Copper-catalyzed asymmetric sp³ C–H arylation of tetrahydroisoquinoline mediated by a visible light photoredox catalyst

• Pierre Querard,
• Inna Perepichka,
• Eli Zysman-Colman and
• Chao-Jun Li

Beilstein J. Org. Chem. 2016, 12, 2636–2643, doi:10.3762/bjoc.12.260

• providing extremely important tools for potential transition-metal-catalyzed enantioselective reactions of sp3 C–H bonds, which could be carried out at low temperature and under mild reaction conditions [13][14]. We envisioned that combining photoredox catalysis with typical cross-coupling methods will

Rapid regio- and multi-coupling reactivity of 2,3-dibromobenzofurans with atom-economic triarylbismuths under palladium catalysis

• Maddali L. N. Rao,
• Jalindar B. Talode and
• Venneti N. Murty

Beilstein J. Org. Chem. 2016, 12, 2065–2076, doi:10.3762/bjoc.12.195

• ambipolar materials (CZBDF, Figure 1c) [16]. To note, synthetic functionalization under transition-metal-catalyzed conditions allows the preparation of multi-substituted benzofurans in a facile manner [23][24][25][26][27][28]. Langer et al. reported the site-selective Suzuki–Miyaura reaction of 2,3

Unusual reactions of diazocarbonyl compounds with α,β-unsaturated δ-amino esters: Rh(II)-catalyzed Wolff rearrangement and oxidative cleavage of N–H-insertion products

• Valerij A. Nikolaev,
• Jury J. Medvedev,
• Olesia S. Galkina,
• Ksenia V. Azarova and
• Christoph Schneider

Beilstein J. Org. Chem. 2016, 12, 1904–1910, doi:10.3762/bjoc.12.180

• ; transition-metal-catalyzed reactions; Wolff rearrangement; Introduction Transition-metal-catalyzed reactions of diazocarbonyl compounds (DCC) with different organic substrates comprise a powerful tool of organic synthesis [1][2][3][4][5][6][7][8]. Of prime importance was found to be the ability of reactive

• bonds in the structure of α-aminocarbonyl compounds is also a well-known transition-metal-catalyzed process, which gives rise to the occurrence of formamides and carboxylic acids [26][29]. In this case the system O2/TEMPO is used as a catalyst for the cleavage process, but the reaction also proceeds

On the cause of low thermal stability of ethyl halodiazoacetates

• Magnus Mortén,
• Martin Hennum and
• Tore Bonge-Hansen

Beilstein J. Org. Chem. 2016, 12, 1590–1597, doi:10.3762/bjoc.12.155

• transition metal-catalyzed reactions [5]. A large number of diazo esters have been synthesized and an order has been arranged for α-substituents that increase the stability of the diazoesters [3]. Halogen substituents are completely absent from this list of α-substituents. Hence, the relative position of

One-pot synthesis of 4′-alkyl-4-cyanobiaryls on the basis of the terephthalonitrile dianion and neutral aromatic nitrile cross-coupling

• Roman Yu. Peshkov,
• Elena V. Panteleeva,
• Wang Chunyan,
• Evgeny V. Tretyakov and
• Vitalij D. Shteingarts

Beilstein J. Org. Chem. 2016, 12, 1577–1584, doi:10.3762/bjoc.12.153

• acylation–reduction–halogenation–cyanodehalogenation (Scheme 1) [15], are currently being replaced with methods based on transition-metal-catalyzed biaryl cross-coupling [16][17][18][19][20][21]. This methodology is well developed, compatible with different substituents in the substrate and opens up a new

Synthesis of 2-substituted tetraphenylenes via transition-metal-catalyzed derivatization of tetraphenylene

• Shulei Pan,
• Hang Jiang,
• Yanghui Zhang,
• Yu Zhang and
• Dushen Chen

Beilstein J. Org. Chem. 2016, 12, 1302–1308, doi:10.3762/bjoc.12.122

• tetraphenylenes through a transition-metal-catalyzed derivatization has been developed. Three types of functionalities, including OAc, X (Cl, Br, I) and carbonyl, were introduced onto tetraphenylene, which allows the easy access to a variety of monosubstituted tetraphenylenes. These reactions could accelerate

• ][29][30][31][32][33][34][35][36][37][38][39][40][41][42]. While most of these traditional approaches suffer from harsh conditions or complicated procedures, a novel strategy via transition-metal-catalyzed C–H activation has attracted great attention and emerged as a powerful methodology for the

• transition-metal-catalyzed derivatization of tetraphenylene, which provide a new method for the synthesis of 2-substituted tetraphenylenes. Results and Discussion The acetoxy group is an important functional group because it can be transformed into a variety of other functionalities [46][47], thus making the

