Synthesis of aryl sulfides via radical–radical cross coupling of electron-rich arenes using visible light photoredox catalysis

• Amrita Das,
• Mitasree Maity,
• Simon Malcherek,
• Burkhard König and
• Julia Rehbein

Beilstein J. Org. Chem. 2018, 14, 2520–2528, doi:10.3762/bjoc.14.228

• reports on direct C–H functionalization using transition metals or metal free [37][38][39] conditions and different sources of sulfur, for example arylsulfonyl chlorides, sodium arylsulfinates, sulfinic acids and arylsulfonyl hydrazides have been reported (Scheme 1). However, the protocols require

Cobalt- and rhodium-catalyzed carboxylation using carbon dioxide as the C1 source

• Tetsuaki Fujihara and
• Yasushi Tsuji

Beilstein J. Org. Chem. 2018, 14, 2435–2460, doi:10.3762/bjoc.14.221

• the carbon–metal bond formation when transition metals are used as the catalyst. In addition, the choice of suitable reducing agents is also crucial for realizing effective carboxylation reactions. In this review, the Co- and Rh-catalyzed transformations of CO2 via C–C bond-forming reactions are

A challenging redox neutral Cp*Co(III)-catalysed alkylation of acetanilides with 3-buten-2-one: synthesis and key insights into the mechanism through DFT calculations

• Andrew Kenny,
• Alba Pisarello,
• Arron Bird,
• Paula G. Chirila,
• Alex Hamilton and
• Christopher J. Whiteoak

Beilstein J. Org. Chem. 2018, 14, 2366–2374, doi:10.3762/bjoc.14.212

• -established palladium-catalysed cross-coupling protocols [4]. Whilst second and third row transition metals are well applied in cross-coupling protocols through C–H activation under mild conditions [5], the drive to use first row metals continues to provide an exciting challenge [6]. The interest in the

• application of these first-row transition metals stems from their low cost, ready availability and often wider reactivity profiles. One particular example which is currently attracting significant interest is cobalt, a metal which has found many applications in C–H functionalisation through exploitation of

Hydroarylations by cobalt-catalyzed C–H activation

• Rajagopal Santhoshkumar and
• Chien-Hong Cheng

Beilstein J. Org. Chem. 2018, 14, 2266–2288, doi:10.3762/bjoc.14.202

• less expensive and more environmentally benign, have attracted significant attention in recent years [16][17][18][19][20][21][22][23][24][25][26][27]. As a member of the first-row transition metals, cobalt complexes are known to be extensively involved in homogeneous catalysis, in particular, C–H

• traditional synthetic methods to construct new C−C bonds. Among the first-row transition metals, both low- and high-valent cobalt catalysts have played a substantial role in these hydroarylation reactions providing an economical alternative to the precious metal-catalyzed reactions and also showed distinct

Coordination-driven self-assembly of discrete Ru₆–Pt₆ prismatic cages

• Aderonke Ajibola Adeyemo and
• Partha Sarathi Mukherjee

Beilstein J. Org. Chem. 2018, 14, 2242–2249, doi:10.3762/bjoc.14.199

• donors and transition metals as electron-deficient acceptors. Diverse functionalities embedded in these homometallic architectures have found useful applications in chemical sensing [24][25][26][27][28][29][30][31][32][33][34][35], catalysis [11][36][37][38][39][40][41][42][43][44][45][46], drug delivery

Applications of organocatalysed visible-light photoredox reactions for medicinal chemistry

• Michael K. Bogdos,
• Emmanuel Pinard and
• John A. Murphy

Beilstein J. Org. Chem. 2018, 14, 2035–2064, doi:10.3762/bjoc.14.179

• pharmaceutical industry. This type of chemistry has also demonstrated a high degree of sustainability, especially when organic dyes can be employed in place of often toxic and environmentally damaging transition metals. The sections are arranged according to the general class of the presented reactions and the

Recent advances in hypervalent iodine(III)-catalyzed functionalization of alkenes

