt-mediated rearrangement. This process has been applied to the synthesis of a dopaminergic drug, Preclamol.

Recent advances in stereoselective bromofunctionalization of alkenes using N-bromoamide reagents

Co-reporter:Chong Kiat Tan and Ying-Yeung Yeung

Chemical Communications 2013 vol. 49(Issue 73) pp:7985-7996

Publication Date(Web):03 Jul 2013

DOI:10.1039/C3CC43950J

Bromination reactions have been made a lot more convenient since the invention of N-bromoamide reagents. These reagents are more easily handled when compared to molecular bromine. In comparison to other halogens, brominating reagents sit in between chlorine and iodine on the reactivity scale, giving them an advantage in some cases. Recently, several important advances in enantioselective bromofunctionalization of alkenes using such reagents have been reported. This article will highlight the challenges and methods to surmount these problems. In addition, this article will also show the use of N-bromoamide reagents in expanding the scope of diastereoselective bromofunctionalization of alkenes. Examples include bromine initiated cyclic ether cascades and novel multicomponent reactions (MCRs).

Oxidative transformation of cyclic ethers/amines to lactones/lactams using a DIB/TBHP protocol

Co-reporter:Yi Zhao, Jascelyn Qian Lin Ang, Angela Wan Ting Ng and Ying-Yeung Yeung

RSC Advances 2013 vol. 3(Issue 43) pp:19765-19768

Publication Date(Web):14 Aug 2013

DOI:10.1039/C3RA44184A

A novel C–H oxidation of cyclic ethers and amines to the corresponding lactones and lactams was developed using a DIB/TBHP protocol. The reaction is mild and no metallic reagent is involved. In addition, study shows that the electronic properties of the substituents could affect the selectivity of oxidation.

Studies on the ring-opening of bicyclic cyclopropanes activated by a carbonyl group

Co-reporter:Xiaojian Jiang, Zonghan Lim, Ying-Yeung Yeung

Tetrahedron Letters 2013 Volume 54(Issue 14) pp:1798-1801

Publication Date(Web):3 April 2013

DOI:10.1016/j.tetlet.2013.01.053

Studies on the Friedel–Crafts reaction between carbonyl bicyclic cyclopropane and electronic-rich aromatic systems were conducted. Lewis acid and iminium cationic activation methods were examined. It was found that the cyclopropane ring-opening was highly dependent on the nature of the counter nucleophile as well as the activation method.

Catalytic, Enantioselective, and Highly Chemoselective Bromocyclization of Olefinic Dicarbonyl Compounds

Co-reporter:Yi Zhao;Dr. Xiaojian Jiang ;Dr. Ying-Yeung Yeung

Angewandte Chemie 2013 Volume 125( Issue 33) pp:8759-8763

Publication Date(Web):

DOI:10.1002/ange.201304107

Catalytic, Enantioselective, and Highly Chemoselective Bromocyclization of Olefinic Dicarbonyl Compounds

Co-reporter:Yi Zhao;Dr. Xiaojian Jiang ;Dr. Ying-Yeung Yeung

Angewandte Chemie International Edition 2013 Volume 52( Issue 33) pp:8597-8601

Publication Date(Web):

DOI:10.1002/anie.201304107

Efficient Medium Ring Size Bromolactonization Using a Sulfur-Based Zwitterionic Organocatalyst

Co-reporter:Yi An Cheng ; Tao Chen ; Chong Kiat Tan ; Jun Jie Heng

Journal of the American Chemical Society 2012 Volume 134(Issue 40) pp:16492-16495

Publication Date(Web):September 21, 2012

DOI:10.1021/ja307210n

Catalytic bromolactonization of long-chain olefinic acids resulting in the efficient synthesis of medium-sized lactones is reported using a zwitterionic catalyst and stoichiometric N-bromosuccinimide halogen source. The reaction was found to be more efficient at 0 °C than at room temperature, which could be attributed to the temperature dependence of the zwitterionic catalyst.

Enantioselective bromolactonization of cis-1,2-disubstituted olefinic acids using an amino-thiocarbamate catalyst

Co-reporter:Chong Kiat Tan, Chencheng Le and Ying-Yeung Yeung

Chemical Communications 2012 vol. 48(Issue 46) pp:5793-5795

Publication Date(Web):20 Mar 2012

DOI:10.1039/C2CC31148H

A facile, highly regio- and enantioselective amino-thiocarbamate-catalyzed bromolactonization of cis-1,2-disubstituted olefinic acids has been developed. The use of the enantio-enriched lactones in the synthesis of chiral synthetic intermediates is also demonstrated.

