Congyang Wang

Transition-metal-catalyzed intra- and intermolecular annulation reactions have been widely investigated, owing to their important applications in the synthesis of natural products, pharmaceuticals, and functional materials. Rhenium lies at the interface of early and late transition metals in the Periodic Table, with its unique properties, such as low electronegativity and ability to activate C–H and C–C bonds, enabling a series of atom- and step-economical annulation reactions from simple substrates. This Microreview aims to summarize the impressive progress in rhenium-catalyzed annulation reactions in recent years from our own viewpoints and perspectives.

Manganese-Catalyzed ortho-CH Alkenylation of Aromatic NH Imidates with Alkynes: Versatile Access to Mono-Alkenylated Aromatic Nitriles

Co-reporter:Xiaoxu Yang;Xiqing Jin

Advanced Synthesis & Catalysis 2016 Volume 358( Issue 15) pp:2436-2442

Publication Date(Web):

DOI:10.1002/adsc.201600128

Copper-catalyzed three-component cascade reaction of alkynes, sulfonyl azides and simple aldehydes/ketones

Co-reporter:Yuanyuan Hu, Bingwei Zhou and Congyang Wang

Organic & Biomolecular Chemistry 2016 vol. 14(Issue 11) pp:3022-3026

Publication Date(Web):16 Feb 2016

DOI:10.1039/C6OB00146G

A copper-catalyzed dimethylzinc-promoted three-component cascade reaction of alkynes, sulfonyl azides, and simple aldehydes or ketones is described. Polysubstituted olefins were thus constructed expeditiously in a one-pot procedure under mild conditions.

Manganese-catalyzed bicyclic annulations of imines and α,β-unsaturated esters via C−H activation

Co-reporter:Yuanyuan Hu

Science China Chemistry 2016 Volume 59( Issue 10) pp:1301-1305

Publication Date(Web):2016 October

DOI:10.1007/s11426-016-0164-8

A manganese-catalyzed bicyclic annulation of imines with α,β-unsaturated esters via C–H activation is described, which provides an expedient access to fused β-lactams in one-step operation with high efficiency and good functional group tolerance. Of note, both ketimines and aldimines are amenable to this transformation. Mechanistic studies have identified a five-membered azamanganacycle as the key reaction intermediate.

Rhenium-Catalyzed [4 + 1] Annulation of Azobenzenes and Aldehydes via Isolable Cyclic Rhenium(I) Complexes

Co-reporter:Xiaoyu Geng and Congyang Wang

Organic Letters 2015 Volume 17(Issue 10) pp:2434-2437

Publication Date(Web):May 6, 2015

DOI:10.1021/acs.orglett.5b00938

The first Re-catalyzed [4 + 1] annulation of azobenzenes with aldehydes was developed to furnish 2H-indazoles via isolable and characterized cyclic ReI-complexes. For the first time, the acetate-acceleration effect is showcased in Re-catalyzed C–H activation reactions. Remarkably, mechanistic studies revealed an irreversible aldehyde-insertion step, which is in sharp contrast to those of previous Rh- and Co-systems.

Rhenium-catalyzed C–H aminocarbonylation of azobenzenes with isocyanates

Co-reporter:Xiaoyu Geng and Congyang Wang

Organic & Biomolecular Chemistry 2015 vol. 13(Issue 28) pp:7619-7623

Publication Date(Web):09 Jun 2015

DOI:10.1039/C5OB01121C

The first C–H aminocarbonylation of azobenzenes with isocyanates is achieved by using rhenium-catalysis, which provides an expedient and atom-economical access to varied o-azobenzamides from readily available starting materials. The reaction efficiency can be enhanced by the catalytic use of sodium acetate via accelerated C–H bond activation.

Rhenium-catalyzed dehydrogenative olefination of C(sp3)–H bonds with hypervalent iodine(III) reagents

Co-reporter:Haidong Gu and Congyang Wang

Organic & Biomolecular Chemistry 2015 vol. 13(Issue 21) pp:5880-5884

Publication Date(Web):20 Apr 2015

DOI:10.1039/C5OB00619H

A dehydrogenative olefination of C(sp3)–H bonds is disclosed here, by merging rhenium catalysis with an alanine-derived hypervalent iodine(III) reagent. Thus, cyclic and acyclic ethers, toluene derivatives, cycloalkanes, and nitriles are all successfully alkenylated in a regio- and stereoselective manner.

