Yunfei Du

Name: 杜云飞

Organization: Tianjin University , China

Department: School of Pharmaceutical Science and Technology

Title: Professor(PhD)

Chemicals
References

TBHP/TBAI-Mediated Oxidative Cascade Reaction Consisting of Dimerization, Cyclization, and 1,2-Aryl Migration: Metal-Free Synthesis of Pyrrolin-4-ones and Highly Substituted Pyrroles

Co-reporter:Xiaoyuan Zhao, Yong Zhang, Jun Deng, Daisy Zhang-Negrerie, and Yunfei Du

The Journal of Organic Chemistry December 1, 2017 Volume 82(Issue 23) pp:12682-12682

Publication Date(Web):October 18, 2017

DOI:10.1021/acs.joc.7b02491

Treatment of enamino esters with TBHP (t-butylhydroperoxide) and TBAI (t-butylammonium iodide) in HFIP (hexafluoroisopropanol) was found to afford a variety of substituted pyrrolin-4-one compounds. This metal-free oxidative cascade reaction consists of the key steps of coupling of two radical intermediates, an intramolecular ring closure, and an exclusive 1,2-aryl radical migration. Upon treatment with a base, the obtained pyrrolin-4-ones could be converted to the highly substituted pyrrole compounds.

Iodocyclization of N-Arylpropynamides Mediated by Hypervalent Iodine Reagent: Divergent Synthesis of Iodinated Quinolin-2-ones and Spiro[4,5]trienones

Co-reporter:Ying Zhou, Xiang Zhang, Yong Zhang, Linxin Ruan, Jiacheng Zhang, Daisy Zhang-Negrerie, and Yunfei Du

Organic Letters 2017 Volume 19(Issue 1) pp:150-153

Publication Date(Web):December 21, 2016

DOI:10.1021/acs.orglett.6b03455

PhI(OCOCF3)2 acts as both a nonmetal oxidant and an iodination reagent to trigger iodocyclization of N-arylpropynamides while selectively affording iodinated quinolin-2-ones or the spiro[4,5]trienone skeleton, depending on the substituent pattern. In cases where the N-arylpropynamide bears a para-fluorine on the aniline ring, the spiro compound is formed via an exclusive defluorination process; otherwise, the product was quinolin-2-one.

Transition Metal-Free Oxidative Cross-Coupling C(sp2)–C(sp3) Bond Formation: Regioselective C-3 Alkylation of Coumarins with Tertiary Amines

Co-reporter:Longyang Dian;Daisy Zhang-Negrerie

Advanced Synthesis & Catalysis 2017 Volume 359(Issue 18) pp:3090-3094

Publication Date(Web):2017/09/18

DOI:10.1002/adsc.201700521

AbstractA novel transition-metal-free regioselective C-3 alkylation of coumarins was realized under mild reaction conditions. Various coumarins and tertiary amines smoothly underwent direct C(sp2)–C(sp3) bond formation in the presence of (n-Bu)4NI as the catalyst and t-BuOOH as the oxidant.

A Tandem Ring Opening/Closure Reaction in A BF3-Mediated Rearrangement of Spirooxindoles

Co-reporter:Xuliang Guo;Qingyu Xing;Kunhua Lei;Daisy Zhang-Negrerie;Kang Zhao

Advanced Synthesis & Catalysis 2017 Volume 359(Issue 24) pp:4393-4398

Publication Date(Web):2017/12/19

DOI:10.1002/adsc.201700728

AbstractTreatment of the readily accessible spiro-cyclohexadienones from the PhI(OCOCF3)2-mediated spiro-cyclization of N-substituted benzanilides, with BF3⋅Et2O initiates a tandem ring opening/closure reaction leading to the formation of the biologically interesting 8-hydroxy-phenanthridin-6(5H)-one compounds. This unique rearrangement pattern involves the ‘migration’ of the electron-deficient N-methyl carbamoyl moiety rather than the electron-rich aryl group as observed and reported previously in all other similar transformations.

PhI(OCOCF3)2-Mediated Construction of a 2-Spiropseudoindoxyl Skeleton via Cascade Annulation of 2-Sulfonamido-N-phenylpropiolamide Derivatives

Co-reporter:Bobo Zhang, Xiang Zhang, Bei Hu, Desong Sun, Senlin Wang, Daisy Zhang-Negrerie, and Yunfei Du

Organic Letters 2017 Volume 19(Issue 4) pp:

Publication Date(Web):January 30, 2017

DOI:10.1021/acs.orglett.7b00058

A cascade annulation of 2-sulfonamido-N-phenylpropiolamide derivatives leading to the construction of the 2-spiropseudoindoxyl skeleton was realized under mild conditions with phenyliodine(III) bis(trifluoroacetate) (PIFA) as the sole oxidant. This metal-free spirocyclization process is suggested to encompass a sequential C(sp2)–C(sp) and C(sp2)–N bond formation with the concomitant introduction of a carbonyl oxygen.

Chiral Aryliodine-Mediated Enantioselective Organocatalytic Spirocyclization: Synthesis of Spirofurooxindoles via Cascade Oxidative C–O and C–C Bond Formation

Co-reporter:Yang Cao, Xiang Zhang, Guangyu Lin, Daisy Zhang-Negrerie, and Yunfei Du

Organic Letters 2016 Volume 18(Issue 21) pp:5580-5583

Publication Date(Web):October 21, 2016

DOI:10.1021/acs.orglett.6b02816

An enantioselective organocatalytic oxidative spirocyclization of alkyl 3-oxopentanedioate monoamide derivatives leading to the formation of diverse spirofurooxindoles with high enantioselectivity has been realized via chiral aryliodine-mediated cascade C–O and C–C bond formations. The reaction is postulated to proceed via oxidative C–O bond formation followed by oxidative C–C bond formation, with the latter being the enantioselectivity-determining step.

