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

Multicomponent reactions (MCRs): a useful access to the synthesis of benzo-fused γ-lactams

• Edorta Martínez de Marigorta,
• Jesús M. de Los Santos,
• Ana M. Ochoa de Retana,
• Javier Vicario and
• Francisco Palacios

Beilstein J. Org. Chem. 2019, 15, 1065–1085, doi:10.3762/bjoc.15.104

• metal catalyst. Through a tandem three-component cross-dehydrogenative coupling (CDC), they prepared, in a single step, more than thirty isoindolinone derivatives 4, including those originated from sulfonamides and carboxamides (Scheme 1). The scope of the reaction includes aromatic, some aliphatic and

• with the nucleophilic aromatic ring in a Friedel–Crafts alkylation process, thus incorporating the carbon atom in a formal C(sp2)–H/C(sp3)–H cross-dehydrogenative coupling. Finally, an oxidation of sulfide 7 to sulfoxide 8 and the subsequent attack of amide 2 with cleavage of the C–S bond and formation

Mechanochemistry of supramolecules

• Anima Bose and
• Prasenjit Mal

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

• maximum contact (solvent-free ball milling) of the reactants [113]. An acid salt, (sodium bisulfate) was used to control the reactivity of the highly basic primary amines to transform the exceedingly exothermic reactive substrates in a high-yielding cross-dehydrogenative coupling (CDC) reaction to obtain

Molecular iodine-catalyzed one-pot multicomponent synthesis of 5-amino-4-(arylselanyl)-1H-pyrazoles

• Camila S. Pires,
• Daniela H. de Oliveira,
• Maria R. B. Pontel,
• Jean C. Kazmierczak,
• Roberta Cargnelutti,
• Diego Alves,
• Raquel G. Jacob and
• Ricardo F. Schumacher

Beilstein J. Org. Chem. 2018, 14, 2789–2798, doi:10.3762/bjoc.14.256

• -(phenylselanyl)-1H-pyrazol-5-amine was submitted to an oxidative dehydrogenative coupling to produce a diazo compound confirmed by X-ray analysis. Keywords: diaryl diselenide; diazo compound; 1H-pyrazole; molecular iodine; multicomponent reaction; Introduction Selenium-containing compounds are of great

Direct electrochemical generation of organic carbonates by dehydrogenative coupling

• Tile Gieshoff,
• Vinh Trieu,
• Jan Heijl and
• Siegfried R. Waldvogel

Beilstein J. Org. Chem. 2018, 14, 1578–1582, doi:10.3762/bjoc.14.135

• ; dehydrogenative coupling; electrochemistry; organic carbonates; Introduction Polycarbonates are high-performance polymeric materials with versatile applications in various fields with economic impact, e.g., construction, food, and pharmaceutical industry [1]. For their technical large-scale production, organic

• [28][29][30]. In combination with easily accessible carbonate sources, we tried to establish a new dehydrogenative approach to organic carbonates. Here, the study on the first direct electrochemical generation of organic carbonates by dehydrogenative coupling is presented. Results and Discussion

• potentials and the oligomerization tendency of electron-rich arenes limit the scope (see Supporting Information File 1). Conclusion The first direct electrochemical generation of organic carbonates by dehydrogenative coupling at arenes was established. Even though this ambitious method is currently

Polysubstituted ferrocenes as tunable redox mediators

• Sven D. Waniek,
• Jan Klett,
• Christoph Förster and
• Katja Heinze

Beilstein J. Org. Chem. 2018, 14, 1004–1015, doi:10.3762/bjoc.14.86

• dehydrogenative coupling reactions [34][35] and for olefin hydroamidations [36] (Scheme 1d–f). For potential applications of ferrocene derivatives as redox mediators or SET reagents, it is crucial to adjust the electrochemical potential to the potential of the substrate. The electrochemical potential of the

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

• . In addition, it is demonstrated that the mediated process is superior to the direct electrochemical functionalization. Keywords: C–C formation; electrochemical oxidative functionalization; n-Bu4NI; redox catalyst; Introduction The oxidative cross dehydrogenative coupling (CDC) of two C–H bonds has