• Xiang Li,
• Pinhong Chen and
• Guosheng Liu

Beilstein J. Org. Chem. 2018, 14, 1813–1825, doi:10.3762/bjoc.14.154

• ) reagents were applied to oxidize transition metals [21][22][23][24][25]. In an alternative way, the electrophilic hypervalent iodine(III) reagents can activate alkenes directly in a metal-free manner. Based on this strategy, dichlorination [26], 1,2-difluorination [27], gem-difluorination [28

Synthesis of spirocyclic scaffolds using hypervalent iodine reagents

• Fateh V. Singh,
• Priyanka B. Kole,
• Saeesh R. Mangaonkar and
• Samata E. Shetgaonkar

Beilstein J. Org. Chem. 2018, 14, 1778–1805, doi:10.3762/bjoc.14.152

• [17]. There are several ways available in literature for the synthesis of spirocyclic compounds but most of them are associated either with transition metals or hypervalent iodine reagents [1][2][3]. Hypervalent iodine reagents provide various functional group transformation opportunities in organic

β-Hydroxy sulfides and their syntheses

• Mokgethwa B. Marakalala,
• Edwin M. Mmutlane and
• Henok H. Kinfe

Beilstein J. Org. Chem. 2018, 14, 1668–1692, doi:10.3762/bjoc.14.143

• not require the use of transition metals. However, the need for stoichiometric amount of the KI promoter (2 equivalents of KI is required relative to a diaryl disulfide substrate) calls for the development of new alternative catalytic methodologies. 3.4 Thiofunctionalization of unactivated alkenes A

Thiocarbonyl-enabled ferrocene C–H nitrogenation by cobalt(III) catalysis: thermal and mechanochemical

• Santhivardhana Reddy Yetra,
• Zhigao Shen,
• Hui Wang and
• Lutz Ackermann

Beilstein J. Org. Chem. 2018, 14, 1546–1553, doi:10.3762/bjoc.14.131

• manifold. Keywords: amidation; C–H activation; cobalt; ferrocene; mechanochemistry; Introduction C–H activation has surfaced as a transformative tool in molecular sciences [1][2][3][4][5][6][7][8][9]. While major advances have been accomplished with precious 4d transition metals, recent focus has shifted

Recent advances in phosphorescent platinum complexes for organic light-emitting diodes

• Cristina Cebrián and
• Matteo Mauro

Beilstein J. Org. Chem. 2018, 14, 1459–1481, doi:10.3762/bjoc.14.124

• ][30]. Apart from the strong σ-donor ability, the great interest for these ligands relies on the robustness that they confer to the resulting complexes, upon coordination onto both early [31] and late transition metals [32][33]. In this regard, the group of Chi employed carbene-based chelates as

Three-component coupling of aryl iodides, allenes, and aldehydes catalyzed by a Co/Cr-hybrid catalyst

• Kimihiro Komeyama,
• Shunsuke Sakiyama,
• Kento Iwashita,
• Itaru Osaka and
• Ken Takaki

Beilstein J. Org. Chem. 2018, 14, 1413–1420, doi:10.3762/bjoc.14.118

• organolithium, organomagnesium, organozinc, and organochromium A, to facilitate addition reactions of appropriate carbon electrophiles such as aldehydes (Scheme 1, top) [1]. In contrast, π-electrophilic carbon-connected late transition metals B facilitate the carbometalation of carbon–carbon multiple bonds

A survey of chiral hypervalent iodine reagents in asymmetric synthesis

• Soumen Ghosh,
• Suman Pradhan and
• Indranil Chatterjee

Beilstein J. Org. Chem. 2018, 14, 1244–1262, doi:10.3762/bjoc.14.107

• environmentally friendly, mild and economic reagents have been used in catalytic or stoichiometric amounts as an alternative to transition metals for delivering enantioenriched molecules. Varieties of different chiral reagents and their use for demanding asymmetric transformations have been documented over the

• application due to their reduced toxicity, ready availability and lower costs as replacement for transition metals leading to several “metal-free” like chemical transformations. The ongoing demand of modern synthetic chemistry for the development of catalytic enantioselective C–C bond formation reactions

