Advances in radical peroxidation with hydroperoxides

• Oleg V. Bityukov,
• Pavel Yu. Serdyuchenko,
• Andrey S. Kirillov,
• Gennady I. Nikishin,
• Vera A. Vil’ and
• Alexander O. Terent’ev

Beilstein J. Org. Chem. 2024, 20, 2959–3006, doi:10.3762/bjoc.20.249

• mainly include: nucleophilic addition or nucleophilic substitution with H2O2 or ROOH [17][18], autoxidation with O2, pericyclic reactions of unsaturated bonds with O3 or O2, and metal-catalyzed peroxidation (Isayama–Mukaiyama hydrosilylperoxidation [19][20], for example) [21][22][23]. As the topic is

• broad, the present review mainly focused on radical and metal-catalyzed functionalization of C–H bonds or unsaturated bond with hydroperoxides (Scheme 2). The aim of this review is to cover recent studies in which alkylperoxy radicals have been used for the peroxidation of C(sp3) and C(sp2) sites

• product 32 formation is similar to the metal-catalyzed peroxidation described in Scheme 12 in the case of using the Cu(II)/TBHP oxidation system. Under metal-free conditions the tert-butoxy radical A is probably formed via homolytic thermal decomposition of TBHP. Recently, the electrochemical generation

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

• overview of arylation of carbon and heteroatom substrates via diaryliodonium salts in metal-free conditions. This review emphasizes the significance and potential of DIASs in contemporary organic chemistry. Review C-Arylation Over the past decade, there has been a surge of interest in metal-catalyzed C

• -arylations utilizing diaryliodonium salts, marked by significant contributions, notably from research teams led by Sanford [53] and Gaunt [54]. The synthesis of carbon–carbon bonds through metal-free approaches serves as a valuable complement to transition-metal-catalyzed couplings. This is particularly

• N-arylation could be controlled by adjusting the steric and/or electronic properties of the diaryliodonium salt and the amide. This approach was helpful in the formation of O-arylimidates previously unattainable using metal-catalyzed methods. S-Arylation The aryl sulfide moiety is widely present in

C–H Trifluoromethylthiolation of aldehyde hydrazones

• Victor Levet,
• Balu Ramesh,
• Congyang Wang and
• Tatiana Besset

Beilstein J. Org. Chem. 2024, 20, 2883–2890, doi:10.3762/bjoc.20.242

• various transformations [54][55][56][57][58][59][60][61][62][63][64]. In consequence, a large number of transition-metal-catalyzed or radical-mediated processes for C–H functionalization of aldehyde hydrazones has flourished over the years. An ideal scenario for a direct and sustainable synthetic route

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

• expand the scope of transition metal-catalyzed substitution reactions. Since its discovery in 2022, copper-catalyzed yne-allylic substitution has undergone rapid development and significant progress has been made using the key copper vinyl allenylidene intermediates. This review summarizes the

• propargylic substitution and allylic substitution, but represents a new type of reaction mode, and greatly expands the scope of transition metal-catalyzed substitution reactions. Currently, yne-allylic substitutions affording 1,3- or 1,4-enynes, remote substitutions through dearomatization-rearomatization

5th International Symposium on Synthesis and Catalysis (ISySyCat2023)

• Anthony J. Burke and
• Elisabete P. Carreiro

Beilstein J. Org. Chem. 2024, 20, 2704–2707, doi:10.3762/bjoc.20.227

• performance. In their contribution “Metal-catalyzed coupling/carbonylative cyclizations for accessing dibenzodiazepinones: an expedient route to clozapine and other drugs”, Moutayakine and Burke described a new synthetic route for the synthesis of 10,11-dihydro-5H-dibenzo[b,e][1,4]diazepinone (DBDAP

Transition-metal-free synthesis of arylboronates via thermal generation of aryl radicals from triarylbismuthines in air

• Yuki Yamamoto,
• Yuki Konakazawa,
• Kohsuke Fujiwara and
• Akiya Ogawa

Beilstein J. Org. Chem. 2024, 20, 2577–2584, doi:10.3762/bjoc.20.216

• variety of transition-metal-catalyzed reactions and photoredox reactions using arylboronates as aryl sources have been energetically investigated for the construction of carbon–carbon or carbon–heteroatom bonds [12][13][14][15]. The preparation of arylboronates often requires pre-functionalized substrates