Cu(OAc)2-Mediated Cascade Annulation of Diarylalkyne Sulfonamides through Dual C–N Bond Formation: Synthesis of 5,10-Dihydroindolo[3,2-b]indoles

Co-reporter:Junchao Yu, Daisy Zhang-Negrerie, and Yunfei Du

Organic Letters 2016 Volume 18(Issue 14) pp:3322-3325

Publication Date(Web):July 1, 2016

DOI:10.1021/acs.orglett.6b01343

An unusual cascade reaction featuring annulation of diarylalkyne sulfonamides to form 5,10-dihydroindolo[3,2-b]indoles has been realized with Cu(OAc)2 as the sole oxidant. This unprecedented process encompasses two sequential C–N bond formations, allowing for an efficient synthesis of the biologically important indoloindole derivatives.

Cobalt-Catalyzed Twofold Direct C(sp2)C(sp3) Bond Coupling: Regioselective C-3 Alkylation of Coumarins with (Cyclo)alkyl Ethers

Co-reporter:Longyang Dian;Hui Zhao;Daisy Zhang-Negrerie

Advanced Synthesis & Catalysis 2016 Volume 358( Issue 15) pp:2422-2426

Publication Date(Web):

DOI:10.1002/adsc.201600349

Oxidative Coupling of Enamines and Disulfides via Tetrabutylammonium Iodide/tert-Butyl Hydroperoxide-Mediated Intermolecular Oxidative C(sp2)S Bond Formation Under Transition Metal-Free Conditions

Co-reporter:Jiyun Sun;Daisy Zhang-Negrerie

Advanced Synthesis & Catalysis 2016 Volume 358( Issue 13) pp:2035-2040

Publication Date(Web):

DOI:10.1002/adsc.201501099

TBHP/CoCl2-Mediated Intramolecular Oxidative Cyclization of N-(2-Formylphenyl)amides: An Approach to the Construction of 4H-3,1-Benzoxazin-4-ones

Co-reporter:Junchao Yu;Daisy Zhang-Negrerie

European Journal of Organic Chemistry 2016 Volume 2016( Issue 3) pp:562-568

Publication Date(Web):

DOI:10.1002/ejoc.201501359

Abstract

The intramolecular oxidative cyclization of N-(2-formylphenyl)amides has been realized through an oxidative C(sp²)–O(sp²) bond-forming reaction between an aldehyde carbon and amide oxygen. This new strategy, which uses tert-butyl hydroperoxide (TBHP) as an oxidant and CoCl₂ as the catalyst, allows for the efficient Co-catalyzed synthesis of useful benzoxazin-4-one derivatives and features readily available starting materials and mild reaction conditions.

Ring-Contraction Disproportionation/Spirocyclization Cascade Reaction of Isochromeno[4,3-b]indol-5(11H)-ones: Synthesis of N-Unsubstituted Spirocycles

Co-reporter:Xiang Zhang, Guangshuai Zhou, Yong Zhang, Daisy Zhang-Negrerie, Yunfei Du, and Kang Zhao

The Journal of Organic Chemistry 2016 Volume 81(Issue 22) pp:11397-11403

Publication Date(Web):October 18, 2016

DOI:10.1021/acs.joc.6b01957

An efficient ring-contraction reaction of isochromeno[4,3-b]indol-5(11H)-ones via a nucleophile-induced disproportionation/spirocyclization cascade process has been developed under mild conditions. The process realized the conversion of isochromeno[4,3-b]indol-5(11H)-ones into N-unsubstituted spiro[indoline-2,1′-isobenzofuran]-3,3′-diones and spiro[indoline-2,1′-isoindoline]-3,3′-diones in the absence of a transition-metal catalyst or oxidant. Gram-scale reaction further demonstrated the practicability of the protocol.

Metal-Free Synthesis of 3-Arylquinolin-2-ones from Acrylic Amides via a Highly Regioselective 1,2-Aryl Migration: An Experimental and Computational Study

Co-reporter:Le Liu, Tonghuan Zhang, Yun-Fang Yang, Daisy Zhang-Negrerie, Xinhao Zhang, Yunfei Du, Yun-Dong Wu, and Kang Zhao

The Journal of Organic Chemistry 2016 Volume 81(Issue 10) pp:4058-4065

Publication Date(Web):April 28, 2016

DOI:10.1021/acs.joc.6b00345

Combined experimental and theoretical investigations into the phenyliodine bis(trifluoroacetate) (PIFA)-mediated reaction of N-arylcinnamamide to produce 3-arylquinolin-2-one derivatives have been conducted. High regioselectivity during the aryl migration process was observed in 3,3-disubstituted acrylamides. Density functional theory calculation was conducted in an attempt to understand the mechanism and the origin of the regioselectivity. On the basis of both the experimental and the theoretical results, a mechanism involving an oxidative annulation, followed by an aryl migration, has been proposed. The annulation is the regioselectivity determining step.

Intramolecular Functionalization of Benzylic Methylene Adjacent to the Ring Nitrogen Atom in N-Aryltetrahydroisoquinoline Derivatives

Co-reporter:Liu Yang, Daisy Zhang-Negrerie, Kang Zhao, and Yunfei Du

The Journal of Organic Chemistry 2016 Volume 81(Issue 8) pp:3372-3379

Publication Date(Web):March 16, 2016

DOI:10.1021/acs.joc.5b02443

Functionalization at the benzylic methylene group that is adjacent to the ring nitrogen atom in a series of N-aryltetrahydroisoquinoline compounds has been realized through intramolecular cross-dehydrogenative coupling reactions. The presented transformation provided straightforward access to the formation of C(sp3)–Y (Y = C, N or O) bond via I(III) reagent.