Direct silylation reactions of inert C-H bonds via transition metal catalysis

Co-reporter:Yunhui Yang

Science China Chemistry 2015 Volume 58( Issue 8) pp:1266-1279

Publication Date(Web):2015 August

DOI:10.1007/s11426-015-5375-0

In the past thirty years, transition metal catalyzed silylation of inert C-H bonds has attracted intensive attention due to the importance and wide use of organosilicon compounds. In this review, the silylation reactions of inert C-H bonds catalyzed by transition metal complexes of Ir, Rh, Ru, Pt, Pd, Ni, and Sc, and the strategies utilized to access the site-selective C-H silylation products have been summarized. Furthermore, the mechanisms of C-H silylation reactions have been discussed briefly.

Manganese-Catalyzed Direct Nucleophilic C(sp2)H Addition to Aldehydes and Nitriles

Co-reporter:Dr. Bingwei Zhou;Yuanyuan Hu ;Dr. Congyang Wang

Angewandte Chemie International Edition 2015 Volume 54( Issue 46) pp:13659-13663

Publication Date(Web):

DOI:10.1002/anie.201506187

Abstract

Herein, a manganese-catalyzed nucleophilic addition of inert C(sp²)H bonds to aldehydes and nitriles is disclosed by virtue of a dual activation strategy. The reactions feature mild reaction conditions, excellent regio- and stereoselectivity, and a wide substrate scope, which includes both aromatic and olefinic CH bonds, as well as a large variety of aldehydes and nitriles. Moreover, mechanistic studies shed light on possible catalytic cycles.

Inside Back Cover: Manganese-Catalyzed Direct Nucleophilic C(sp2)H Addition to Aldehydes and Nitriles (Angew. Chem. Int. Ed. 46/2015)

Co-reporter:Dr. Bingwei Zhou;Yuanyuan Hu ;Dr. Congyang Wang

Angewandte Chemie International Edition 2015 Volume 54( Issue 46) pp:

Publication Date(Web):

DOI:10.1002/anie.201508487

Manganese-Catalyzed Direct Nucleophilic C(sp2)H Addition to Aldehydes and Nitriles

Co-reporter:Dr. Bingwei Zhou;Yuanyuan Hu ;Dr. Congyang Wang

Angewandte Chemie 2015 Volume 127( Issue 46) pp:13863-13867

Publication Date(Web):

DOI:10.1002/ange.201506187

Abstract

Innenrcktitelbild: Manganese-Catalyzed Direct Nucleophilic C(sp2)H Addition to Aldehydes and Nitriles (Angew. Chem. 46/2015)

Co-reporter:Dr. Bingwei Zhou;Yuanyuan Hu ;Dr. Congyang Wang

Angewandte Chemie 2015 Volume 127( Issue 46) pp:

Publication Date(Web):

DOI:10.1002/ange.201508487

Mn-Catalyzed Three-Component Reactions of Imines/Nitriles, Grignard Reagents, and Tetrahydrofuran: An Expedient Access to 1,5-Amino/Keto Alcohols

Co-reporter:Ruoyu He ; Xiqing Jin ; Hui Chen ; Zhi-Tang Huang ; Qi-Yu Zheng

Journal of the American Chemical Society 2014 Volume 136(Issue 18) pp:6558-6561

Publication Date(Web):April 22, 2014

DOI:10.1021/ja503520t

An expedient Mn-catalyzed three-component synthesis of 1,5-amino/keto alcohols from Grignard reagents, imines/nitriles, and tetrahydrofuran (THF) is described, which deviates from the classic Grignard addition to imines/nitriles in THF solvent. THF is split and “sewn” in an unprecedented manner in the reaction, leading to the formation of two geminal C–C bonds via C–H and C–O cleavage. Mechanistic experiments and DFT calculations reveal radical and organo-Mn intermediates in the catalytic cycle and the α-arylative ring-opening of THF as the key reaction step.

Origins of Selective C(sp2)–H Activation Using Transition Metal Complexes with N,N-Bidentate Directing Groups: A Combined Theoretical–Experimental Study

Co-reporter:Hao Tang, Bingwei Zhou, Xu-Ri Huang, Congyang Wang, Jiannian Yao, and Hui Chen

ACS Catalysis 2014 Volume 4(Issue 2) pp:649

Publication Date(Web):January 13, 2014

DOI:10.1021/cs401141k

The strategy using N,N-bidentate directing groups is a promising way to achieve selective C(sp2)–H activation inaccessible by that of monodentate directing groups. Herein, through theoretical calculations, we present a rationale behind this strategy, which deciphers its key roles in C–H activation promoted by Ni, Pd, Ru, and Cu. The calculations reveal two key points: (a) Between the two coordination sites of the N,N-bidentate directing group, the proximal one influences more the C–H activation barrier ΔG‡, whereas the distal site affects more the free energy change ΔG relevant to the substrate coordination. (b) Enlarging/shrinking the chelation ring can exert different effects on the reactivity, depending on the metal identity and the ring size. Importantly, our computational results are in full agreement with previous experimental findings concerning reactivity. Furthermore, a prediction about the unprecedented reactivity from our theory is confirmed by our experiments, lending more credence to the rationale and insights gained in this study.Keywords: C(sp2)−H activation; coordination free energy; density functional theory; N,N-bidentate directing group; reaction barrier; transition metal

