Hypervalent organoiodine compounds: from reagents to valuable building blocks in synthesis

• Gwendal Grelier,
• Benjamin Darses and
• Philippe Dauban

Beilstein J. Org. Chem. 2018, 14, 1508–1528, doi:10.3762/bjoc.14.128

• , their reactivity is higher than that of the corresponding aryl halides, a property that has been widely exploited to develop efficient transition-metal-catalyzed cross coupling reactions [55]. The latter, however, allow for transferring only one of the two aromatic motifs of the iodonium reagents

• reductive elimination. Starting from the ortho-N-(acyl)diaryl-λ3-iodanes 57, a combination of copper and palladium catalysis, in the presence of a phosphine ligand, induces the internal O-arylation of the proximal amide moiety, followed by a subsequent metal-catalyzed coupling-reaction with the resulting Ar

• -arylation of carbonyl compounds In addition to their role as aryl donors in numerous metal-catalyzed couplings, diaryl-λ3-iodanes are also relevant reagents to perform the α-arylation of enolates. However, the reaction is again limited to the transfer of a single aryl group. As an alternative to address

Metal-free formal synthesis of phenoxazine

• Gabriella Kervefors,
• Antonia Becker,
• Chandan Dey and
• Berit Olofsson

Beilstein J. Org. Chem. 2018, 14, 1491–1497, doi:10.3762/bjoc.14.126

• recently, Bolm and co-workers reported a metal-free cyclization of iodo-substituted diaryl ethers with a broad scope (Scheme 1b) [18]. Transition metal-catalyzed cross couplings have also been employed to form the required C–O and C–N bonds, e.g., by Cu-catalyzed cyclization of 2-(2-bromophenoxy)anilines

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

• organometallics, involving a wide range of transition metal-catalyzed reactions. For example, transmetalation between an organonickel (or organocobalt) complex and chromium salt results in the formation of a highly nucleophilic organochromium species, which enables efficient addition to aldehydes to give

Recent applications of chiral calixarenes in asymmetric catalysis

• Mustafa Durmaz,
• Erkan Halay and
• Selahattin Bozkurt

Beilstein J. Org. Chem. 2018, 14, 1389–1412, doi:10.3762/bjoc.14.117

• reaction. In these reactions, calixarenes are used either as ligands in metal-catalyzed reactions or as organocatalysts. The application of inherently chiral calixarenes as chiral catalysts is still quite scarce, except in aldol, Michael and Henry reactions. Asymmetric catalysis with chiral calixarenes in

Synthesis of chiral 3-substituted 3-amino-2-oxindoles through enantioselective catalytic nucleophilic additions to isatin imines

• Hélène Pellissier

Beilstein J. Org. Chem. 2018, 14, 1349–1369, doi:10.3762/bjoc.14.114

• , ECA109 and BT474 cancer cell lines. Metal-catalyzed reactions In addition to organocatalysts, chiral metal catalysts [41][42][43][44][45][46][47] have been recently applied to promote enantioselective Mannich reactions. As an example, in 2015 Feng et al. reported the enantioselective Mannich reaction of

[3 + 2]-Cycloaddition reaction of sydnones with alkynes

• Veronika Hladíková,
• Jiří Váňa and
• Jiří Hanusek

Beilstein J. Org. Chem. 2018, 14, 1317–1348, doi:10.3762/bjoc.14.113

• by Taran et al. [4]. In order to avoid duplication our review is therefore focused in more detail on thermal, photochemical as well as metal-catalyzed reactions of sydnones with alkynes and factors that influence the yield and ratio of both possible regioisomers and also the kinetics and mechanism of

Atom-economical group-transfer reactions with hypervalent iodine compounds

• Andreas Boelke,
• Peter Finkbeiner and
• Boris J. Nachtsheim

Beilstein J. Org. Chem. 2018, 14, 1263–1280, doi:10.3762/bjoc.14.108

• lead to an overall AE of up to 70% but also produces synthetically versatile intermediates for subsequent transformations, in particular metal-catalyzed cross-coupling reactions. If benziodoxolones or benziodoxoles are used as group-transfer reagents, nearly 100% AE is possible since the counterion