Hypervalent Iodine-Mediated Intramolecular trans-Aminocarboxylation and Oxoaminocarboxylation of Alkynes: Divergent Cascade Annulations of Isocoumarins under Metal-Free Conditions

Co-reporter:Xiang Zhang, Wenjuan Hou, Daisy Zhang-Negrerie, Kang Zhao, and Yunfei Du

Organic Letters 2015 Volume 17(Issue 21) pp:5252-5255

Publication Date(Web):October 12, 2015

DOI:10.1021/acs.orglett.5b02611

An exclusive trans-aminocarboxylation and oxoaminocarboxylation of diarylalkynes were realized through hypervalent iodine-mediated cascade annulations under metal-free conditions, leading to divergent assembly of fused or spiro polycyclic heterocycles with a dosage of the hypervalent iodine oxidant. The mechanisms for the formation of both products are proposed.

Organocatalytic Radical Involved Oxidative Cross-Coupling of N-Hydroxyphthalimide with Benzylic and Allylic Hydrocarbons

Co-reporter:Longyang Dian;Sisi Wang;Daisy Zhang-Negrerie

Advanced Synthesis & Catalysis 2015 Volume 357( Issue 18) pp:3836-3842

Publication Date(Web):

DOI:10.1002/adsc.201500623

NIS-mediated intramolecular oxidative α-functionalization of tertiary amines: transition metal-free synthesis of 1,2-dihydro-(4H)-3,1-benzoxazin-4-one derivatives

Co-reporter:Le Liu, Liang Du, Daisy Zhang-Negrerie and Yunfei Du

RSC Advances 2015 vol. 5(Issue 38) pp:29774-29781

Publication Date(Web):20 Mar 2015

DOI:10.1039/C5RA03882K

A novel method for direct α-functionalization of tertiary amines via NIS-mediated oxidative C–O bond formation, where NIS serves as both an oxidant and an iodination reagent, has been developed. The method provides easy access to either iodinated or non-iodinated 1,2-dihydro-(4H)-3,1-benzoxazin-4-ones, depending on the nature of the reactant, via a regioselective transition metal-free approach.

Iodine(III)-mediated construction of the dibenzoxazepinone skeleton from 2-(aryloxy)benzamides through oxidative C–N formation

Co-reporter:Xuliang Guo, Daisy Zhang-Negrerie and Yunfei Du

RSC Advances 2015 vol. 5(Issue 115) pp:94732-94736

Publication Date(Web):28 Oct 2015

DOI:10.1039/C5RA20258B

Dibenzoxazepinone compounds were conveniently synthesized from 2-(aryloxy)benzamides through hypervalent iodine(III)-mediated oxidative cyclization under mild reaction conditions.

PhI(OCOCF3)2-Mediated Cyclization of o-(1-Alkynyl)benzamides: Metal-Free Synthesis of 3-Hydroxy-2,3-dihydroisoquinoline-1,4-dione

Co-reporter:Chao Yang, Xiang Zhang, Daisy Zhang-Negrerie, Yunfei Du, and Kang Zhao

The Journal of Organic Chemistry 2015 Volume 80(Issue 10) pp:5320-5328

Publication Date(Web):April 22, 2015

DOI:10.1021/acs.joc.5b00576

The synthesis of an undocumented skeleton of 3-hydroxy-2,3-dihydroisoquinoline-1,4-diones has been discovered and reported. The reaction consists of an intramolecular cyclization of o-(1-alkynyl)benzamides in MeCN/H2O, mediated by metal-free, hypervalent reagent of PhI(OCOCF3)2, followed by an oxidative hydroxylation reaction. The mechanism consisting of two pathways has been proposed and discussed.

Synthesis of Chromeno[2,3-b]indol-11(6H)-one via PhI(OAc)2-Mediated Intramolecular Oxidative C(sp2)–N(H2) Bond Formation

Co-reporter:Jiyun Sun, Daisy Zhang-Negrerie, Yunfei Du, and Kang Zhao

The Journal of Organic Chemistry 2015 Volume 80(Issue 2) pp:1200-1206

Publication Date(Web):December 15, 2014

DOI:10.1021/jo502276b

Various chromeno[2,3-b]indol-11(6H)-ones were conveniently constructed via phenyliodine(III) diacetate (PIDA)-mediated intramolecular oxidative annulation. This method, while realizing a direct oxidative C–N bond formation between an aromatic ring and a pendent free-NH2 moiety, features a metal-free protocol, mild reaction conditions, simple workup, and the ready availability of the starting substrates.

A convenient synthesis of indoloquinolinones via 3-arylation of indole-2-carboxamides and PIDA-mediated C–N bond formation

Co-reporter:Yulin Li, Daisy Zhang-Negrerie, Yunfei Du, Kang Zhao

Tetrahedron 2015 Volume 71(Issue 19) pp:2927-2935

Publication Date(Web):13 May 2015

DOI:10.1016/j.tet.2015.03.048

A series of substituted indoloquinolinones were readily synthesized, via two steps, from indole-2-carboxylic acid and its derivatives: a 3-arylation of indole-2-carboxamides and a subsequent PIDA-mediated oxidative C–N bond formation. The underpinning strategy involves a Cu(I)-promoted C(sp2)–C(sp2) coupling and a PIDA-mediated oxidative C(sp2)–N coupling.

