Ready access to 7,8-dihydroindolo[2,3-d][1]benzazepine-6(5H)-one scaffold and analogues via early-stage Fischer ring-closure reaction

• Irina Kuznetcova,
• Felix Bacher,
• Daniel Vegh,
• Hsiang-Yu Chuang and
• Vladimir B. Arion

Beilstein J. Org. Chem. 2022, 18, 143–151, doi:10.3762/bjoc.18.15

• lithium hydroxide monohydrate [29] to give the desired indole-2-acetic acid (14) in 95% yield. The peptide coupling reaction [30] of indole-2-acetic acid (14) and 2-iodoaniline afforded 15 in 23% yield (Scheme 3). Subsequent protection of both the indole and the amide nitrogen with tert-butyloxycarbonyl

Recent advances and perspectives in ruthenium-catalyzed cyanation reactions

• Thaipparambil Aneeja,
• Cheriya Mukkolakkal Abdulla Afsina,
• Padinjare Veetil Saranya and
• Gopinathan Anilkumar

Beilstein J. Org. Chem. 2022, 18, 37–52, doi:10.3762/bjoc.18.4

• oxidative cyanation of aza-Baylis–Hillman adducts. Synthesis of 1° alkyl nitriles using [Ru(bpy)3](PF6)2 as the photocatalyst. Synthesis of 2° and 3° alkyl nitriles using [Ru(bpy)3](PF6)2 as the photocatalyst. Photoredox cross coupling reaction. Synthesis of α-amino nitriles from amines via a one-pot

DABCO-promoted photocatalytic C–H functionalization of aldehydes

• Bruno Maia da Silva Santos,
• Mariana dos Santos Dupim,
• Cauê Paula de Souza,
• Thiago Messias Cardozo and
• Fernanda Gadini Finelli

Beilstein J. Org. Chem. 2021, 17, 2959–2967, doi:10.3762/bjoc.17.205

• through this step were used in a well-stablished nickel-catalyzed cross-coupling reaction [19][27][28][29][30] with aryl bromides as a proof of concept, leading to the synthesis of aryl ketones. We also present computational calculations of the HAT reaction step with the DABCO radical cation as the

Iron-catalyzed domino coupling reactions of π-systems

• Austin Pounder and
• William Tam

Beilstein J. Org. Chem. 2021, 17, 2848–2893, doi:10.3762/bjoc.17.196

• first Fe-catalyzed cross-coupling reaction between Grignard reagents and vinyl halides [37]. As of late, the development of Fe-catalyzed cross-coupling methodology and mechanistic rationales have burgeoned [38]. Today, the rate of growth within the field of iron catalysis is much greater than that

• functionalized compound (Scheme 1b). Lastly, the reaction between two C–H compounds to form a C–C bond, formally eliminating H2, hence the dehydrogenative reference (Scheme 1c). As this coupling reaction does not require functionalization prior to coupling, it shortens the synthetic route, and lowers the

• iron-catalyzed cross-coupling reactions of alkyl halides began in 2004 when Nakamura first reported the TMEDA-mediated Fe-catalyzed cross-coupling reaction between secondary bromides with aryl Grignard reagents [52]. Since then, several reports of alkyl halide cross-coupling reactions have been

Selective sulfonylation and isonitrilation of para-quinone methides employing TosMIC as a source of sulfonyl group or isonitrile group

• Chuanhua Qu,
• Run Huang,
• Yong Li,
• Tong Liu,
• Yuan Chen and
• Guiting Song

Beilstein J. Org. Chem. 2021, 17, 2822–2831, doi:10.3762/bjoc.17.193

• sulfones is a valuable and appealing task in synthetic chemistry. Traditionally, diarylmethyl sulfones are synthesized by transition-metal-catalyzed deoxy C–S bond-coupling reaction of sodium arylsulfinates with diarylmethanols [11], C–H functionalization of alkyl sulfones with aryl halides [12], and via a

Synthetic strategies toward 1,3-oxathiolane nucleoside analogues

• Umesh P. Aher,
• Dhananjai Srivastava,
• Girij P. Singh and
• Jayashree B. S

Beilstein J. Org. Chem. 2021, 17, 2680–2715, doi:10.3762/bjoc.17.182

• by Humber et al. [45]. They started with a coupling reaction of (+)-thiolactic acid 3p and 2-benzoyloxyacetaldehyde (3a) using boron trifluoride etherate. A diastereomeric mixture of oxathiolane acids 29 and 30 was prepared in a 1:2 ratio in good yield (Scheme 7). Further separation of the

• ammonolysis in methanol affords compound 1c. The silylation of 1c with TBDPSCl was carried out, and then coupling reaction with tert-Boc-Met-Leu-Phe-OH in the presence of DCC and HOBt provided compound 98. The tert-Boc protecting group was further removed in formic acid, and the resulting nucleoside peptide

Ligand-dependent stereoselective Suzuki–Miyaura cross-coupling reactions of β-enamido triflates

• Tomáš Chvojka,
• Athanasios Markos,
• Svatava Voltrová,
• Radek Pohl and
• Petr Beier

Beilstein J. Org. Chem. 2021, 17, 2657–2662, doi:10.3762/bjoc.17.179

• stereoselective outcome of the Suzuki cross-coupling reaction of various (Z)-β-enamido triflates (Scheme 1B). Results and Discussion We initiated our study by examining the Suzuki cross-coupling of vinyl triflate 1a and 3-nitrophenylboronic acid. First, the influence of the catalyst on the stereoselective outcome