• experiments described above, as well as related references [4], a plausible mechanism for the electrocatalytic cross dehydrogenative coupling of N-arylglycine esters 1 with C–H nucleophiles 2 is outlined in Scheme 6. The anodic oxidation of iodide generates the active species I2 or I+. Followed by a

• 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

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

• example of a double Sonogashira reaction is shown [60]. Oxidative cross-dehydrogenative coupling Copper-catalyzed mechanochemical oxidative cross-dehydrogenative coupling (CDC) reactions [61][62][63][64][65][66] of tetrahydroisoquinolines with alkynes and indoles was reported by Su and co-workers (Scheme

• bond synthesis under ball-milling conditions. Cross dehydrogenative coupling reactions between benzaldehydes and benzylamines were performed in presence of phenyliodine diacetate (PIDA) using the acid salt NaHSO4 [81]. The highly exergonic reaction (contact explosive) of acidic iodine(III) and basic

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

• reacted with o-aminobenzylamine and substituted o-aminobenzylamines to provide the desired products in decent yields (Scheme 8b). Kumar et al. demonstrated transition metal-free α-C(sp3)–H bond functionalization of amines via an oxidative cross-dehydrogenative coupling reaction [44]. They reported a one

• to generate the desired substituted dihydroquinazolines 35 in moderate to excellent yields (Scheme 9) [44]. In another example commercially available sodium hypochlorite (NaOCl) was used as an oxidant, under mild conditions in a highly efficient oxidative dehydrogenative coupling of o

• quinazolinones with I2 and DDQ [37][38][39][40]. DDQ-mediated oxidative dehydrogenation of thiazolidines and oxazolidines. Oxone-mediated oxidative dehydrogenation of intermediates from o-phenylenediamine and o-aminobenzylamine [42][43]. Transition metal-free oxidative cross-dehydrogenative coupling. NaOCl

Synthesis of 2-oxindoles via 'transition-metal-free' intramolecular dehydrogenative coupling (IDC) of sp² C–H and sp³ C–H bonds

• Nivesh Kumar,
• Santanu Ghosh,
• Subhajit Bhunia and
• Alakesh Bisai

Beilstein J. Org. Chem. 2016, 12, 1153–1169, doi:10.3762/bjoc.12.111

• -carbon quaternary center at the pseudo benzylic position has been achieved via a ‘transition-metal-free’ intramolecular dehydrogenative coupling (IDC). The construction of 2-oxindole moieties was carried out through formation of carbon–carbon bonds using KOt-Bu-catalyzed one pot C-alkylation of β-N

• -arylamido esters with alkyl halides followed by a dehydrogenative coupling. Experimental evidences indicated toward a radical-mediated path for this reaction. Keywords: C−H functionalization; intramolecular dehydrogenative coupling (IDC); iodine; N-iodosuccinimide; oxidants; 2-oxindoles; Introduction The

• oxidative coupling of two C–H bonds [also termed as cross-dehydrogenative-coupling (CDC)] in the formation of C–C bonds [11][12][13][14][15][16]. This was facilitated by the introduction of transition metals in organic synthesis providing an amazing tool to explore these oxidative coupling reactions in an

Cascade alkylarylation of substituted N-allylbenzamides for the construction of dihydroisoquinolin-1(2H)-ones and isoquinoline-1,3(2H,4H)-diones

• Ping Qian,
• Bingnan Du,
• Wei Jiao,
• Haibo Mei,
• Jianlin Han and
• Yi Pan

Beilstein J. Org. Chem. 2016, 12, 301–308, doi:10.3762/bjoc.12.32

• cross-dehydrogenative coupling (CDC) reactions of alkanes, which were reported by Li and other groups [11][12][13][14][15]. Recently, several types of reactions with alkanes as substrates have been developed, such as the Minisci reaction with heteroarenes [16][17], radical addition to unsaturated bonds

Enantioselective additions of copper acetylides to cyclic iminium and oxocarbenium ions

