Recent advances in transition-metal-free arylation reactions involving hypervalent iodine salts

• Ritu Mamgain,
• Kokila Sakthivel and
• Fateh V. Singh

Beilstein J. Org. Chem. 2024, 20, 2891–2920, doi:10.3762/bjoc.20.243

• bis(4-methoxyphenyl)iodonium diacetate (70) or ArI(OH)OTs highly regioselective gemfibrozil methyl ester derived iodonium salts 71 were obtained in moderate to good yield. These salts were then used for various modifications like alkynylation, arylation, esterification, etherification, fluorination

Copper-catalyzed yne-allylic substitutions: concept and recent developments

• Shuang Yang and
• Xinqiang Fang

Beilstein J. Org. Chem. 2024, 20, 2739–2775, doi:10.3762/bjoc.20.232

• precise and highly regioselective construction of an array of novel chiral coumarin derivatives, characterized by their exceptional synthetic efficiency and remarkable tolerance towards a broad spectrum of functional groups (Scheme 21, 22a–n). Almost at the same time, Lin et al. [71] also devised a copper

Facile preparation of fluorine-containing 2,3-epoxypropanoates and their epoxy ring-opening reactions with various nucleophiles

• Yutaro Miyashita,
• Sae Someya,
• Tomoko Kawasaki-Takasuka,
• Tomohiro Agou and
• Takashi Yamazaki

Beilstein J. Org. Chem. 2024, 20, 2421–2433, doi:10.3762/bjoc.20.206

• failed in this transformation and recovery of 2b was observed (Table 2, entry 10). As was pointed out in the introductory section, the highly regioselective epoxy ring opening is well compared with the case when the nonfluorinated substrate (Ph instead of CF3 in 2b) was employed [25][26]. With the

Regioselective alkylation of a versatile indazole: Electrophile scope and mechanistic insights from density functional theory calculations

• Pengcheng Lu,
• Luis Juarez,
• Paul A. Wiget,
• Weihe Zhang,
• Krishnan Raman and
• Pravin L. Kotian

Beilstein J. Org. Chem. 2024, 20, 1940–1954, doi:10.3762/bjoc.20.170

• character of TsO− and triphenylphosphine oxide, precluding any thermodynamic versus kinetic arguments for regioselectivity. Conclusion We have established highly regioselective N1- and N2-alkylations of methyl 5-bromo-1H-indazole-3-carboxylate from diverse commercially available alcohols with excellent

Advancements in hydrochlorination of alkenes

• Daniel S. Müller

Beilstein J. Org. Chem. 2024, 20, 787–814, doi:10.3762/bjoc.20.72

• Syntheses [83]. The proposed catalytic cycle is shown in Figure 7 and involves the following steps. First, a cobalt hydride complex A is formed in situ from Co(II) complex and the silane. Then, regioselective alkene hydrocobaltation takes place. This step is highly regioselective, placing the cobalt atom on

N-Boc-α-diazo glutarimide as efficient reagent for assembling N-heterocycle-glutarimide diads via Rh(II)-catalyzed N–H insertion reaction

• Grigory Kantin,
• Pavel Golubev,
• Alexander Sapegin,
• Alexander Bunev and
• Dmitry Dar’in

Beilstein J. Org. Chem. 2023, 19, 1841–1848, doi:10.3762/bjoc.19.136

• also highly regioselective, proceeding via attack on the 2-N atom to give products 6m–o. In the instance of unsubstituted benzotriazole, a minor regioisomer 6m' was identified with a calculated yield of 6% using NMR data. Benzotriazoles featuring electron-withdrawing substituents showed incomplete