Hypervalent-Iodine-Mediated Cascade Annulation of Diarylalkynes Forming Spiro Heterocycles under Metal-Free Conditions

Co-reporter:Xiang Zhang;Chao Yang;Dr. Daisy Zhang-Negrerie;Dr. Yunfei Du

Chemistry - A European Journal 2015 Volume 21( Issue 13) pp:5193-5198

Publication Date(Web):

DOI:10.1002/chem.201406393

Abstract

An unusual reaction featuring the cascade annulation of internal alkynes to afford spiro heterocycles as the products has been realized for the first time with a hypervalent iodine reagent as the only oxidant. This unprecedented process encompasses not only two sequential CN/CO-bond formations, but also the insertion of a carbonyl oxygen, all in one pot under metal-free conditions.

Organocatalytic amination of alkyl ethers via n-Bu4NI/t-BuOOH-mediated intermolecular oxidative C(sp3)–N bond formation: novel synthesis of hemiaminal ethers

Co-reporter:Longyang Dian, Sisi Wang, Daisy Zhang-Negrerie, Yunfei Du and Kang Zhao

Chemical Communications 2014 vol. 50(Issue 79) pp:11738-11741

Publication Date(Web):13 Aug 2014

DOI:10.1039/C4CC05758A

A novel method for constructing the hemiaminal ether framework under metal-free conditions has been developed. It involves direct organocatalytic amination of alkyl ethers through intermolecular oxidative C(sp3)–N bond formation, with t-BuOOH being the oxidant and n-Bu4NI as the catalyst.

Metal-Free Tandem Oxidative Aryl Migration and C–C Bond Cleavage: Synthesis of α-Ketoamides and Esters from Acrylic Derivatives

Co-reporter:Le Liu, Liang Du, Daisy Zhang-Negrerie, Yunfei Du, and Kang Zhao

Organic Letters 2014 Volume 16(Issue 21) pp:5772-5775

Publication Date(Web):October 24, 2014

DOI:10.1021/ol502834g

A novel tandem metal-free oxidative aryl migration/C–C bond-cleavage reaction, mediated by hypervalent iodine reagent, has been discovered. The presented transformation provided straightforward access to important α-ketoamide and α-ketoester derivatives from readily available acrylic derivatives via a concerted process of 1,2-aryl shift concomitant with C–C bond cleavage.

Direct Oxidative Coupling of Enamines and Electron-Deficient Amines: TBAI/TBHP-Mediated Synthesis of Substituted Diaminoalkenes under Metal-Free Conditions

Co-reporter:Yucheng Yuan, Wenjuan Hou, Daisy Zhang-Negrerie, Kang Zhao, and Yunfei Du

Organic Letters 2014 Volume 16(Issue 20) pp:5410-5413

Publication Date(Web):October 6, 2014

DOI:10.1021/ol5026525

A metal-free cross-coupling of enamines and electron-deficient amines through oxidative C(sp2)–N bond formation has been realized by using TBAI as catalyst and TBHP as oxidant. This novel strategy allows for an efficient organocatalytic synthesis of the synthetically useful diaminoalkene derivatives and is highlighted by appealing features such as readily available of the starting materials, wide substrate scope and transition-metal-free characteristics.

PhICl2 and Wet DMF: An Efficient System for Regioselective Chloroformyloxylation/α-Chlorination of Alkenes/α,β-Unsaturated Compounds

Co-reporter:Le Liu, Daisy Zhang-Negrerie, Yunfei Du, and Kang Zhao

Organic Letters 2014 Volume 16(Issue 2) pp:436-439

Publication Date(Web):January 6, 2014

DOI:10.1021/ol403321n

PhICl2 in wet DMF was found to form an efficient system for realizing difunctionalization of various alkenes and olefinic derivatives possessing a wide range of functional groups. This novel methodology provides convenient access to either regioselective chloroformyloxylated products or α-chlorinated olefinic products, depending on the type of structure of the original unsaturated starting material. The mechanism of the reaction is proposed and discussed.

Intramolecular Metal-Free Oxidative ArylAryl Coupling: An Unusual Hypervalent-Iodine-Mediated Rearrangement of 2-Substituted N-Phenylbenzamides

Co-reporter:Siyun Shang;Dr. Daisy Zhang-Negrerie;Dr. Yunfei Du;Dr. Kang Zhao

Angewandte Chemie International Edition 2014 Volume 53( Issue 24) pp:6216-6219

Publication Date(Web):

DOI:10.1002/anie.201402925

Abstract

Hypervalent-iodine-mediated oxidative coupling of the two aryl groups in either 2-acylamino-N-phenyl-benzamides or 2-hydroxy-N-phenylbenzamides, with concomitant insertion of the ortho-substituted N or O atom into the tether, has been described for the first time. This unusual metal-free rearrangement reaction involves an oxidative C(sp²)C(sp²) aryl–aryl bond formation, cleavage of a C(sp²)C(O) bond, and a lactamization/lactonization. Furthermore, unsymmetrical diaryl compounds can be easily obtained by removing the tether within the cyclized product.

Intramolecular Metal-Free Oxidative ArylAryl Coupling: An Unusual Hypervalent-Iodine-Mediated Rearrangement of 2-Substituted N-Phenylbenzamides

Co-reporter:Siyun Shang;Dr. Daisy Zhang-Negrerie;Dr. Yunfei Du;Dr. Kang Zhao

Angewandte Chemie 2014 Volume 126( Issue 24) pp:6330-6333

Publication Date(Web):

DOI:10.1002/ange.201402925

Abstract

Synthesis of substituted tetrahydron-1H-carbazol-1-one and analogs via PhI(OCOCF3)2-mediated oxidative C–C bond formation

Co-reporter:Hao Shi, Tianjian Guo, Daisy Zhang-Negrerie, Yunfei Du, Kang Zhao

Tetrahedron 2014 70(17) pp: 2753-2760

Publication Date(Web):

DOI:10.1016/j.tet.2014.02.083

PhI(OAc)2-Mediated Intramolecular Oxidative Aryl-Aldehyde Csp2–Csp2 Bond Formation: Metal-Free Synthesis of Acridone Derivatives

Co-reporter:Zisheng Zheng, Longyang Dian, Yucheng Yuan, Daisy Zhang-Negrerie, Yunfei Du, and Kang Zhao

The Journal of Organic Chemistry 2014 Volume 79(Issue 16) pp:7451-7458

Publication Date(Web):July 28, 2014

DOI:10.1021/jo5011697

A metal-free protocol for direct aryl-aldehyde Csp2–Csp2 bond formation via a PhI(OAc)2-mediated intramolecular cross-dehydrogenative coupling (CDC) of various 2-(N-arylamino)aldehydes was developed. The novel methodology requires no need of preactivation of the aldehyde group, is applicable to a large variety of functionalized substrates, and most of all provides a convenient approach to the construction of biologically important acridone derivatives.