A selective removal of the secondary hydroxy group from ortho-dithioacetal-substituted diarylmethanols

• Anna Czarnecka,
• Emilia Kowalska,
• Agnieszka Bodzioch,
• Joanna Skalik,
• Marek Koprowski,
• Krzysztof Owsianik and
• Piotr Bałczewski

Beilstein J. Org. Chem. 2018, 14, 1229–1237, doi:10.3762/bjoc.14.105

• the key substrates for aromatic cyclodehydration, also known as the Bradsher reaction [15], which leads to fused, polycyclic aromatic hydrocarbons [16][17][18][19]. This type of reaction found applications in synthesis of organic, optoelectronic materials [20][21][22]. Metal-catalyzed cross-coupling

• ) has been performed. It is important for the sulfur-containing substrates for which metal-catalyzed cross-coupling reactions fail. The dibenzylic OH group has been preferentially reduced with the ZnI2/Na(CN)BH3 system in the presence of an ortho-dithioacetal moiety to give ortho-1,3-dithianylaryl(aryl

Rhodium-catalyzed C–H functionalization of heteroarenes using indoleBX hypervalent iodine reagents

• Erwann Grenet,
• Ashis Das,
• Paola Caramenti and
• Jérôme Waser

Beilstein J. Org. Chem. 2018, 14, 1208–1214, doi:10.3762/bjoc.14.102

• ), which ends up on the pyridinone ring. As alternative, a Suzuki–Miyaura coupling between 3-halogenoindoles and (2-methoxypyridyl)boronic acids followed by a deprotection of the methoxy group [7][8] or transition-metal-catalyzed annulation methods [9] have also been reported. In contrast, several

• (III) catalyst for C-5 and C-6 functionalization, respectively [13]. Hypervalent iodine reagents in general [20], and benziodoxole derivatives in particular [21], have found broad application in synthetic chemistry. Aryl iodonium salts have been used successfully in transition-metal-catalyzed

One-pot synthesis of diaryliodonium salts from arenes and aryl iodides with Oxone–sulfuric acid

• Natalia Soldatova,
• Pavel Postnikov,
• Olga Kukurina,
• Viktor V. Zhdankin,
• Akira Yoshimura,
• Thomas Wirth and
• Mekhman S. Yusubov

Beilstein J. Org. Chem. 2018, 14, 849–855, doi:10.3762/bjoc.14.70

• nucleophiles including electron-rich carbon-centered species [5][6][7]. The unique arylating reactivity of diaryliodonium salts has been demonstrated in many metal-catalyzed and also metal-free transformations [8][9][10][11][12][13][14][15]. The development of novel synthetic approaches to diaryliodonium salts

Chlorination of phenylallene derivatives with 1-chloro-1,2-benziodoxol-3-one: synthesis of vicinal-dichlorides and chlorodienes

• Zhensheng Zhao and
• Graham K. Murphy

Beilstein J. Org. Chem. 2018, 14, 796–802, doi:10.3762/bjoc.14.67

• - and vinyl chlorides are highly sought-after intermediates for effecting allylations, and for use in transition metal-catalyzed carbon–carbon and carbon–heteroatom bond-forming reactions [13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28]. Given the versatility of allyl chloride and β

Bromide-assisted chemoselective Heck reaction of 3-bromoindazoles under high-speed ball-milling conditions: synthesis of axitinib

• Jingbo Yu,
• Zikun Hong,
• Xinjie Yang,
• Yu Jiang,
• Zhijiang Jiang and
• Weike Su

Beilstein J. Org. Chem. 2018, 14, 786–795, doi:10.3762/bjoc.14.66

• transition-metal-catalyzed reactions [1][2], which has shown itself as a powerful synthetic tool in both academic and industrial practice [3][4][5][6][7]. The transformation has been enrolled as key steps for numerous synthetic routes, including the recent President Green Chemistry Award winner route of