Recent advancements in iodide/phosphine-mediated photoredox radical reactions

• Tinglan Liu,
• Yu Zhou,
• Junhong Tang and
• Chengming Wang

Beilstein J. Org. Chem. 2023, 19, 1785–1803, doi:10.3762/bjoc.19.131

• construction of these scaffolds [28][29][30][31], and one of the most efficient approaches is the cascade cyclization strategy [29][30][31]. Xu, Li, Wei and their co-workers successfully devised a series of highly regioselective iodide/phosphine synergistically catalyzed photocatalytic cascade annulations for

Morpholine-mediated defluorinative cycloaddition of gem-difluoroalkenes and organic azides

• Tzu-Yu Huang,
• Mario Djugovski,
• Sweta Adhikari,
• Destinee L. Manning and
• Sudeshna Roy

Beilstein J. Org. Chem. 2023, 19, 1545–1554, doi:10.3762/bjoc.19.111

• ] cycloaddition reaction utilizing gem-difluoroalkenes, which inherently exhibit attenuated activity compared to the activated α-CF3 carbonyls. This report provides a highly regioselective and novel way to access C-4-morpholine-functionalized fully decorated 1,2,3-triazoles from gem-difluoroalkenes and organic

Transition-metal-catalyzed domino reactions of strained bicyclic alkenes

• Austin Pounder,
• Eric Neufeld,
• Peter Myler and
• William Tam

Beilstein J. Org. Chem. 2023, 19, 487–540, doi:10.3762/bjoc.19.38

• ) and O-benzoylhydroxylamine derivatives 54 (Scheme 9) [43]. While the scope of bicyclic alkenes was quite extensive with aza-, carbo-, and oxabicyclic alkenes being amenable to the reaction, electron-deficient substrates resulted in lowered yields. Of note, the reaction is highly regioselective with

Thiophene/selenophene-based S-shaped double helicenes: regioselective synthesis and structures

• Mengjie Wang,
• Lanping Dang,
• Wan Xu,
• Zhiying Ma,
• Liuliu Shao,
• Guangxia Wang,
• Chunli Li and
• Hua Wang

Beilstein J. Org. Chem. 2022, 18, 809–817, doi:10.3762/bjoc.18.81

• , and double oxidative photocyclization. The photocyclization was a highly regioselective process. The molecular structures of DH-1 and DH-2 were confirmed by X-ray single-crystal analysis. Multiple intermolecular interactions, such as C–S, C–Se, S–S, S–Se, and Se–Se, were observed in the crystal

A study on selective transformation of norbornadiene into fluorinated cyclopentane-fused isoxazolines

• Zsanett Benke,
• Attila M. Remete and
• Loránd Kiss

Beilstein J. Org. Chem. 2021, 17, 2051–2066, doi:10.3762/bjoc.17.132

• catalyst provided mostly monocoupled (±)-25a, but a low amount of (±)-25c was also isolated. Note, that the CM reaction was highly regioselective (alternative monocoupled product (±)-25b was not detected). Conclusion An insight into the study of selective functionalization of norbornadiene through nitrile

Recent advances in the syntheses of anthracene derivatives

• Giovanni S. Baviera and
• Paulo M. Donate

Beilstein J. Org. Chem. 2021, 17, 2028–2050, doi:10.3762/bjoc.17.131

• activation In 2009, Liang et al. reported an efficient and highly regioselective route to construct substituted tetracyclic benz[a]anthracene derivatives 115 (Scheme 26) [60]. For this purpose, the authors developed an efficient palladium-catalyzed tandem C–H activation/bis-cyclization reaction of

Synthesis of β-triazolylenones via metal-free desulfonylative alkylation of N-tosyl-1,2,3-triazoles

• Soumyaranjan Pati,
• Renata G. Almeida,
• Eufrânio N. da Silva Júnior and
• Irishi N. N. Namboothiri

Beilstein J. Org. Chem. 2021, 17, 762–770, doi:10.3762/bjoc.17.66

• formation of an unexpected product, i.e., β-triazolylenone. Being inspired by the results, we intended to use 1,3-dicarbonyl compounds as detosylative alkylating agents that would lead to the formation of β-triazolylenones in a highly regioselective manner under mild conditions (Scheme 1d). Results and