Amine-accelerated manganese-catalyzed aromatic C–H conjugate addition to α,β-unsaturated carbonyls

Co-reporter:Bingwei Zhou, Pengchen Ma, Hui Chen and Congyang Wang

Chemical Communications 2014 vol. 50(Issue 93) pp:14558-14561

Publication Date(Web):06 Oct 2014

DOI:10.1039/C4CC07598F

Since 1987, the stoichiometric two-step C–H conjugate addition reactions have been developed. Herein we describe the first manganese-catalyzed one-step direct aromatic C–H conjugate addition to α,β-unsaturated carbonyls, which is accelerated by a catalytic amount of dicyclohexylamine. Experimental and computational studies substantiated the validity of the proposed catalytic cycle.

Isoquinoline skeleton synthesis via chelation-assisted C−H activation

Co-reporter:Ruoyu He, Zhi-Tang Huang, Qi-Yu Zheng, Congyang Wang

Tetrahedron Letters 2014 Volume 55(Issue 42) pp:5705-5713

Publication Date(Web):15 October 2014

DOI:10.1016/j.tetlet.2014.08.077

Transition-metal-catalyzed isoquinoline synthesis that profits from the strategy of chelation-assisted C−H activation has flourished over the past decade. By virtue of the directed C−H bond cleavage of imines, amines, amidines, oximes, hydroximoyl halides, hydrazones, or azines, diverse isoquinoline derivatives have been accessed from alkynes, conjugated dienes, or diazo compounds under the catalysis of rhodium, ruthenium, palladium, nickel, or manganese. This digest summarizes the annulation reactions via chelation-assisted C−H activation leading to isoquinolines, isoquinolinium salts, or isoquinoline N-oxides.Figure optionsDownload full-size imageDownload as PowerPoint slide

Manganese-Catalyzed Dehydrogenative [4+2] Annulation of NH Imines and Alkynes by CH/NH Activation

Co-reporter:Ruoyu He;Dr. Zhi-Tang Huang;Dr. Qi-Yu Zheng ;Dr. Congyang Wang

Angewandte Chemie 2014 Volume 126( Issue 19) pp:5050-5053

Publication Date(Web):

DOI:10.1002/ange.201402575

Abstract

Described herein is a manganese-catalyzed dehydrogenative [4+2] annulation of NH imines and alkynes, a reaction providing highly atom-economical access to diverse isoquinolines. This transformation represents the first example of manganese-catalyzed CH activation of imines; the stoichiometric variant of the cyclomanganation was reported in 1971. The redox neutral reaction produces H₂ as the major byproduct and eliminates the need for any oxidants, external ligands, or additives, thus standing out from known isoquinoline synthesis by transition-metal-catalyzed CH activation. Mechanistic studies revealed the five-membered manganacycle and manganese hydride species as key reaction intermediates in the catalytic cycle.

Manganese-Catalyzed Dehydrogenative [4+2] Annulation of NH Imines and Alkynes by CH/NH Activation

Co-reporter:Ruoyu He;Dr. Zhi-Tang Huang;Dr. Qi-Yu Zheng ;Dr. Congyang Wang

Angewandte Chemie International Edition 2014 Volume 53( Issue 19) pp:4950-4953

Publication Date(Web):

DOI:10.1002/anie.201402575

Abstract

Re/Mg Bimetallic Tandem Catalysis for [4+2] Annulation of Benzamides and Alkynes via C-H/N-H Functionalization

Co-reporter:Qiuzheng Tang ; Dexin Xia ; Xiqing Jin ; Qing Zhang ; Xiao-Qiang Sun

Journal of the American Chemical Society 2013 Volume 135(Issue 12) pp:4628-4631

Publication Date(Web):March 7, 2013

DOI:10.1021/ja400020e

A rhenium-magnesium cocatalyzed [4+2] annulation of benzamides and alkynes via C-H/N-H functionalization is described. The reaction features a divergent and high level of diastereoselectivities, which are readily switchable by subtle tuning of reaction conditions. Thus, a wide range of both cis- and trans-3,4-dihydroisoquinolinones is expediently synthesized in a highly atom-economical manner. Moreover, mechanistic studies unraveled a tandem mode of action between rhenium and magnesium in the catalytic cycles.