A highly enantioselective approach towards 2-substituted 3-bromopyrrolidines

Co-reporter:Jie Chen, Ling Zhou and Ying-Yeung Yeung

Organic & Biomolecular Chemistry 2012 vol. 10(Issue 19) pp:3808-3811

Publication Date(Web):07 Mar 2012

DOI:10.1039/C2OB25327E

A facile and highly enantioselective approach towards 2-substituted 3-bromopyrrolidines has been developed. The process involves an amino-thiocarbamate catalyzed bromoaminocyclization of 1,2-disubstituted olefinic amides. The pyrrolidine products could readily be converted into other useful building blocks including a dihydropyrrole and a 2-substituted pyrrolidine.

Oxidative transformation of azides to aryl nitriles using DIB/TBHP: scope and mechanistic insights

Co-reporter:Yi Zhao, Xinying Chew, Gulice Y.C. Leung, Ying-Yeung Yeung

Tetrahedron Letters 2012 Volume 53(Issue 35) pp:4766-4769

Publication Date(Web):29 August 2012

DOI:10.1016/j.tetlet.2012.06.131

Bis(tert-butylperoxy)iodobenzene, generated in situ by the reaction between diacetoxyl iodobenzene (DIB) and tert-butyl hydroperoxide (TBHP), was used in the oxidative transformation of primary azides to nitriles, and secondary azides to ketones.

Enantioselective Bromolactonization Using an S-Alkyl Thiocarbamate Catalyst

Co-reporter:Xiaojian Jiang;Chong Kiat Tan;Dr. Ling Zhou ;Dr. Ying-Yeung Yeung

Angewandte Chemie 2012 Volume 124( Issue 31) pp:7891-7895

Publication Date(Web):

DOI:10.1002/ange.201202079

An Enantioselective Approach toward 3,4-Dihydroisocoumarin through the Bromocyclization of Styrene-type Carboxylic Acids

Co-reporter:Jie Chen, Ling Zhou, Chong Kiat Tan, and Ying-Yeung Yeung

The Journal of Organic Chemistry 2012 Volume 77(Issue 2) pp:999-1009

Publication Date(Web):December 16, 2011

DOI:10.1021/jo202221c

A facile and enantioselective approach toward 3,4-dihydroisocoumarin was developed. The method involved an amino-thiocarbamate catalyzed enantioselective bromocyclization of styrene-type carboxylic acids, yielding 3-bromo-3,4-dihydroisocoumarins with good yields and ee's. 3-Bromo-3,4-dihydroisocoumarins are versatile building blocks for various dihydroisocoumarin derivatives in which the Br group can readily be modified to achieve biologically important 4-O-type and 4-N-type 3,4-dihydroisocoumarin systems. In addition, studies indicated that, by refining some parameters, the synthetically useful 5-exo phthalide products could be achieved with good yields and ee's.

Enantioselective Bromolactonization Using an S-Alkyl Thiocarbamate Catalyst

Co-reporter:Xiaojian Jiang;Chong Kiat Tan;Dr. Ling Zhou ;Dr. Ying-Yeung Yeung

Angewandte Chemie International Edition 2012 Volume 51( Issue 31) pp:7771-7775

Publication Date(Web):

DOI:10.1002/anie.201202079

Enantioselective Bromoaminocyclization Using Amino–Thiocarbamate Catalysts

Co-reporter:Ling Zhou ; Jie Chen ; Chong Kiat Tan

Journal of the American Chemical Society 2011 Volume 133(Issue 24) pp:9164-9167

Publication Date(Web):May 3, 2011

DOI:10.1021/ja201627h

A facile and efficient enantioselective bromoaminocyclization of unsaturated sulfonamides has been developed using an amino–thiocarbamate catalyst. A range of enantioenriched pyrrolidines were prepared with up to 99% yield and 99% ee. The corresponding lactams could be obtained through oxidation of the pyrrolidines.

An Unexpected Oxidation of Unactivated Methylene C–H Using DIB/TBHP Protocol

Co-reporter:Yi Zhao, Wai-Leung Yim, Chong Kiat Tan, and Ying-Yeung Yeung

Organic Letters 2011 Volume 13(Issue 16) pp:4308-4311

Publication Date(Web):July 25, 2011

DOI:10.1021/ol2016466

An in situ generated hypervalent iodine species, bis(tert-butylperoxy)iodobenzene, was used as a peroxy radical source for the oxidation of unreactive, remote, and isolated alkyl (cyclic or aliphatic) esters and amides to the corresponding keto compounds under very mild conditions.

N-Bromosuccinimide Promoted One-Pot Synthesis of Guanidine: Scope and Mechanism

Co-reporter:Ling Zhou, Jie Chen, Jing Zhou, and Ying-Yeung Yeung

Organic Letters 2011 Volume 13(Issue 21) pp:5804-5807

Publication Date(Web):October 11, 2011

DOI:10.1021/ol202402y

A novel electrophilic one-pot guanidine synthesis has been developed using an olefin, a cyanimide, an amine, and N-bromosuccinimide. A number of guanidine derivatives were prepared with good to excellent yields. An rTRTVI precursor was also prepared based on this useful process.