• interesting substrates for industrial applications [11][12], possessing the characteristics of lower cost, easier to obtain and stable to store, they face the problem of dehalogenations especially under metal-catalyzed reactions [8][13][14][15][16][17][18], affecting the reaction yield and selectivity

Cobalt-catalyzed directed C–H alkenylation of pivalophenone N–H imine with alkenyl phosphates

• Wengang Xu and
• Naohiko Yoshikai

Beilstein J. Org. Chem. 2018, 14, 709–715, doi:10.3762/bjoc.14.60

• alkenylation reaction of pivalophenone N–H imine with an alkenyl phosphate. The reaction tolerates various substituted pivalophenone N–H imines as well as cyclic and acyclic alkenyl phosphates. Keywords: alkenylation; C–C bond formation; C–H activation; cobalt; imine; Introduction Transition-metal-catalyzed

Palladium-catalyzed ortho-halogenations of acetanilides with N-halosuccinimides via direct sp² C–H bond activation in ball mills

• Zi Liu,
• Hui Xu and
• Guan-Wu Wang

Beilstein J. Org. Chem. 2018, 14, 430–435, doi:10.3762/bjoc.14.31

• construction of C–X bonds. With the development of transition-metal-catalyzed cross-coupling reactions, a series of halogenations at the ortho-position of the directing groups have been disclosed [5][6][7][8][9][10][11][12][13][14][15][16][17][18]. Nevertheless, from the viewpoint of green chemistry, the

One-pot preparation of 4-aryl-3-bromocoumarins from 4-aryl-2-propynoic acids with diaryliodonium salts, TBAB, and Na₂S₂O₈

• Teppei Sasaki,
• Katsuhiko Moriyama and
• Hideo Togo

Beilstein J. Org. Chem. 2018, 14, 345–353, doi:10.3762/bjoc.14.22

• -ketoesters and phenols (the Pechmann condensation) [17]. Recent studies for the metal-catalyzed reactions for the synthesis of the coumarin skeleton are as follows: the Yb(OTf)3-catalyzed microwave irradiation of phenols and propynoic acids [18], the Pd(OAc)2-catalyzed oxidative cyclocarbonylation of 2

Photocatalytic formation of carbon–sulfur bonds

• Alexander Wimmer and
• Burkhard König

Beilstein J. Org. Chem. 2018, 14, 54–83, doi:10.3762/bjoc.14.4

• –S bonds were developed and already excellently reviewed, including nucleophilic substitution reactions between S-nucleophiles and organic electrophiles, metal-catalyzed C–S bond formations and organocatalytic or enzymatic approaches [15][16][18][20][21][22]. This review provides a brief overview

Ring-size-selective construction of fluorine-containing carbocycles via intramolecular iodoarylation of 1,1-difluoro-1-alkenes

• Takeshi Fujita,
• Ryo Kinoshita,
• Tsuyoshi Takanohashi,
• Naoto Suzuki and
• Junji Ichikawa

Beilstein J. Org. Chem. 2017, 13, 2682–2689, doi:10.3762/bjoc.13.266

• synthesis. We have already achieved the metal-catalyzed and acid-mediated cationic cyclization of 1,1-difluoro-1-alkenes. In the former case, we reported the palladium [6][7][8][9][10], indium [10][11][12][13], and silver-catalyzed construction of ring-fluorinated carbocycles and heterocycles [14]. In the

Comparative profiling of well-defined copper reagents and precursors for the trifluoromethylation of aryl iodides

• Peter T. Kaplan,
• Jessica A. Lloyd,
• Mason T. Chin and
• David A. Vicic

Beilstein J. Org. Chem. 2017, 13, 2297–2303, doi:10.3762/bjoc.13.225

• bear the trifluoromethyl group have great importance in the life sciences and materials fields as well as discovery chemistry in general [1][2][3]. Consequently, transition-metal-catalyzed methods for preparing aromatic trifluoromethyl compounds from readily available aryl halides are an area that has

Synthesis of substituted Z-styrenes by Hiyama-type coupling of oxasilacycloalkenes: application to the synthesis of a 1-benzoxocane