• with halogen or triflate groups. Recently, transition-metal-catalyzed direct borylation of arenes via C–H bond activation has been reported, although the design of the substrate and ligands is somewhat complicated [16][17][18][19][20][21][22]. Since the complete removal of catalyst-derived metal

• diborons can capture the in situ-generated carbon-centered radicals [28][29][30][31][32][33][34][35][36]. Among the aryl sources in organic synthesis, triarylbismuthines are shelf-stable and easy-to-handle reagents with appropriate reactivities in transition-metal-catalyzed reactions and radical reactions

A review of recent advances in electrochemical and photoelectrochemical late-stage functionalization classified by anodic oxidation, cathodic reduction, and paired electrolysis

• Nian Li,
• Ruzal Sitdikov,
• Ajit Prabhakar Kale,
• Joost Steverlynck,
• Bo Li and
• Magnus Rueping

Beilstein J. Org. Chem. 2024, 20, 2500–2566, doi:10.3762/bjoc.20.214

• [3]. Transition-metal-catalyzed LSF strategies have been well-established over the past decades. More recently, with the vigorous development of photochemistry and electrochemistry, numerous innovative reports on LSF using photo-, electro-, and photoelectrochemistry have emerged. These areas have

• pharmaceutical drugs and natural products. We classify these advancements into three types: anodic oxidation, cathodic reduction, and paired electrolysis (Figure 1). This review considers direct electrolysis (oxidation or reduction), mediator-induced electrolysis, and metal-catalyzed and photocatalyzed

• product (Scheme 15). The synthesis of aziridines can be achieved via the formation of nitrenes in either a metal-catalyzed or metal-free fashion. In this context, Wickens and colleagues presented a remarkable dication pool strategy for accessing N-alkylaziridines via metastable dicationic intermediates

gem-Difluorination of carbon–carbon triple bonds using Brønsted acid/Bu₄NBF₄ or electrogenerated acid

• Mizuki Yamaguchi,
• Hiroki Shimao,
• Kengo Hamasaki,
• Keiji Nishiwaki,
• Shigenori Kashimura and
• Kouichi Matsumoto

Beilstein J. Org. Chem. 2024, 20, 2261–2269, doi:10.3762/bjoc.20.194

• fluorobenziodoxole, are also utilized as F+ equivalents to introduce fluorine atoms into organic molecules. In addition, various trifluoromethylation reagents have been developed so far [5][6][7][8][9][10][11][12][13][14][15][16][17][18]. Transition-metal-catalyzed fluorination and trifluoromethylation methods have

Heterocycle-guided synthesis of m-hetarylanilines via three-component benzannulation

• Andrey R. Galeev,
• Maksim V. Dmitriev,
• Alexander S. Novikov and
• Andrey N. Maslivets

Beilstein J. Org. Chem. 2024, 20, 2208–2216, doi:10.3762/bjoc.20.188

• mainly via metal-catalyzed C–N or C–C bond formation. Despite recent advances in the area of remote C–H functionalization, this strategy still requires some pre-functionalization of the starting material or the use of directing groups [28][29][30][31][32]. An alternative strategy is based on aromatic

Efficacy of radical reactions of isocyanides with heteroatom radicals in organic synthesis

• Akiya Ogawa and
• Yuki Yamamoto

Beilstein J. Org. Chem. 2024, 20, 2114–2128, doi:10.3762/bjoc.20.182

• ), but is also widely used in transition-metal-catalyzed carbonylation reactions [1][2]. However, carbon monoxide is a flammable gas with a wide explosive range, although colorless and odorless, and requires special care in handling due to its high toxicity. In addition, when carbon monoxide is used in a

Development of a flow photochemical process for a π-Lewis acidic metal-catalyzed cyclization/radical addition sequence: in situ-generated 2-benzopyrylium as photoredox catalyst and reactive intermediate