• with cyclic 1,3-diketones to form various β-triazolylenones. Although the scope of the 1,3-dicarbonyl compound is limited, the protocol is very convenient and useful as it employs very mild reaction conditions. It is also highly regioselective and `affords only N1-alkylated products in moderate to

CF₃-substituted carbocations: underexploited intermediates with great potential in modern synthetic chemistry

• Anthony J. Fernandes,
• Armen Panossian,
• Bastien Michelet,
• Agnès Martin-Mingot,
• Frédéric R. Leroux and
• Sébastien Thibaudeau

Beilstein J. Org. Chem. 2021, 17, 343–378, doi:10.3762/bjoc.17.32

• amines 178a–c, the corresponding hemiaminal ethers 179a–c were obtained (Scheme 43). The reaction is highly regioselective as no methoxylation of 178a and 178b was observed on the nontrifluoromethylated alkyl substituent (Me or Et). Hence, although amines 178a–c are more difficult to oxidize than their

The preparation and properties of 1,1-difluorocyclopropane derivatives

• Kymbat S. Adekenova,
• Peter B. Wyatt and
• Sergazy M. Adekenov

Beilstein J. Org. Chem. 2021, 17, 245–272, doi:10.3762/bjoc.17.25

• -difluoro-1-alkenylcyclopropanes 90–92 (Scheme 41) [88]. All three compounds underwent a highly regioselective cleavage of the C1–C3 bond. Hence, the major products of all rearrangements were produced via [1,3]-sigmatropic shifts (Scheme 41). The products were the result of the breaking of the C–C bond

Stereoselective Biginelli-like reaction catalyzed by a chiral phosphoric acid bearing two hydroxy groups

• Xiaoyun Hu,
• Jianxin Guo,
• Cui Wang,
• Rui Zhang and
• Victor Borovkov

Beilstein J. Org. Chem. 2020, 16, 1875–1880, doi:10.3762/bjoc.16.155

• To develop new efficient stereoselective catalysts for Biginelli-like reactions, a chiral phosphoric acid bearing two hydroxy groups derived from ʟ-tartaric acid was successfully synthesized via highly regioselective transformations of enantiopure 1,1,4,4-tetraphenylbutanetetraol. The obtained

• followed by further modifications involving highly regioselective 1,4-cycloetherization [19], 2,3-spiroboration [20], 2,3-sulfitation [21], and 2,3-methylation [22] of 1. Therefore, the strategy for the catalyst’s preparation was based on the established regioselective 2,3-sulfitation reaction of 1 and

• hydroxy groups in 3 for this reaction, the methylated derivative 7 was synthesized (Scheme 2). As shown in Scheme 2, first (2R,3R)-1 was subjected to highly regioselective 2,3-dimethylation [23] with NaH/MeI to give product (2R,3R)-6. Then the corresponding dimethylated chiral phosphoric acid 7 was

When metal-catalyzed C–H functionalization meets visible-light photocatalysis

• Lucas Guillemard and
• Joanna Wencel-Delord

Beilstein J. Org. Chem. 2020, 16, 1754–1804, doi:10.3762/bjoc.16.147

• activation of one substrate, and a two-electron activation by a transition-metal catalyst of the other. The main advantage of such a system is to promote highly regioselective reactions. Indeed, while radical transformations generally suffer from selectivity issues, interception of radicals by metal

Photocatalyzed syntheses of phenanthrenes and their aza-analogues. A review

• Alessandra Del Tito,
• Havall Othman Abdulla,
• Davide Ravelli,
• Stefano Protti and
• Maurizio Fagnoni

Beilstein J. Org. Chem. 2020, 16, 1476–1488, doi:10.3762/bjoc.16.123

• highly regioselective strategy for the synthesis of a library of polyheteroaromatic compounds under photocatalytic conditions was reported (Scheme 13). The process made use of fac-Ir(ppy)3 (0.3 mol %) as the photoredox catalyst and occurred at room temperature under extremely mild conditions. The