• James R. Vyvyan,
• Courtney A. Engles,
• Scott L. Bray,
• Erik D. Wold,
• Christopher L. Porter and
• Mikhail O. Konev

Beilstein J. Org. Chem. 2017, 13, 2122–2127, doi:10.3762/bjoc.13.209

• ; palladium; silicon; Introduction The development of transition metal-catalyzed cross-coupling technologies over the last four decades revolutionized the synthetic chemistry. Indeed, the importance of Pd-catalyzed coupling was recognized with the 2010 Nobel Prize awarded to Heck, Negishi and Suzuki [1][2

Difunctionalization of alkenes with iodine and tert-butyl hydroperoxide (TBHP) at room temperature for the synthesis of 1-(tert-butylperoxy)-2-iodoethanes

• Hao Wang,
• Cui Chen,
• Weibing Liu and
• Zhibo Zhu

Beilstein J. Org. Chem. 2017, 13, 2023–2027, doi:10.3762/bjoc.13.200

• starting materials in a single operation [1][2][3][4][5][6]. Traditional studies have mainly focused on transition-metal-catalyzed direct vicinal difunctionalization of alkenes by installing two substituents across the C=C double bond to form two new bonds or two new functional groups [7][8][9], such as

Transition-metal-free synthesis of 3-sulfenylated chromones via KIO₃-catalyzed radical C(sp²)–H sulfenylation

• Yanhui Guo,
• Shanshan Zhong,
• Li Wei and
• Jie-Ping Wan

Beilstein J. Org. Chem. 2017, 13, 2017–2022, doi:10.3762/bjoc.13.199

• . Presently, the most popular approaches in constructing a C(sp2)–S bond are the transition-metal-catalyzed Ullmann C–S coupling reaction [4][5][6][7][8], Chan–Lam cross-coupling reaction [9][10][11][12] as well as the transition-metal-catalyzed C–H bond activation [13][14][15]. Recently, as a new trend, the

Solvent-free and room temperature synthesis of 3-arylquinolines from different anilines and styrene oxide in the presence of Al₂O₃/MeSO₃H

• Hashem Sharghi,
• Mahdi Aberi,
• Mohsen Khataminejad and
• Pezhman Shiri

Beilstein J. Org. Chem. 2017, 13, 1977–1981, doi:10.3762/bjoc.13.193

• ]. Transition metal-catalyzed processes [5][6][7][8] and metal-free paths [9][10][11] are two general approaches for the synthesis of this type of compounds. However, the existing methods suffer from complicated multistep processes, limited availability of substrates, toxic organic solvents, long reaction times

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

• ]. Advantageously this methodology was applicable for both solid and liquid olefins. Mechanochemical C–H functionalization Transition-metal-catalyzed activation and functionalization of inert C–H bonds of organic molecules provides a broad avenue in the synthesis of wide range of compounds. In 2015, Bolm and co

Synthesis of benzothiophene and indole derivatives through metal-free propargyl–allene rearrangement and allyl migration

• Jinzhong Yao,
• Yajie Xie,
• Lianpeng Zhang,
• Yujin Li and
• Hongwei Zhou

Beilstein J. Org. Chem. 2017, 13, 1866–1870, doi:10.3762/bjoc.13.181

• (Figure 1) [7][8][9]. Moreover, benzothiophenes have extensive applications in materials science. Besides the traditional methods of transition metal-catalyzed cyclization of alkyne substrates [10][11][12], the synthesis of benzothiophenes via metal-free conditions has recently aroused much attention [13

Mechanochemical synthesis of thioureas, ureas and guanidines

• Vjekoslav Štrukil

Beilstein J. Org. Chem. 2017, 13, 1828–1849, doi:10.3762/bjoc.13.178

• the molecules presented herein testify that mechanochemistry can be utilized to successfully cope with the challenges of modern synthetic organic chemistry, in terms of quantitative conversion of chiral substrates, desymmetrization of small molecules, metal-catalyzed reactions and molecular