Hypervalent Iodine-Mediated Oxygenation of N,N-Diaryl Tertiary Amines: Intramolecular Functionalization of sp3 C–H Bonds Adjacent to Nitrogen

Co-reporter:Ningning Zhang, Ran Cheng, Daisy Zhang-Negrerie, Yunfei Du, and Kang Zhao

The Journal of Organic Chemistry 2014 Volume 79(Issue 21) pp:10581-10587

Publication Date(Web):October 3, 2014

DOI:10.1021/jo5016823

An intramolecular C(sp3)–O bond formation has been achieved via PhI(OAc)2/NaN3-mediated oxygenation of N,N-diaryl tertiary amines. The appealing features of this method include mild reaction conditions, absence of heavy-metal catalysts, and the direct intramolecular functionalization of sp3 C–H bonds adjacent to nitrogen.

PhI(OCOCF3)2-Mediated Intramolecular Oxidative N–N Bond Formation: Metal-Free Synthesis of 1,2,4-Triazolo[1,5-a]pyridines

Co-reporter:Zisheng Zheng, Shuangyu Ma, Linlin Tang, Daisy Zhang-Negrerie, Yunfei Du, and Kang Zhao

The Journal of Organic Chemistry 2014 Volume 79(Issue 10) pp:4687-4693

Publication Date(Web):April 18, 2014

DOI:10.1021/jo500298j

The biologically important 1,2,4-triazolo[1,5-a]pyridines were readily synthesized from N-(pyridin-2-yl)benzimidamides via phenyliodine bis(trifluoroacetate)-mediated intramolecular annulation. This novel strategy allows for the convenient construction of a 1,2,4-triazolo[1,5-a]pyridine skeleton through direct metal-free oxidative N–N bond formation, featuring a short reaction time and high reaction yields.

Construction of 1,4-Benzodiazepine Skeleton from 2-(Arylamino)benzamides through PhI(OAc)2-Mediated Oxidative C–N Bond Formation

Co-reporter:Xuming Li, Liu Yang, Xiang Zhang, Daisy Zhang-Negrerie, Yunfei Du, and Kang Zhao

The Journal of Organic Chemistry 2014 Volume 79(Issue 3) pp:955-962

Publication Date(Web):January 15, 2014

DOI:10.1021/jo402413g

New compounds involving the biologically important 1,4-benzodiazepine skeleton were conveniently constructed from 2-(arylamino)benzamides through PhI(OAc)2-mediated oxidative C–N bond formation. The attractive features of this new synthetic strategy include mild reaction conditions, the heavy-metal-free characteristic of the oxidative coupling process, and the flexibility to tolerate a broad scope of substrates.

Metal-Free Synthesis of 2-Oxindoles via PhI(OAc)2-Mediated Oxidative C–C Bond Formation

Co-reporter:Jinglei Lv, Daisy Zhang-Negrerie, Jun Deng, Yunfei Du, and Kang Zhao

The Journal of Organic Chemistry 2014 Volume 79(Issue 3) pp:1111-1119

Publication Date(Web):January 10, 2014

DOI:10.1021/jo4025539

The series of 3-monofunctionalized 2-oxindoles 2 were conveniently synthesized from reactions between anilide 1 and phenyliodine(III) diacetate (PIDA) through hypervalent iodine mediated C(sp2)–C(sp2) bond formation followed by a subsequent deacylation reaction. This metal-free method, shown to provide direct access to an important oxindole intermediate, could be applied to the total synthesis of naturally occurring horsfiline.

The applications of hypervalent iodine(III) reagents in the constructions of heterocyclic compounds through oxidative coupling reactions

Co-reporter:ZiSheng Zheng;Daisy Zhang-Negrerie;Kang Zhao

Science China Chemistry 2014 Volume 57( Issue 2) pp:189-214

Publication Date(Web):2014 February

DOI:10.1007/s11426-013-5043-1

Hypervalent iodine(III) reagents have been vastly used in many useful organic transformations. In this review article, we highlight the strategies that used the common hypervalent iodine(III) reagents as oxidants to synthesize the heterocyclic compounds, based on the patterns of bond formation during the construction of the heterocyclic backbones.

PhI(OCOCF3)2-Mediated C–C Bond Formation Concomitant with a 1,2-Aryl Shift in a Metal-Free Synthesis of 3-Arylquinolin-2-ones

Co-reporter:Le Liu, Hang Lu, Hong Wang, Chao Yang, Xiang Zhang, Daisy Zhang-Negrerie, Yunfei Du, and Kang Zhao

Organic Letters 2013 Volume 15(Issue 12) pp:2906-2909

Publication Date(Web):May 30, 2013

DOI:10.1021/ol400743r

The reaction of the readily available N-methyl-N-phenylcinnamamides with phenyliodine bis(trifluoroacetate) (PIFA) in the presence of Lewis acids provides a general and efficient assembly of a variety of 3-arylquinolin-2-one compounds. This novel approach features not only metal-free oxidative C(sp2)–C(sp2) bond formation but also an exclusive 1,2-aryl migration.