Mn-Catalyzed Aromatic C–H Alkenylation with Terminal Alkynes

Co-reporter:Bingwei Zhou ; Hui Chen

Journal of the American Chemical Society 2013 Volume 135(Issue 4) pp:1264-1267

Publication Date(Web):January 3, 2013

DOI:10.1021/ja311689k

The first manganese-catalyzed aromatic C–H alkenylation with terminal alkynes is described. The procedure features an operationally simple catalyst system containing commercially available MnBr(CO)5 and dicyclohexylamine (Cy2NH). The reaction occurs readily in a highly chemo-, regio-, and stereoselective manner delivering anti-Markovnikov E-configured olefins in high yields. Experimental study and DFT calculations reveal that (1) the reaction is initiated by a C–H activation step via the cooperation of manganese and base; (2) manganacycle and alkynylmanganese species are the key reaction intermediates; and (3) the ligand-to-ligand H-transfer and alkynyl-assisted C–H activation are the key steps rendering the reaction catalytic in manganese.

Alkene Oxyalkylation Enabled by Merging Rhenium Catalysis with Hypervalent Iodine(III) Reagents via Decarboxylation

Co-reporter:Yin Wang ; Lei Zhang ; Yunhui Yang ; Ping Zhang ; Zhenting Du

Journal of the American Chemical Society 2013 Volume 135(Issue 48) pp:18048-18051

Publication Date(Web):November 17, 2013

DOI:10.1021/ja410195j

Rhenium-catalyzed oxyalkylation of alkenes is described, where hypervalent iodine(III) reagents derived from widely occurring aliphatic carboxylic acids were used as, for the first time, not only an oxygenation source but also an alkylation source via decarboxylation. The reaction also features a wide substrate scope, totally regiospecific difunctionalization, mild reaction conditions, and ready availability of both substrates. Mechanistic studies revealed a decarboxylation/radical-addition/cation-trapping cascade operating in the reaction.

Rhenium-Catalyzed Regiodivergent Addition of Indoles to Terminal Alkynes

Co-reporter:Dexin Xia, Yin Wang, Zhenting Du, Qi-Yu Zheng, and Congyang Wang

Organic Letters 2012 Volume 14(Issue 2) pp:588-591

Publication Date(Web):December 29, 2011

DOI:10.1021/ol203199m

An efficient rhenium-catalyzed site-switchable addition of indoles to terminal alkynes is described. A variety of bisindolylalkane derivatives are expeditiously synthesized in high yields with excellent regioselectivity. Preliminary mechanistic study sheds light on the observed regiodivergent addition.

Palladium-Catalyzed Intermolecular Decarboxylative Coupling of 2-Phenylbenzoic Acids with Alkynes via C−H and C−C Bond Activation

Co-reporter:Congyang Wang ; Souvik Rakshit ;Frank Glorius

Journal of the American Chemical Society () pp:

Publication Date(Web):

DOI:10.1021/ja106130r

A novel protocol for palladium-catalyzed intermolecular formal [4 + 2] annulation of 2-phenylbenzoic acids with alkynes is described. Acridine is shown to be essential for the high reaction efficiency. Phenanthrene derivatives are formed in moderate to good yields without coupling (pseudo)halides or organometallic species.

Rhenium and base co-catalyzed [3 + 2] annulations of N–H ketimines and alkynes to access unprotected tertiary indenamines through C–H bond activation

Co-reporter:Xiqing Jin, Xiaoxu Yang, Yunhui Yang and Congyang Wang

Inorganic Chemistry Frontiers 2016 - vol. 3(Issue 2) pp:NaN272-272

Publication Date(Web):2015/12/24

DOI:10.1039/C5QO00336A

Herein, a rhenium-catalyzed [3 + 2] carbocyclization of N–H ketimines and alkynes through C–H bond activation to afford unprotected tertiary indenamines is described. Notably, the catalytic use of a cheap base, sodium carbonate, was demonstrated to be crucial to the success of this reaction. The protocol is also highlighted by a high atom-economy, a broad substrate scope, and excellent regioselectivity for unsymmetrical alkynes.

Rhenium-catalyzed C–H aminocarbonylation of azobenzenes with isocyanates

Co-reporter:Xiaoyu Geng and Congyang Wang

Organic & Biomolecular Chemistry 2015 - vol. 13(Issue 28) pp:NaN7623-7623

Publication Date(Web):2015/06/09

DOI:10.1039/C5OB01121C

Copper-catalyzed three-component cascade reaction of alkynes, sulfonyl azides and simple aldehydes/ketones

Co-reporter:Yuanyuan Hu, Bingwei Zhou and Congyang Wang

Organic & Biomolecular Chemistry 2016 - vol. 14(Issue 11) pp:NaN3026-3026

Publication Date(Web):2016/02/16

DOI:10.1039/C6OB00146G

Amine-accelerated manganese-catalyzed aromatic C–H conjugate addition to α,β-unsaturated carbonyls

Co-reporter:Bingwei Zhou, Pengchen Ma, Hui Chen and Congyang Wang