Conjugate addition–enantioselective protonation reactions

• James P. Phelan and
• Jonathan A. Ellman

Beilstein J. Org. Chem. 2016, 12, 1203–1228, doi:10.3762/bjoc.12.116

• tert-butyl ester was the reactivity significantly impacted (R2 = n-Pr, R3 = t-Bu, 36% yield, 98:2 er). Transition metals A handful of research groups have investigated transition metal-catalyzed conjugate addition–enantioselective protonation sequences involving α,β-unsaturated esters. A common theme

• this context, Reetz and co-workers were the first to report the transition metal-catalyzed enantioselective addition of arylboronic acids to an α-substituted-α,β-unsaturated ester to provide enantioenriched phenylalanine derivatives 48a (Scheme 10) [29]. Notably, a BINAP-derived rhodium(I) catalyst was

• , protodemetalation liberates the product and regenerates 69. While the overall process provides the same product as a conjugate addition–enantioselective protonation sequence, mechanistically this, along with other transition metal-catalyzed reactions that invoke a conjugate addition–enantioselective protonation

Synthesis of highly functionalized 2,2'-bipyridines by cyclocondensation of β-ketoenamides – scope and limitations

• Paul Hommes and
• Hans-Ulrich Reissig

Beilstein J. Org. Chem. 2016, 12, 1170–1177, doi:10.3762/bjoc.12.112

• substituent in moderate to good overall yields. This functional group fixes the tautomeric structure and makes the products less polar which allowed smooth isolation, purification and identification. An additional advantage of this substituent is its ability to allow transition-metal-catalyzed coupling

• prepared by the methods described above are excellent and versatile precursors for transition-metal-catalyzed coupling reactions [32][53][54][55][56][57]. Standard conditions for a Suzuki coupling smoothly transform compound 5a and a boronic acid derivative into the expected 4-tolyl-substituted derivative

Chiral cyclopentadienylruthenium sulfoxide catalysts for asymmetric redox bicycloisomerization

• Barry M. Trost,
• Michael C. Ryan and
• Meera Rao

Beilstein J. Org. Chem. 2016, 12, 1136–1152, doi:10.3762/bjoc.12.110

• ], medicinal targets [2], and materials [3], organic chemists have made the construction of cyclic, organic molecules one of the most important areas of research in their discipline. Of the available methods to affect cyclization, transition metal-catalyzed enyne cycloisomerizations [4] have been recognized as

Iodine-mediated synthesis of 3-acylbenzothiadiazine 1,1-dioxides

• Long-Yi Xi,
• Ruo-Yi Zhang,
• Lei Shi,
• Shan-Yong Chen and
• Xiao-Qi Yu

Beilstein J. Org. Chem. 2016, 12, 1072–1078, doi:10.3762/bjoc.12.101

• reaction conditions, causing the formation of byproducts. An alternative route to the benzothiadiazine 1,1-dioxide ring are transition metal-catalyzed reactions. Various benzothiadiazine 1,1-dioxides were successfully prepared using this approach [16][17][18][19]. However, the separation of transitional

Cationic Pd(II)-catalyzed C–H activation/cross-coupling reactions at room temperature: synthetic and mechanistic studies

• Takashi Nishikata,
• Alexander R. Abela,
• Shenlin Huang and
• Bruce H. Lipshutz

Beilstein J. Org. Chem. 2016, 12, 1040–1064, doi:10.3762/bjoc.12.99

• intermediate, characterized by X-ray analysis. Roles of various additives in the stepwise process have also been studied. Keywords: arylation; cationic palladium; C–H functionalization; green chemistry; olefination; Introduction Transition metal-catalyzed, direct functionalization of aryl C–H bonds has made

Catalytic asymmetric synthesis of biologically important 3-hydroxyoxindoles: an update

• Bin Yu,
• Hui Xing,
• De-Quan Yu and
• Hong-Min Liu

Beilstein J. Org. Chem. 2016, 12, 1000–1039, doi:10.3762/bjoc.12.98

• metal-catalyzed synthesis The chiral ligand/metal complexes have been widely employed in catalytic asymmetric synthesis of enantioenriched 3-hydroxyoxindoles, achieving good to excellent enantioselectivities and high yields. Pd-catalyzed allylation of isatins The palladium catalyst is widely used in

• are covered. Besides, recent progress on the 3-hydroxyoxindole-based further transformations are covered in this review. Perspectives and future directions are also discussed based on previous reports and our own understandings. This review is organized based on the catalyst types. Review Transition

A modular approach to neutral P,N-ligands: synthesis and coordination chemistry

• Vladislav Vasilenko,
• Torsten Roth,
• Clemens K. Blasius,
• Sebastian N. Intorp,
• Hubert Wadepohl and
• Lutz H. Gade