• Jixin Liu,
• Srimoyee Dasgupta and
• Mary P. Watson

Beilstein J. Org. Chem. 2015, 11, 2696–2706, doi:10.3762/bjoc.11.290

• for enantioselective alkynylations of cyclic electrophiles. The first enantioselective, copper-catalyzed alkynylation of a cyclic iminium ion was reported by Li’s research group in 2004 [22]. Building on their development of a cross-dehydrogenative coupling (CDC) reaction between benzylic amines and

Pd(OAc)₂-catalyzed dehydrogenative C–H activation: An expedient synthesis of uracil-annulated β-carbolinones

• Biplab Mondal,
• Somjit Hazra,
• Tarun K. Panda and
• Brindaban Roy

Beilstein J. Org. Chem. 2015, 11, 1360–1366, doi:10.3762/bjoc.11.146

• rich indole C3–H bond for the synthesis of uracil annulated β-carbolinones [54][55][56]. Herein, we report our novel approach towards the synthesis of uracil annulated β-carbolinones via an intramolecular dehydrogenative coupling reaction of indole-2-carboxamides. Results and Discussion We started our

• point for catalyst screening. The amide 4a (R1 = R2 = R3 = R4 = Me) was used as a model substrate for this dehydrogenative coupling reaction. The reaction was set up in the presence of Pd(OAc)2 (10 mol %), Cu(OAc)2 (2 equiv) in DMF under open air at 70 °C (Table 1, entry 1). After 8 h we obtained 35

• the eluent to afford product 5. For details see Supporting Information File 1. Naturally occurring β-carbolinones. ORTEP diagram of 5h. Preparation of starting substrate. Synthesis of various β-carbolinone derivatives. Proposed mechanistic pathway. Optimization of intramolecular dehydrogenative

Cross-dehydrogenative coupling for the intermolecular C–O bond formation

• Igor B. Krylov,
• Vera A. Vil’ and
• Alexander O. Terent’ev

Beilstein J. Org. Chem. 2015, 11, 92–146, doi:10.3762/bjoc.11.13

• -dehydrogenative C–O coupling reaction are dictated mainly by the nature of the C-reagent. Hence, in the present review the data are classified according to the structures of C-reagents, and, in the second place, according to the type of oxidative systems. Besides the typical cross-dehydrogenative coupling

• ; C–H functionalization; C–O bond formation; cross-dehydrogenative coupling; oxidative cross-coupling; Introduction The development of methods for the cross-dehydrogenative coupling (CDC; or oxidative cross coupling) is an important field of modern organic chemistry. These terms commonly refer to

• -dehydrogenative coupling can be employed to form a new bond with high atomic efficiency and does not require additional synthetic steps for the introduction of functional groups (for example, such as -Hal, -OTf, -BR2, -SnR3, -SiR3, -ZnHal, -MgHal) into molecules necessary in other cross-coupling reactions

Sequential decarboxylative azide–alkyne cycloaddition and dehydrogenative coupling reactions: one-pot synthesis of polycyclic fused triazoles

• Kuppusamy Bharathimohan,
• Thanasekaran Ponpandian,
• A. Jafar Ahamed and
• Nattamai Bhuvanesh

Beilstein J. Org. Chem. 2014, 10, 3031–3037, doi:10.3762/bjoc.10.321

• methodology is more convenient to produce the complex polycyclic molecules in a simple way. Keywords: copper(II) acetate; decarboxylative CuAAC; dehydrogenative coupling; fused triazoles; one-pot synthesis; Introduction The copper-catalyzed Huisgen [3 + 2] cycloaddition (or copper-catalyzed azide–alkyne

• were developed for the synthesis of fused triazoles [40]. Ackermann referred to an intramolecular dehydrogenative coupling of 1,4-disubstituted triazoles to achieve tri- and tetracyclic triazoles [34]. Recently, Lautens et al. [41] described a one-pot synthesis of fused triazoles through CuAAC reaction

• According to the report of Kolarovič et al., the decarboxylative CuAAC reaction occurs efficiently with a CuSO4/NaAsc/DMSO catalytic system [6]. The palladium-catalyzed oxidative dehydrogenative coupling reaction may be effected by various oxidants [42][43] such as Ag2O, AgOAc, Ag2CO3, Na2S2O8, Cu(OPiv)2