• Masahiro Terada,
• Zen Iwasaki,
• Ryohei Yazaki,
• Shigenobu Umemiya and
• Jun Kikuchi

Beilstein J. Org. Chem. 2024, 20, 1973–1980, doi:10.3762/bjoc.20.173

• Abstract A flow photochemical reaction system for a π-Lewis acidic metal-catalyzed cyclization/radical addition sequence was developed, which utilizes in situ-generated 2-benzopyrylium intermediates as the photoredox catalyst and electrophilic substrates. The key 2-benzopyrylium intermediates were

• [26][27][28][29] is increased. Thus, the flow photochemical process is crucial and beneficial to product formation. Recently, we reported a sequential transformation consisting of a π-Lewis acidic metal-catalyzed cyclization [30][31][32][33][34][35][36][37][38][39][40][41][42][43][44][45] and

• improved the yield of 3t (78%), presumably because of the retardation of the desilylation process (from B to C in Scheme 1a). Conclusion We have demonstrated a flow reaction system for a π-Lewis acidic metal-catalyzed cyclization/photochemical radical addition sequence, affording, in most cases, the 1H

The Groebke–Blackburn–Bienaymé reaction in its maturity: innovation and improvements since its 21st birthday (2019–2023)

• Cristina Martini,
• Muhammad Idham Darussalam Mardjan and
• Andrea Basso

Beilstein J. Org. Chem. 2024, 20, 1839–1879, doi:10.3762/bjoc.20.162

Electrophotochemical metal-catalyzed synthesis of alkylnitriles from simple aliphatic carboxylic acids

• Yukang Wang,
• Yan Yao and
• Niankai Fu

Beilstein J. Org. Chem. 2024, 20, 1497–1503, doi:10.3762/bjoc.20.133

• .20.133 Abstract We report a practical and sustainable electrophotochemical metal-catalyzed protocol for decarboxylative cyanation of simple aliphatic carboxylic acids. This environmentally friendly method features easy availability of substrates, broad functional group compatibility, and directly

• combination with electrochemical copper catalysis might allow rapid access to alkylnitriles in a generic fashion (Figure 1C). Herein, we disclose the successful implementation of this strategy and present a mild, practical, and broadly applicable electrophotochemical metal-catalyzed protocol for the direct

• efficiency. Results and Discussion Our study of this new electrophotochemical metal-catalyzed decarboxylative cyanation commenced with the evaluation of various combinations of Ce and Cu catalysts. A simple undivided cell using a carbon felt, inexpensive and practical porous material as the anode, and a Pt

Transition-metal-catalyst-free electroreductive alkene hydroarylation with aryl halides under visible-light irradiation

• Kosuke Yamamoto,
• Kazuhisa Arita,
• Masami Kuriyama and
• Osamu Onomura

Beilstein J. Org. Chem. 2024, 20, 1327–1333, doi:10.3762/bjoc.20.116

• versatile building blocks in organic syntheses. To achieve this transformation with high efficiency and predictable regioselectivity, numerous efforts have been made to develop transition-metal-catalyzed reactions based on a C–H activation strategy [1][2][3][4] or the reductive coupling of aryl halides with

Manganese-catalyzed C–C and C–N bond formation with alcohols via borrowing hydrogen or hydrogen auto-transfer

• Mohd Farhan Ansari,
• Atul Kumar Maurya,
• Abhishek Kumar and
• Saravanakumar Elangovan

Beilstein J. Org. Chem. 2024, 20, 1111–1166, doi:10.3762/bjoc.20.98

• to the scientific community [10][11][12]. In this process, first, the metal-catalyzed dehydrogenation of the alcohol provides a reactive substrate for coupling with nucleophiles and the active metal hydride species. Later, the borrowed hydrogen is used in the final step to reduce unsaturated

• the several alcohols and primary amines in the presence of t-BuOK (0.75 equiv) in toluene at 80 °C for 24–48 h and selectively produced the N-alkylated products with good yields (Scheme 3). More interestingly, the first non-noble-metal catalyzed the most challenging N-methylation of amines with