• for carbonyl α-functionalizations are still considered as highly demandable in synthetic organic chemistry. In this regard transition metals have been successfully applied and even allow accomplishing such transformations asymmetrically. On the other hand, diaryliodonium salts are known to transfer

Imide arylation with aryl(TMP)iodonium tosylates

• Souradeep Basu,
• Alexander H. Sandtorv and
• David R. Stuart

Beilstein J. Org. Chem. 2018, 14, 1034–1038, doi:10.3762/bjoc.14.90

• , transition metals feature prominently in such methods, but even recent examples employ stoichiometric metal mediators [4]. Metal-free methods by classic SNAr are also attractive, but only possible on very electron-deficient arene substrates [5]. Diaryliodonium salts are useful reagents for metal-free aryl

Mechanochemistry of nucleosides, nucleotides and related materials

• Olga Eguaogie,
• Joseph S. Vyle,
• Patrick F. Conlon,
• Manuela A. Gîlea and
• Yipei Liang

Beilstein J. Org. Chem. 2018, 14, 955–970, doi:10.3762/bjoc.14.81

• presence of L-tartaric after grinding the racemate [112]. Heinicke briefly summarised early investigations into potential prebiotic α-amino acid preparation under “tribochemical stress” in the presence of transition metals [113] and more recently, Hernández and co-workers demonstrated that an efficient

• , consideration of primordial nucleoside and nucleotide mechanochemistry has been much more limited with greater focus upon precursor mechanosynthesis under high-energy plasma conditions [116][117] or extra-terrestrial delivery of concentrated transition metals [118]. In this general context, although Orgel and

Nanoreactors for green catalysis

• M. Teresa De Martino,
• Loai K. E. A. Abdelmohsen,
• Floris P. J. T. Rutjes and
• Jan C. M. van Hest

Beilstein J. Org. Chem. 2018, 14, 716–733, doi:10.3762/bjoc.14.61

• used and the usage of transition metals. Finding an approach to utilize chiral catalysts in water while minimizing their cost (i.e., recycling) is still a big challenge. In order to accomplish this, various strategies have been proposed and applied [17][18][19]. One significant, well-established and

Functionalization of N-arylglycine esters: electrocatalytic access to C–C bonds mediated by n-Bu₄NI

• Mi-Hai Luo,
• Yang-Ye Jiang,
• Kun Xu,
• Yong-Guo Liu,
• Bao-Guo Sun and
• Cheng-Chu Zeng

Beilstein J. Org. Chem. 2018, 14, 499–505, doi:10.3762/bjoc.14.35

• efficient electrocatalytic cross dehydrogenative coupling of arylglycine esters with C–H nucleophiles has been developed. This protocol employs simple n-Bu4NI as the redox catalyst, avoiding utilization of transition metals and excess amounts of external oxidant, thereby providing an environmentally benign

Transition-metal-free [3 + 3] annulation of indol-2-ylmethyl carbanions to nitroarenes. A novel synthesis of indolo[3,2-b]quinolines (quindolines)

• Michał Nowacki and
• Krzysztof Wojciechowski

Beilstein J. Org. Chem. 2018, 14, 194–202, doi:10.3762/bjoc.14.14

• formation of prerequisite reagents or for ultimate steps of the synthesis resulting in the formation of the indolo[3,2-b]quinoline framework [14][16][17][18]. These procedures may require meticulous removal of traces of transition metals, particularly if the product is intended to use in biomedical or

• developed a simple synthesis of indolo[3,2-b]quinoline derivatives by the reaction of nitroarenes with indol-2-ylmethyl carbanions generated from easily accessible starting materials. The reactions proceed under mild conditions and the elaborated method does not employ transition metals at any stage thus

Progress in copper-catalyzed trifluoromethylation

• Guan-bao Li,
• Chao Zhang,
• Chun Song and
• Yu-dao Ma

Beilstein J. Org. Chem. 2018, 14, 155–181, doi:10.3762/bjoc.14.11

• trifluoromethanes. Conclusion In the past few years, the field of copper-mediated trifluoromethylation of aromatic and aliphatic compounds including heterocycles have experienced significant advances. In parallel with this field, the trifluoromethylation catalyzed by other transition metals like Pd, Ag, Fe and