Exploration of C–H and N–H-bond functionalization towards 1-(1,2-diarylindol-3-yl)tetrahydroisoquinolines

• Michael Ghobrial,
• Marko D. Mihovilovic and
• Michael Schnürch

Beilstein J. Org. Chem. 2014, 10, 2186–2199, doi:10.3762/bjoc.10.226

• salt [11]. This synthesis has been streamlined by cross dehydrogenative coupling (CDC) – a powerful method for C–C-bond formation via the C–H bonds of a pro-nucleophile and a pro-electrophile [12][13][14]. A landmark contribution published by Li and co-workers reported the successful introduction of

• wanted to use direct functionalization either via C–H activation or cross dehydrogenative coupling for C–C-bond-forming reactions avoiding the use of two prefunctionalized building blocks. Naturally, C–N-bond formation should proceed via Buchwald–Hartwig coupling. The target molecules can be considered

Iron-catalyzed decarboxylative alkenylation of cycloalkanes with arylvinyl carboxylic acids via a radical process

• Jincan Zhao,
• Hong Fang,
• Jianlin Han and
• Yi Pan

Beilstein J. Org. Chem. 2013, 9, 1718–1723, doi:10.3762/bjoc.9.197

• reactions. Additionally, metal-free methodologies, which use TBHP, PhI(OAc)2, TBAI, I2 or Lewis/Brønsted acids, have also been employed for cross-dehydrogenative coupling reactions [48][49][50][51][52][53][54][55][56][57]. Owing to the general low reactivity of cycloalkane C(sp3)–H bonds, the direct

A³-Coupling catalyzed by robust Au nanoparticles covalently bonded to HS-functionalized cellulose nanocrystalline films

• Jian-Lin Huang,
• Derek G. Gray and
• Chao-Jun Li

Beilstein J. Org. Chem. 2013, 9, 1388–1396, doi:10.3762/bjoc.9.155

• environmental pollution [1][2]. In the past few decades, aqueous-phase organic reactions have achieved great success [3][4][5]. The classic examples include the Grignard-type reactions [6][7], transition-metal catalyzed C–C bond formations [8][9] and cross-dehydrogenative coupling (CDC) reactions [10][11][12

Ru-catalyzed dehydrogenative coupling of carboxylic acids and silanes - a new method for the preparation of silyl ester

• Guo-Bin Liu and
• Hong-Yun Zhao

Beilstein J. Org. Chem. 2008, 4, No. 27, doi:10.3762/bjoc.4.27

• the transition metal-catalyzed cross-coupling of an active hydrogen-moiety containing substances such as water and alcohols with silanes [27]. There are still few examples of dehydrogenative coupling reaction of carboxylic acids with silanes. Silylating agents such as allyltrimethylsilane

• finding that a catalytic system of dodecacarbonyltriruthenium and ethyl iodide [Ru3(CO)12/EtI] effectively promotes the dehydrogenative coupling of carboxylic acids with silanes, yielding the corresponding silyl esters selectively. The results are summarized in Scheme 1 and Table 1–Table 4

• . Dehydrogenative coupling reactions were carried out by heating a mixture of carboxylic acid, silane and a catalytic amount of Ru3(CO)12/EtI in solvents under a nitrogen atmosphere for several hours (Scheme 1, Table 1–Table 4, dehydrocoupling reaction was monitored by GC). The transformation of propionic acid with

Conformational rigidity of silicon- stereogenic silanes in asymmetric catalysis: A comparative study

• Sebastian Rendler and
• Martin Oestreich

Beilstein J. Org. Chem. 2007, 3, No. 9, doi:10.1186/1860-5397-3-9

• reagents for the silicon-to-carbon chirality transfer. Kinetic resolution of secondary alcohols using a dehydrogenative coupling reaction. Catalytic cycle for hydrosilylation. Postulated catalytic cycle for dehydrogenative coupling. Supporting Information Supporting Information File 88: Supporting