Carbonylative synthesis and functionalization of indoles

• Alex De Salvo,
• Raffaella Mancuso and
• Xiao-Feng Wu

Beilstein J. Org. Chem. 2024, 20, 973–1000, doi:10.3762/bjoc.20.87

• reductive elimination and the generated Pd(0) species gets oxidated by the oxygen to the active Pd(II) species (Scheme 7). Synthesis of indoles by metal-catalyzed reductive cyclization reaction of organic nitro compounds with carbon monoxide as reductant In the last 60 years, the metal-catalyzed

• indoles Metal-catalyzed cyclocarbonylative coupling reaction of indoles to 6H-isoindolo[2,1-a]indol-6-one scaffolds Substituted 6H-isoindolo[2,1-a]indol-6-ones are important structural components of many naturally occurring and pharmacologically active compounds [45][46][47][48][49][50][51]. They are also

• metal-catalyzed cyclocarbonylation in an efficient synthetic pathway towards 6H-isoindolo[2,1-a]indol-6-ones. In three of these, the products were obtained through Pd-catalyzed cyclization of 2-(2-haloaryl)indoles: Yoo et al. reported the synthesis by using various 2-(2-bromophenyl)-1H-indoles, PdCl2

Three-component N-alkenylation of azoles with alkynes and iodine(III) electrophile: synthesis of multisubstituted N-vinylazoles

• Jun Kikuchi,
• Roi Nakajima and
• Naohiko Yoshikai

Beilstein J. Org. Chem. 2024, 20, 891–897, doi:10.3762/bjoc.20.79

• motif in bioactive compounds and the synthetic utility of its olefinic C=C bond. The most extensively explored approach to this transformation is the transition metal-catalyzed C–N coupling between azoles and vinylating agents, including vinyl halides [4], boronates [5], sulfonium salts [6][7][8], and

• other metal-catalyzed conditions [12][13] or base-mediated conditions [14], with varying scopes of azoles and alkynes. Despite such advances, the hydroazolation approach is intrinsically limited to the preparation of mono- or disubstituted vinylazoles. Herein, we report on a three-component N-vinylation

Advancements in hydrochlorination of alkenes

• Daniel S. Müller

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

• on metal-catalyzed radical hydrochlorinations [11] and anti-Markovnikov hydrochlorination reactions, highlighting the ongoing challenges in achieving a simple addition of HCl across a simple double bond. During our literature review for this article, we identified two other significant reviews

• the metal-catalyzed hydrochlorination of alkenes based on MH HAT reactions (Scheme 23) [80]. They discovered that a combination of a cobalt catalyst, a silane, and tosyl chloride promoted the hydrochlorination of terminal unactivated alkenes. The scope of the reaction is relatively broad when

• activated alkenes, extending this tolerance to the polar hydrochlorination of terminal alkenes remains a challenge. Metal-catalyzed radical hydrochlorination reactions have emerged as a practical solution, providing a versatile approach to hydrochlorinate a wide range of alkenes. Methods such as ours

Regioselective quinazoline C2 modifications through the azide–tetrazole tautomeric equilibrium

• Dāgs Dāvis Līpiņš,
• Andris Jeminejs,
• Una Ušacka,
• Anatoly Mishnev,
• Māris Turks and
• Irina Novosjolova

Beilstein J. Org. Chem. 2024, 20, 675–683, doi:10.3762/bjoc.20.61

• efficiencies [5][6][7]. Consequently, ongoing efforts focus on advancing methodologies for synthesizing established quinazoline-based drugs and acquiring novel modified quinazoline derivatives for pharmaceutical or materials science purposes. Aromatic nucleophilic substitution [8] or metal-catalyzed reactions

Palladium-catalyzed three-component radical-polar crossover carboamination of 1,3-dienes or allenes with diazo esters and amines

• Geng-Xin Liu,
• Xiao-Ting Jie,
• Ge-Jun Niu,
• Li-Sheng Yang,
• Xing-Lin Li,
• Jian Luo and
• Wen-Hao Hu

Beilstein J. Org. Chem. 2024, 20, 661–671, doi:10.3762/bjoc.20.59

• . Multicomponent reactions (MCRs) by virtue of high efficiency for the construction of complex chemicals, have shown the superiority in high step and atom economy in organic synthesis [25][26][27]. Over the past two decades, our group and others have developed a transition-metal-catalyzed MCR strategy involving