Beilstein J. Org. Chem. 2016, 12, 846–853, doi:10.3762/bjoc.12.83

• : 2.270 Å to 2.305 Å for the P–Ir bond and 2.109 Å to 2.136 Å for the N–Ir bond). Similarly, no major structural changes of the ligand backbone were detected for the different oxidation states. Furthermore, due to the importance of palladium in common transition-metal-catalyzed transformations [21], we

Recent advances in C(sp³)–H bond functionalization via metal–carbene insertions

• Bo Wang,
• Di Qiu,
• Yan Zhang and
• Jianbo Wang

Beilstein J. Org. Chem. 2016, 12, 796–804, doi:10.3762/bjoc.12.78

• be focused on the development of novel catalysts as well as the perceptive combination of catalyst/substrates in order to achieve highly selective C(sp3)–H bond insertions. The structure of TpM catalysts. Structure of TpM-type catalysts. Pathway for transition-metal-catalyzed carbene insertion into C

Opportunities and challenges for direct C–H functionalization of piperazines

• Zhishi Ye,
• Kristen E. Gettys and
• Mingji Dai

Beilstein J. Org. Chem. 2016, 12, 702–715, doi:10.3762/bjoc.12.70

• pharmaceuticals. Herein we summarize the current synthetic methods available to perform C–H functionalization on piperazines in order to lend structural diversity to this privileged drug scaffold. Multiple approaches such as those involving α-lithiation trapping, transition-metal-catalyzed α-C–H

• . Transition-metal-catalyzed α-C–H functionalization Transition-metal-catalyzed direct sp3 C–H bond functionalization at the α-carbon of both cyclic and acyclic amines have been a fertile research field [45][46][47]. In the case of saturated N-heterocycles however, most of the efforts have been focused on

• directed α-C–H functionalization of pyrrolidines and piperidines [48][49][50]. Little progress has been made in transition-metal-catalyzed α-C–H functionalization of piperazines presumably due to the low reactivity and the undesired competitive pathways caused by the addition of the second nitrogen in the

Copper-mediated arylation with arylboronic acids: Facile and modular synthesis of triarylmethanes

• H. Surya Prakash Rao and
• A. Veera Bhadra Rao

Beilstein J. Org. Chem. 2016, 12, 496–504, doi:10.3762/bjoc.12.49

• towards transition metal-catalyzed cross-couplings [43][44][45][46][47][48] or CH arylation followed by an arylative desulfonation [49][50]. The coupling reactions provide an opportunity to install an unactivated aryl group on a carbon bearing two more aryl groups to synthesize the triarylmethane motif

Study on the synthesis of the cyclopenta[f]indole core of raputindole A

• Nils Marsch,
• Mario Kock and
• Thomas Lindel

Beilstein J. Org. Chem. 2016, 12, 334–342, doi:10.3762/bjoc.12.36

• presence of Boc-protected indole nitrogens an acid-catalyzed Meyer–Schuster rearrangement was dismissed. Instead, a transition metal-catalyzed rearrangement employing 1 mol % of MoO2(acac)2/[Au(PPh3)Cl]/AgOTf [37] afforded the α,β-unsaturated ketone 8 as a 2:1 mixture of E/Z isomers (86%), which could not

• the terminal alkyne 18 (97%). Magnesiation (iPrMgCl, THF) and reaction with ketone 6 afforded the benzyloxy-substituted bisindole 21. Transition metal-catalyzed Meyer–Schuster rearrangement afforded 24 (56%, E/Z mixture as above) albeit the catalyst loading had to be increased from 1 to 10 mol %, when

Spiro-fused carbohydrate oxazoline ligands: Synthesis and application as enantio-discrimination agents in asymmetric allylic alkylation

• Jochen Kraft,
• Martin Golkowski and
• Thomas Ziegler

Beilstein J. Org. Chem. 2016, 12, 166–171, doi:10.3762/bjoc.12.18

• of tertiary carbon stereocenters, remains an ongoing challenge. Over the last decades though, transition metal-catalyzed reactions like the asymmetric allylic alkylation (Tsuji–Trost reaction) have evolved into one of the more powerful tools for synthesizing such tertiary stereocenters [7][8]. As a

Versatile deprotonated NHC: C,N-bridged dinuclear iridium and rhodium complexes

• Albert Poater

Beilstein J. Org. Chem. 2016, 12, 117–124, doi:10.3762/bjoc.12.13

• bulky N-substituents [1]. However the existence of stable NHCs was before postulated by Wanzlick et al. during the 1960s [2][3][4] and supported later by Öfele [5][6]. NHCs have become useful ligands in many transition metal-catalyzed reactions, stimulating the study of the unique features of the M–NHC