Formation of Functionalized 2H-Azirines through PhIO-Mediated Trifluoroethoxylation and Azirination of Enamines

Co-reporter:Xiaoqian Sun, Youran Lyu, Daisy Zhang-Negrerie, Yunfei Du, and Kang Zhao

Organic Letters 2013 Volume 15(Issue 24) pp:6222-6225

Publication Date(Web):November 14, 2013

DOI:10.1021/ol4030716

A variety of enaminones and enamine carboxylic esters were converted to trifluoroethoxylated 2H-azirines through reactions with PhIO in trifluoroethanol (TFE). The cascade reaction is postulated to proceed via a PhIO-mediated oxidative trifluoroethoxylation and a subsequent azirination of the α-trifluoroethoxylated enamine intermediates.

Constructions of tetrahydro-γ-carboline skeletons via intramolecular oxidative carbon–carbon bond formation of enamines

Co-reporter:Jinglei Lv, Ji Li, Daisy Zhang-Negrerie, Siyun Shang, Qingzhi Gao, Yunfei Du and Kang Zhao

Organic & Biomolecular Chemistry 2013 vol. 11(Issue 12) pp:1929-1932

Publication Date(Web):05 Feb 2013

DOI:10.1039/C3OB00039G

The synthetically and biologically important 4-methyl and 4-methoxy tetrahydro-γ-carboline compounds were readily synthesized in high yields from an aryl amine and a 5-amino-3-oxopentanoate derivative through a series of reactions of enamination, oxidative annulation, deprotection/lactamization and the final reduction reaction of the carbonyl group. The underpinning strategy involves the oxidative C(sp2)–C(sp2) bond formation realized by either Pd(OAc)2/Cu(OAc)2 or a hypervalent iodine reagent.

Synthesis of coumarins via PIDA/I2-mediated oxidative cyclization of substituted phenylacrylic acids

Co-reporter:Jinming Li, Huiyu Chen, Daisy Zhang-Negrerie, Yunfei Du and Kang Zhao

RSC Advances 2013 vol. 3(Issue 13) pp:4311-4320

Publication Date(Web):18 Jan 2013

DOI:10.1039/C3RA23188G

A variety of functionalized coumarins were synthesized from substituted phenylacrylic acids via PIDA/I2-mediated and irradiation-promoted oxidative carbon–oxygen bond formation. Our studies show that the oxygen in the pendant carboxylic acid group cyclizes favorably to the aryl ring that is cis to it. The main advantages of this method include good functional group tolerance and the transition-metal-free characteristic.

One-pot synthesis of isoxazoles from enaminones: an application of Fe(II) as the catalyst for ring expansion of 2H-azirine intermediates

Co-reporter:Yunhui Zheng, Chao Yang, Daisy Zhang-Negrerie, Yunfei Du, Kang Zhao

Tetrahedron Letters 2013 Volume 54(Issue 46) pp:6157-6160

Publication Date(Web):13 November 2013

DOI:10.1016/j.tetlet.2013.08.079

We report an application of FeCl2 as an inexpensive, nontoxic, and efficient catalyst in a clean ring expansion reaction of 2H-azirine derivatives, an intermediate formed through the PhI(OAc)2-mediated azirination of readily available enaminones. An alternative one-pot protocol for the synthesis of various substituted isoxazoles from their corresponding enaminones has been further established based on this reaction, and herein described.

One-Pot Synthesis of 3-Hydroxyquinolin-2(1H)-ones from N-Phenylacetoacetamide via PhI(OCOCF3)2-Mediated α-Hydroxylation and H2SO4-Promoted Intramolecular Cyclization

Co-reporter:Yucheng Yuan, Rui Yang, Daisy Zhang-Negrerie, Junwei Wang, Yunfei Du, and Kang Zhao

The Journal of Organic Chemistry 2013 Volume 78(Issue 11) pp:5385-5392

Publication Date(Web):May 8, 2013

DOI:10.1021/jo400541s

A clean, one-pot synthesis of the biologically important 3-hydroxyquinolin-2(1H)-one compounds has been realized from the readily available N-phenylacetoacetamide derivatives through a PhI(OCOCF3)2-mediated α-hydroxylation and a H2SO4-promoted intramolecular condensation. The hydroxyl group in the generated α-hydroxylated intermediate can be well tolerated in the second H2SO4-promoted cyclization step.

Synthesis of Diversely Substituted Indoloquinolinones via Pd(II)/Cu(II)-Mediated Oxidative C–C Bond Formation and I(III)-Mediated C–N Bond Formation

Co-reporter:Xiang Zhang, Daisy Zhang-Negrerie, Jun Deng, Yunfei Du, and Kang Zhao

The Journal of Organic Chemistry 2013 Volume 78(Issue 24) pp:12750-12759

Publication Date(Web):November 22, 2013

DOI:10.1021/jo4023292

A series of indoloquinolinones bearing different aromatic substitutents were readily synthesized starting from an aryl amine, a methyl 3-oxo-3-phenylpropanoate derivative, and methoxylamine through a series of reactions of coupling/enamination, oxidative annulation, a one-pot sequence of N-alkylation, saponification and methoxyamidation, and final intramolecular oxidative C–N bond formation. The underpinning of the strategy entails Pd(OAc)2/Cu(OAc)2-mediated oxidative C(sp2)–C(sp2) bond formation and I(III)-mediated oxidative C(sp2)–N bond formation.