HPW-Catalyzed environmentally benign approach to imidazo[1,2-a]pyridines

• Luan A. Martinho and
• Carlos Kleber Z. Andrade

Beilstein J. Org. Chem. 2024, 20, 628–637, doi:10.3762/bjoc.20.55

• (insomnia). Some recent synthetic approaches to imidazo[1,2-a]pyridine scaffolds include synthetic pathways of transition metal-catalyzed reactions [14], cyclization [15], condensation [16], heteroannular [17], and photocatalytic reactions [18]. These approaches usually involve non-trivial reaction

Mechanisms for radical reactions initiating from N-hydroxyphthalimide esters

• Carlos R. Azpilcueta-Nicolas and
• Jean-Philip Lumb

Beilstein J. Org. Chem. 2024, 20, 346–378, doi:10.3762/bjoc.20.35

• electronically excited substrate (*S) through an energy transfer (EnT) mechanism (path c). In addition to these mechanistic blueprints, the formation of charge-transfer complexes involving NHPI esters, as well as examples of photoinduced transition metal-catalyzed activation will be discussed. Depending on the

• , the aminodecarboxylation reaction proved unsuccessful when employing alternative photocatalysts such as Ru(bpy)3Cl2 or eosin Y, underscoring the distinctive ability of q-OAc to activate TCNHPI esters via EDA complex formation. Photoinduced transition metal-catalyzed mechanisms The in situ formation of

Nucleophilic functionalization of thianthrenium salts under basic conditions

• Xinting Fan,
• Duo Zhang,
• Xiangchuan Xiu,
• Bin Xu,
• Yu Yuan,
• Feng Chen and
• Pan Gao

Beilstein J. Org. Chem. 2024, 20, 257–263, doi:10.3762/bjoc.20.26

• regioselectivity. Significant advancements in the synthesis of arylthianthrenium salts have prompted a growing interest in their utilization as versatile precursors for the conversion of C–H bonds in arenes into C–C/X bonds through transition-metal-catalyzed cross-coupling processes [12][13][14][15][16][17][18][19

• -metal-catalyzed cross-coupling [32][33] and aminofunctionalization [34] of alkenes were achieved, benefiting from the unique reactivity of organothianthrenium species that are generated through the reaction of alkenes and thianthrene sulfoxide (TT=O) or thianthrene (TT) (Scheme 1b). Alcohols are widely

• generation of alkyl radicals [39]. After that, a series of methods for the modification of alkylthianthrenium salts have been developed, including the transition-metal-catalyzed cross-coupling with terminal alkynes [40], sulfonylation with DABCO·(SO2)2 [41][42][43], or alkylation of active alkenes [44][45

Catalytic multi-step domino and one-pot reactions

• Svetlana B. Tsogoeva

Beilstein J. Org. Chem. 2024, 20, 254–256, doi:10.3762/bjoc.20.25

• advances in the field. A Review article by Pounder, Tam, and co-authors summarizes new transition-metal-catalyzed domino reactions of strained bicyclic alkenes, including both homo- and heterobicyclic alkenes highly useful for the construction of biologically significant compounds with multiple

Chiral phosphoric acid-catalyzed transfer hydrogenation of 3,3-difluoro-3H-indoles

• Yumei Wang,
• Guangzhu Wang,
• Yanping Zhu and
• Kaiwu Dong

Beilstein J. Org. Chem. 2024, 20, 205–211, doi:10.3762/bjoc.20.20

• great attention in organic synthesis. Various methods [9], including reductive hydrogenation [10][11], kinetic resolution [12][13][14], functionalization of indole [15], and de novo construction of chiral 2-substituted indolines, have been developed [16][17][18][19][20]. In recent years, the metal

• -catalyzed asymmetric hydrogenation of indoles to synthesize chiral indolines has been widely studied (Scheme 1a) [21][22]. Representative examples include Ir- or Ru-catalyzed asymmetric hydrogenation of 2,3,3-trisubstituted 3H-indole [23][24]. Generally, these methods employ precious metals and/or