Recent advances in copper-catalyzed asymmetric coupling reactions

• Fengtao Zhou and
• Qian Cai

Beilstein J. Org. Chem. 2015, 11, 2600–2615, doi:10.3762/bjoc.11.280

• ). Copper-catalyzed couplings of allylic halides with nucleophiles Transition metal-catalyzed allylic substitutions are the most important process for carbon–carbon and carbon–heteroatom bond formation in organic synthesis [56][57][58]. Allylic substitution of the substrate with nucleophiles can afford two

• spirobilactams through a double N-arylation reaction. Asymmetric N-arylation through kinetic resolution. Formation of cyano-substituted quaternary stereocenters through kinetic resolution. Copper-catalyzed intramolecular desymmetric aryl C–O coupling. Transition metal-catalyzed allylic substitutions. Copper

• primary allyl chlorides to react with alkylborane (alkyl-9-BBN) for the generation of a quaternary carbon stereogenic center bearing three sp3-alkyl groups and a vinyl group with an ee up to 90% (Scheme 29). Cu-catalyzed enantioselective allylic substitutions with Grignard reagents Transition metal

Synthesis of Xenia diterpenoids and related metabolites isolated from marine organisms

• Tatjana Huber,
• Lara Weisheit and
• Thomas Magauer

Beilstein J. Org. Chem. 2015, 11, 2521–2539, doi:10.3762/bjoc.11.273

• . Different strategies for the construction of E- or Z-cyclononenes have been reported to date and common reactions are summarized in Scheme 3. Transition metal-catalyzed ([M] = Ru, Mo, W) ring-closing metathesis (RCM) reactions of 1,10-dienes A can be employed for the synthesis of cyclononenes. The E/Z

• , several strategies for the preparation of the characteristic nine-membered carbocyclic ring structures have been developed. The synthetic strategies are typically based on ring expansion (Grob-type fragmentation and sigmatropic rearrangements), ring closing (metathesis and transition metal-catalyzed

Recent developments in copper-catalyzed radical alkylations of electron-rich π-systems

• Kirk W. Shimkin and
• Donald A. Watson

Beilstein J. Org. Chem. 2015, 11, 2278–2288, doi:10.3762/bjoc.11.248

• example of a transition metal-catalyzed cross coupling of tertiary alkyl halides. These types of reactions are often very difficult because of the propensity of the intermediate tertiary alkylmetal to undergo β-hydrogen elimination [33][34][35]. By developing a reaction that proceeds via tertiary alkyl

Recent advances in copper-catalyzed C–H bond amidation

• Jie-Ping Wan and
• Yanfeng Jing

Beilstein J. Org. Chem. 2015, 11, 2209–2222, doi:10.3762/bjoc.11.240

• preferably transformed over secondary C–H bonds (Scheme 9). C(sp2)–H bond amidation The direct transformation of C(sp2)–H bonds constitutes an issue of extensive current interest. On the basis of the pioneering work in transition-metal-catalyzed activation of the C(Ar)–H bonds of electron deficient

C–H bond halogenation catalyzed or mediated by copper: an overview

• Wenyan Hao and
• Yunyun Liu

Beilstein J. Org. Chem. 2015, 11, 2132–2144, doi:10.3762/bjoc.11.230

• , harsh reaction conditions and/or restricted product diversity remain as challenges for these methods. The transition metal-catalyzed C–H functionalization has recently gained considerable attention in the preparation of numerous organic molecules [12][13][14][15][16][17][18]. In this context

• electrophilic substitution reaction, the occurrence of powerful new synthetic strategies such as transition metal-catalyzed C–H activation brought new opportunities to the synthesis of more diversely halogenated products by enabling the halogenation of more challenging substrates by more selective

Copper-mediated synthesis of N-alkenyl-α,β-unsaturated nitrones and their conversion to tri- and tetrasubstituted pyridines

• Dimitra Kontokosta,
• Daniel S. Mueller,
• Dong-Liang Mo,
• Wiktoria H. Pace,
• Rachel A. Simpson and
• Laura L. Anderson

Beilstein J. Org. Chem. 2015, 11, 2097–2104, doi:10.3762/bjoc.11.226

• ][38], fragment couplings [39][40][41][42], and transition metal-catalyzed C–H bond functionalization of α,β-unsaturated imines and oximes [43][44][45][46][47][48][49][50]. We were inspired by the copper-catalyzed coupling of protected α,β-unsaturated oximes and alkenylboronic acids developed by

• corresponding tri- and tetrasubstituted pyridines 9 (Scheme 2C). This use of α,β-unsaturated oxime reagents for the synthesis of pyridines is unique from transition metal-catalyzed C–H bond functionalization processes that require a regioselective migratory insertion. This route is appealing due to the