Direct Conversion of N-Alkoxyamides to Carboxylic Esters through Tandem NBS-Mediated Oxidative Homocoupling and Thermal Denitrogenation

Co-reporter:Ningning Zhang, Rui Yang, Daisy Zhang-Negrerie, Yunfei Du, and Kang Zhao

The Journal of Organic Chemistry 2013 Volume 78(Issue 17) pp:8705-8711

Publication Date(Web):August 8, 2013

DOI:10.1021/jo401435v

Treatment of N-alkoxyamides with NBS in toluene was found to conveniently afford the corresponding carboxylic esters, including those bearing a bulky or long-chain substituent, in satisfactory to excellent yields. This approach not only represents a convenient and economic approach to a direct transformation of an alkoxyamide moiety into the carboxylic ester functional group, via oxidative homocoupling and the subsequent thermal denitrogenation, but also facilitates the synthesis of sterically hindered carboxylic esters.

Phenyliodine Bis(trifluoroacetate)-Mediated Oxidative C–C Bond Formation: Synthesis of 3-Hydroxy-2-oxindoles and Spirooxindoles from Anilides

Co-reporter:Junwei Wang, Yucheng Yuan, Rui Xiong, Daisy Zhang-Negrerie, Yunfei Du, and Kang Zhao

Organic Letters 2012 Volume 14(Issue 9) pp:2210-2213

Publication Date(Web):April 12, 2012

DOI:10.1021/ol300418h

The reaction of phenyliodine bis(trifluoroacetate) (PIFA) with a series of anilides 1 (E = CO2Et) in CF3CH2OH was found to give 3-hydroxy-2-oxindole derivatives 2, while that with various anilides 1′ (E = CON(R4)Ar) afforded the C2-symmetric or unsymmetric spirooxindoles 3. These processes feature a metal-free oxidative C(sp2)–C(sp3) bond formation, followed by oxidative hydroxylation or spirocyclization.

Direct β-Acyloxylation of Enamines via PhIO-Mediated Intermolecular Oxidative C–O Bond Formation and Its Application to the Synthesis of Oxazoles

Co-reporter:Xin Liu, Ran Cheng, Feifei Zhao, Daisy Zhang-Negrerie, Yunfei Du, and Kang Zhao

Organic Letters 2012 Volume 14(Issue 21) pp:5480-5483

Publication Date(Web):October 25, 2012

DOI:10.1021/ol3025583

A direct β-acyloxylation of enamine compounds has been achieved by using iodosobenzene (PhIO) as an oxidant to realize the intermolecular oxidative C(sp2)-O bond formation between enamines and various carboxylic acids, including N-protected amino acids. The transformation tolerates a wide range of functional groups and furnishes a variety of β-acyloxy enamines that can be conveniently converted to oxazole compounds via cyclodehydration.

Synthesis of carbazolones and 3-acetylindoles via oxidative C–N bond formation through PIFA-mediated annulation of 2-aryl enaminones

Co-reporter:Xu Ban, Yan Pan, Yingfu Lin, Songqing Wang, Yunfei Du and Kang Zhao

Organic & Biomolecular Chemistry 2012 vol. 10(Issue 18) pp:3606-3609

Publication Date(Web):15 Mar 2012

DOI:10.1039/C2OB25348H

A series of carbazolone derivatives and 3-acetylindoles have been achieved via PIFA-mediated intramolecular cyclization of 2-aryl enaminones. This process allows the N-moiety on the side-chain to be annulated to the benzene ring via the metal-free oxidative aromatic C–N bond formation.

Synthesis of N-substituted carbazolones from α-iodo enaminones via Pd(0)-catalyzed intramolecular coupling under microwave irradiation

Co-reporter:Xi-Liu Yun, Wen-Ying Bi, Jian-Hui Huang, Yu Liu, Daisy Zhang-Negrerie, Yun-Fei Du, Kang Zhao

Tetrahedron Letters 2012 Volume 53(Issue 38) pp:5076-5080

Publication Date(Web):19 September 2012

DOI:10.1016/j.tetlet.2012.07.009

A variety of N-aryl and N-alkyl carbazolones were conveniently achieved in good to high yields via Pd2(dba)3-mediated intramolecular coupling of N-substituted α-iodo enaminones under microwave irradiation. The Pd(0)-catalyzed cyclization was found to proceed favorably with the more electron-deficient phenyl ring during the reactions involving unsymmetrical N,N-diaryl α-iodo enaminones. This unique property enables the construction of carbazolone skeleton containing nitro substituted benzenoid ring.

Synthesis of Functionalized Fluorescent Indenes from Electron-Rich α-Aryl Ketonitriles

Co-reporter:Le Liu, Yanfeng Fan, Qiaoqiao He, Yun Zhang, Daisy Zhang-Negrerie, Jianhui Huang, Yunfei Du, and Kang Zhao

The Journal of Organic Chemistry 2012 Volume 77(Issue 8) pp:3997-4004

Publication Date(Web):March 28, 2012

DOI:10.1021/jo300367q

A series of functionalized indenes bearing 1,3-dicyano groups were synthesized from electron-rich α-aryl ketonitriles in the presence of K3Fe(CN)6 and NaOAc, possibly through tandem process involving dimerization, heterolytic cleavage of carbon–carbon bond, intermolecular coupling, and the subsequent intramolecular cyclization. The 2-arylindene compounds obtained possess good fluorescent properties.

Synthesis of Oxazoles from Enamides via Phenyliodine Diacetate-Mediated Intramolecular Oxidative Cyclization

Co-reporter:Yunhui Zheng, Xuming Li, Chengfeng Ren, Daisy Zhang-Negrerie, Yunfei Du, and Kang Zhao

The Journal of Organic Chemistry 2012 Volume 77(Issue 22) pp:10353-10361

Publication Date(Web):October 29, 2012

DOI:10.1021/jo302073e

A group of functionalized oxazoles were synthesized in moderate to good yields from enamides via phenyliodine diacetate (PIDA)-mediated intramolecular cyclization. The main advantageous features of the present method include its broad substrate scope and the heavy-metal-free characteristic of the oxidative carbon–oxygen bond formation process.