Studies toward Lewis basic thiocarbamate and thiourea mediated bromolactonization: the effect of a trace amount of water on the reactivity and enantioselectivity

Co-reporter:Chong Kiat Tan, Feng Chen, Ying-Yeung Yeung

Tetrahedron Letters 2011 Volume 52(Issue 38) pp:4892-4895

Publication Date(Web):21 September 2011

DOI:10.1016/j.tetlet.2011.07.049

The effects of trace amounts of water on thiocarbamate- and thiourea-catalyzed bromolactonization reactions are studied. It was found that the thiourea- and the N–Me thiocarbamate-catalyzed bromolactonization reactions were sensitive to trace amounts of moisture. In contrast, the N–H thiocarbamate-catalyzed bromolactonization proceeded equally smoothly in both anhydrous and non-anhydrous solvents.

Facile, Efficient, and Catalyst-Free Electrophilic Aminoalkoxylation of Olefins: Scope and Application

Co-reporter:Ling Zhou ; Chong Kiat Tan ; Jing Zhou

Journal of the American Chemical Society 2010 Volume 132(Issue 30) pp:10245-10247

Publication Date(Web):July 14, 2010

DOI:10.1021/ja104168q

A new one-pot electrophilic aminoalkoxylation reaction using olefin, cyclic ether, amine, and N-bromosuccinimide has been developed. The olefinic substrates and the cyclic ether partners can be flexibly varied to produce a range of amino ether derivatives. This novel protocol has been applied in the facile and efficient synthesis of biologically active morpholine compounds.

Asymmetric Bromolactonization Using Amino-thiocarbamate Catalyst

Co-reporter:Ling Zhou ; Chong Kiat Tan ; Xiaojian Jiang ; Feng Chen

Journal of the American Chemical Society 2010 Volume 132(Issue 44) pp:15474-15476

Publication Date(Web):October 14, 2010

DOI:10.1021/ja1048972

A novel amino-thiocarbamate-catalyzed bromolactonization of unsaturated carboxylic acids has been developed. The scope of the reaction is evidenced by 22 examples of γ-lactones with up to 99% yield and 93% ee. The protocol was applied in the enantioselective synthesis of the key intermediates of VLA-4 antagonists.

An Unprecedented Method for the Generation of tert-Butylperoxy Radical Using DIB/TBHP Protocol: Solvent Effect and Application on Allylic Oxidation

Co-reporter:Yi Zhao and Ying-Yeung Yeung

Organic Letters 2010 Volume 12(Issue 9) pp:2128-2131

Publication Date(Web):April 13, 2010

DOI:10.1021/ol100603q

tert-Butylperoxy radical was generated with PhI(OAc)2 and tBuOOH. Ester solvent was found to be critical and the protocol was applied in the allylic oxidation of various olefinic substrates, which gave the corresponding α,β-unsaturated enones in good yield and regioselectivity.

Molecular sieves as an efficient and recyclable catalyst for bromolactonization and bromoacetoxylation reactions

Co-reporter:Feng Chen, Xiaojian Jiang, Jun Cheng Er, Ying-Yeung Yeung

Tetrahedron Letters 2010 Volume 51(Issue 26) pp:3433-3435

Publication Date(Web):30 June 2010

DOI:10.1016/j.tetlet.2010.04.113

Bromolactonization of unsaturated acids and bromoacetoxylation of olefins proceeded smoothly in the presence of molecular sieves and N-bromosuccinimide. The molecular sieves can be recycled and reused, and the halogen carrier can be recovered effectively.

Diastereoselective synthesis of functionalized pyrrolidines through N-bromosuccinimide-induced aziridine ring expansion cascade of cinnamylaziridine

Co-reporter:Jing Zhou and Ying-Yeung Yeung

Organic & Biomolecular Chemistry 2014 - vol. 12(Issue 38) pp:NaN7485-7485

Publication Date(Web):2014/08/06

DOI:10.1039/C4OB01384K

Recent advances in asymmetric intra- and intermolecular halofunctionalizations of alkenes

Co-reporter:Yi An Cheng, Wesley Zongrong Yu and Ying-Yeung Yeung

Organic & Biomolecular Chemistry 2014 - vol. 12(Issue 15) pp:NaN2343-2343

Publication Date(Web):2014/02/12

DOI:10.1039/C3OB42335B

A highly enantioselective approach towards 2-substituted 3-bromopyrrolidines

Co-reporter:Jie Chen, Ling Zhou and Ying-Yeung Yeung