Main group mechanochemistry

• Agota A. Gečiauskaitė and
• Felipe García

Beilstein J. Org. Chem. 2017, 13, 2068–2077, doi:10.3762/bjoc.13.204

• produce the desired Ar-BIAN ligands 2 and 3, respectively, in good yields (see Scheme 4). Here, mechanochemistry bypasses the use of templating agent transition metals, shortening the synthetic route and reducing its environmental impact. Their respective indium(III) BIAN complexes 4 and 5 were also

Mechanochemical synthesis of small organic molecules

• Tapas Kumar Achar,
• Anima Bose and
• Prasenjit Mal

Beilstein J. Org. Chem. 2017, 13, 1907–1931, doi:10.3762/bjoc.13.186

• transition metals, could be performed in shorter reaction time and uses stable dichalcogenides rather than toxic thiols and selenols. Organometallic synthesis and catalytic application Mechano-synthesis of organometallic compounds The last decade has witnessed a rapid growth of mechanochemistry in organic

An effective Pd nanocatalyst in aqueous media: stilbene synthesis by Mizoroki–Heck coupling reaction under microwave irradiation

• Carolina S. García,
• Paula M. Uberman and
• Sandra E. Martín

Beilstein J. Org. Chem. 2017, 13, 1717–1727, doi:10.3762/bjoc.13.166

• (NPs) of transition metals have been introduced as eco-catalysts in several reactions [20]. The NPs became a useful tool for catalytic transformations due to their excellent performance, which is related to their small size and a high surface-to-volume ratio [21][22][23][24][25]. Moreover, they are

Oxidative dehydrogenation of C–C and C–N bonds: A convenient approach to access diverse (dihydro)heteroaromatic compounds

• Santanu Hati,
• Ulrike Holzgrabe and
• Subhabrata Sen

Beilstein J. Org. Chem. 2017, 13, 1670–1692, doi:10.3762/bjoc.13.162

• with the tert-butoxide radical to generate I. I then undergoes an intramolecular cyclization to form J, followed by aromatization to afford the desired compounds. Transition metal-induced oxidative dehydrogenation Since the applications of various transition metals as catalysts in C–N, C–O and C–C bond

• facilitate the conversion [52][53][54][55]. Unfortunately most of these methods suffer from the disadvantages of prolonged reaction time, poor yield and competing oxidative dealkylation of 4-benzyl and sec-alkyl-substituted DHP substrates. Alternative strategies involving transition metals and microwave

Phenylsilane as an effective desulfinylation reagent

• Wanda H. Midura,
• Aneta Rzewnicka and
• Jerzy A. Krysiak

Beilstein J. Org. Chem. 2017, 13, 1513–1517, doi:10.3762/bjoc.13.150

• methodology [10][11][12][13][14]. Besides the well-known metal-catalyzed hydrosilylation, transition metals in the presence of Brønsted or Lewis acids were used for the reduction. Recently base-activated silanes were also used for this purpose [15][16][17]. Results and Discussion Our recent investigations

Construction of highly enantioenriched spirocyclopentaneoxindoles containing four consecutive stereocenters via thiourea-catalyzed asymmetric Michael–Henry cascade reactions

• Yonglei Du,
• Jian Li,
• Kerong Chen,
• Chenglin Wu,
• Yu Zhou and
• Hong Liu

Beilstein J. Org. Chem. 2017, 13, 1342–1349, doi:10.3762/bjoc.13.131

• strategies with chiral transition metals [27][28][29][30][31][32][33], organocatalysts such as secondary amines [34][35][36], nucleophilic phosphines [26][37][38][39][40][41][42][43][44], tertiary amines [45], N-heterocyclic carbenes (NHCs) [46][47][48], and cinchona alkaloid derivatives [25][28][49][50