Oxidative aromatic C–N bond formation: convenient synthesis of N-amino-3-nitrile-indolesviaFeBr3-mediated intramolecular cyclization

Co-reporter:Zisheng Zheng, Lina Tang, Yanfeng Fan, Xiuxiang Qi, Yunfei Du and Daisy Zhang-Negrerie

Organic & Biomolecular Chemistry 2011 vol. 9(Issue 10) pp:3714-3725

Publication Date(Web):02 Mar 2011

DOI:10.1039/C1OB05069A

A variety of functionalized N-amino-3-nitrile-indole derivatives are obtained via an intramolecular hetero-cyclization of 2-aryl-3-substituted hydrazono-alkylnitriles using FeBr3 as a single electron oxidant. This approach allows the N-moiety on the side-chain to be annulated to the benzene ring during the final synthetic step via direct oxidative aromatic C–N bond formation.

Synthesis of 2-(Trifluoromethyl)oxazoles from β-Monosubstituted Enamines via PhI(OCOCF3)2-Mediated Trifluoroacetoxylation and Cyclization

Co-reporter:Feifei Zhao, Xin Liu, Rui Qi, Daisy Zhang-Negrerie, Jianhui Huang, Yunfei Du, and Kang Zhao

The Journal of Organic Chemistry 2011 Volume 76(Issue 24) pp:10338-10344

Publication Date(Web):November 8, 2011

DOI:10.1021/jo202070h

Treatment of β-monosubstituted enamines with phenyliodine bis(trifluoroacetate) (PIFA) was found to give a variety of 4,5-disubstituted 2-(trifluoromethyl)oxazoles. This approach allows the incorporation of the trifluoromethyl moiety in PIFA into the final products, which presumably takes place via the oxidative β-trifluoroacetoxylation of the enamine substrates followed by subsequent intramolecular cyclization.

Synthesis of Coumestan Derivatives via FeCl3-Mediated Oxidative Ring Closure of 4-Hydroxy Coumarins

Co-reporter:Lina Tang, Yongle Pang, Qiao Yan, Liuqing Shi, Jianhui Huang, Yunfei Du, and Kang Zhao

The Journal of Organic Chemistry 2011 Volume 76(Issue 8) pp:2744-2752

Publication Date(Web):March 14, 2011

DOI:10.1021/jo2000644

A concise and efficient approach to the syntheses of coumestan analogues has been developed. The underpinning strategy involves a FeCl3-mediated direct intramolecular oxidative annellation of 4-hydroxy-3-phenyl-2H-chromen-2-one derivatives. Utilizing this synthetic protocol, a variety of coumestan derivatives were conveniently obtained from readily available reagents.

Simple Conversion of Enamines to 2H-Azirines and Their Rearrangements under Thermal Conditions

Co-reporter:Xiaoxun Li, Yunfei Du, Zhidan Liang, Xiangke Li, Yan Pan and Kang Zhao

Organic Letters 2009 Volume 11(Issue 12) pp:2643-2646

Publication Date(Web):May 13, 2009

DOI:10.1021/ol9006663

A variety of substituted enamine derivatives were first found to be conveniently converted to the corresponding 2H-azirines mediated by phenyliodine (III) diacetate (PIDA). The formed 2-aryl-2H-azirines could be applied in the synthesis of indole-3-carbonitriles or isoxazoles via thermal rearrangements.

Oxidative Aromatic C−O Bond Formation: Synthesis of 3-Functionalized Benzo[b]furans by FeCl3-Mediated Ring Closure of α-Aryl Ketones

Co-reporter:Zhidan Liang, Weizhe Hou, Yunfei Du, Yongliang Zhang, Yan Pan, Deng Mao and Kang Zhao

Organic Letters 2009 Volume 11(Issue 21) pp:4978-4981

Publication Date(Web):October 5, 2009

DOI:10.1021/ol902157c

A variety of 3-functionalized benzo[b]furans were achieved by way of a FeCl3-mediated intramolecular cyclization of electron-rich α-aryl ketones. The alkoxy substituent on the benzene ring in the substrates was essential for an efficient cyclization to occur. This novel method allows the construction of benzo[b]furan rings by joining the O-atom on the side chain to the benzene ring via direct oxidative aromatic C−O bond formation.

Organocatalytic amination of alkyl ethers via n-Bu4NI/t-BuOOH-mediated intermolecular oxidative C(sp3)–N bond formation: novel synthesis of hemiaminal ethers

Co-reporter:Longyang Dian, Sisi Wang, Daisy Zhang-Negrerie, Yunfei Du and Kang Zhao

Chemical Communications 2014 - vol. 50(Issue 79) pp:NaN11741-11741

Publication Date(Web):2014/08/13

DOI:10.1039/C4CC05758A

Constructions of tetrahydro-γ-carboline skeletons via intramolecular oxidative carbon–carbon bond formation of enamines

Co-reporter:Jinglei Lv, Ji Li, Daisy Zhang-Negrerie, Siyun Shang, Qingzhi Gao, Yunfei Du and Kang Zhao

Organic & Biomolecular Chemistry 2013 - vol. 11(Issue 12) pp:NaN1932-1932

Publication Date(Web):2013/02/05

DOI:10.1039/C3OB00039G

Synthesis of carbazolones and 3-acetylindoles via oxidative C–N bond formation through PIFA-mediated annulation of 2-aryl enaminones

Co-reporter:Xu Ban, Yan Pan, Yingfu Lin, Songqing Wang, Yunfei Du and Kang Zhao