Synthesis of 3-substituted isoxazolidin-4-ols using hydroboration–oxidation reactions of 4,5-unsubstituted 2,3-dihydroisoxazoles

• Lívia Dikošová,
• Júlia Laceková,
• Ondrej Záborský and
• Róbert Fischer

Beilstein J. Org. Chem. 2020, 16, 1313–1319, doi:10.3762/bjoc.16.112

• hydroborations were highly regioselective, leading only to the formation of isoxazolidines with the hydroxy group in the C-4 position. From a stereochemical point of view, the additions took place with an excellent trans selectivity with respect to the substituent at C-3. A sequential oxidation/reduction route

Recent applications of porphyrins as photocatalysts in organic synthesis: batch and continuous flow approaches

• Rodrigo Costa e Silva,
• Luely Oliveira da Silva,
• Aloisio de Andrade Bartolomeu,
• Timothy John Brocksom and
• Kleber Thiago de Oliveira

Beilstein J. Org. Chem. 2020, 16, 917–955, doi:10.3762/bjoc.16.83

• highly regioselective photoinduced hydro-defluorination of perfluoroarenes with RhIII(TSPP) [38]. The oxidative addition of the perfluoroarene to the metal complex furnished the active rhodium aryl complex intermediate, which led to the product after visible light irradiation. The hydro-defluorination

Room-temperature Pd/Ag direct arylation enabled by a radical pathway

• Amy L. Mayhugh and
• Christine K. Luscombe

Beilstein J. Org. Chem. 2020, 16, 384–390, doi:10.3762/bjoc.16.36

• -growth polymerization mechanism. Generically, a small molecule reaction is a candidate for adaptation to a polymerization when it is highly regioselective, and high yielding. Under step-growth conditions a high yielding reaction is essential for producing a high molecular weight material [8], which

Recent advances on the transition-metal-catalyzed synthesis of imidazopyridines: an updated coverage

• Gagandeep Kour Reen,
• Ashok Kumar and
• Pratibha Sharma

Beilstein J. Org. Chem. 2019, 15, 1612–1704, doi:10.3762/bjoc.15.165

Steroid diversification by multicomponent reactions

• Leslie Reguera,
• Cecilia I. Attorresi,
• Javier A. Ramírez and
• Daniel G. Rivera

Beilstein J. Org. Chem. 2019, 15, 1236–1256, doi:10.3762/bjoc.15.121

• presence of I2 as catalyst. The mechanism follows the initial formation of the imine compound between the aldehyde and the arylamine, followed by an imino-Diels–Alder reaction with the enolate generated from the ketosteroid. The reaction is highly regioselective for the enolization of the ketone, thus

Mechanochemistry of supramolecules

• Anima Bose and
• Prasenjit Mal

Beilstein J. Org. Chem. 2019, 15, 881–900, doi:10.3762/bjoc.15.86

• azobenzene [58]. The cyclopalladation process was proved to be a highly regioselective process and the observed palladation rate was faster compared to the conventional solution-phase method. An equimolar amount of 4'-(N,N-dimethylamino)-4-nitroazobenzene and Pd(OAc)2 in the presence of 25 μL of glacial

An improved synthesis of adefovir and related analogues

• David J. Jones,
• Eileen M. O’Leary and
• Timothy P. O’Sullivan

Beilstein J. Org. Chem. 2019, 15, 801–810, doi:10.3762/bjoc.15.77

• phosphonate (11) was condensed with paraformaldehyde in the presence of catalytic triethylamine (Scheme 2) [41]. Iodide 9 was accessed in two steps from adenine (3). The highly regioselective alkylation of adenine (3) with an excess (4.0 equiv) of 1,2-dibromoethane furnished bromide 12 in 78% yield. Despite