Electrocatalytic C(sp³)–H/C(sp)–H cross-coupling in continuous flow through TEMPO/copper relay catalysis

• Bin Guo and
• Hai-Chao Xu

Beilstein J. Org. Chem. 2021, 17, 2650–2656, doi:10.3762/bjoc.17.178

• electrocatalytic dehydrogenative cross-coupling reaction of tetrahydroisoquinolines with terminal alkynes in continuous flow (Scheme 1D). These reactions require low loadings of supporting electrolyte and proceed through Cu/TEMPO relay catalysis without need for additional ligands. Results and Discussion The

• electrochemistry is an ideal tool for promoting dehydrogenative cross-coupling reactions as no external chemical oxidants are needed [11][12][13][14][15][16][17][18][19]. In this context, Mei and co-workers have reported an elegant TEMPO/[L*Cu] co-catalyzed asymmetric electrochemical dehydrogenative cross-coupling

• reaction of tetrahydroisoquinolines with terminal alkynes (Scheme 1C) [10]. The chiral ligand was found to be critical for the stereoinduction as well as product formation for these electrochemical reactions that are conducted in batch. Continuous-flow electrochemical microreactors offer several advantages

Visible-light-mediated copper photocatalysis for organic syntheses

• Yajing Zhang,
• Qian Wang,
• Zongsheng Yan,
• Donglai Ma and
• Yuguang Zheng

Beilstein J. Org. Chem. 2021, 17, 2520–2542, doi:10.3762/bjoc.17.169

• copper-catalyzed C–O cross-coupling reaction. Results of mechanistic studies indicated that in this case a CuI–phenoxide complex is a competent intermediate in the photoinduced C–O bond formation. In 2020, Nguyen and co-worker [90] reported copper-catalyzed C–O cross-coupling of glycosyl bromides with

• -base photocatalysis. Olefinic C–H functionalization and allylic alkylation. Cross-coupling of unactivated alkenes and CF3SO2Cl. Chlorosulfonylation/cyanofluoroalkylation of alkenes. Hydroamination of alkenes. Cross-coupling reaction of alkenes, alkyl halides with nucleophiles. Cross-coupling of alkenes

• . Aerobic oxidative C(sp)–S coupling reaction. Copper-catalyzed alkylation of carbazoles with alkyl halides. C–N coupling of organic halides with amides and aliphatic amines. Copper-catalyzed C–X (N, S, O) bond formation reactions. Arylation of C(sp2)–H bonds of azoles. C–C cross-coupling of aryl halides

Copper-catalyzed monoselective C–H amination of ferrocenes with alkylamines

• Zhen-Sheng Jia,
• Qiang Yue,
• Ya Li,
• Xue-Tao Xu,
• Kun Zhang and
• Bing-Feng Shi

Beilstein J. Org. Chem. 2021, 17, 2488–2495, doi:10.3762/bjoc.17.165

• -determining step. Conclusion To summarize, we have reported a copper-catalyzed direct ortho-C–H/N–H coupling reaction of ferrocenes with alkyl amines directed by 8-aminoquinoline. Fruitful mono-aminated ferrocenes were obtained in moderate to good yields and the mild conditions offered the possibility to the

Recent advances in the tandem annulation of 1,3-enynes to functionalized pyridine and pyrrole derivatives

• Yi Liu,
• Puying Luo,
• Yang Fu,
• Tianxin Hao,
• Xuan Liu,
• Qiuping Ding and
• Yiyuan Peng

Beilstein J. Org. Chem. 2021, 17, 2462–2476, doi:10.3762/bjoc.17.163

• ]. Then, they also reported another CuH-catalyzed coupling reaction of 1,3-enynes 54 and nitrile to prepare polysubstituted pyrroles 55 (Scheme 21) [66]. The substrates 54 could be easily prepared by Sonogashira coupling of terminal alkynes and vinyl halides. It is worth mentioning that the addition of

• to pyrroles. Au/Ag-catalyzed oxidative aza-annulation of 1,3-enynyl azides. The plausible mechanism of Au/Ag-catalyzed oxidative aza-annulation. Synthesis of 2-tetrazolyl-substituted 3-acylpyrroles from enynals. CuH-catalyzed coupling reaction of 1,3-enynes and nitriles to pyrroles. The mechanism of

Synthesis and investigation on optical and electrochemical properties of 2,4-diaryl-9-chloro-5,6,7,8-tetrahydroacridines

• Najeh Tka,
• Mohamed Adnene Hadj Ayed,
• Mourad Ben Braiek,
• Mahjoub Jabli and
• Peter Langer

Beilstein J. Org. Chem. 2021, 17, 2450–2461, doi:10.3762/bjoc.17.162

• 3,5-dibromoanthranilic acid (1) [61] with cyclohexanone in POCl3 through an adapted reported procedure [62] (Scheme 1). With precursor 2 in hand, we intended to expand the π-conjugation of the tetrahydroacridine core by adding diversely substituted aryl groups using the Suzuki–Miyaura cross-coupling

• reaction [63][64]. As a model reaction, we studied the coupling between 2,4-dibromo-9-chloro-5,6,7,8-tetrahydroacridine (2) and phenylboronic acid (3a). After a thorough optimization using Pd(PPh3)4 as catalyst, toluene as solvent, and K3PO4 as base, the desired bis-arylated product 4a was isolated in up

Synthesis of phenanthridines via a novel photochemically-mediated cyclization and application to the synthesis of triphaeridine

• Songeziwe Ntsimango,
• Kennedy J. Ngwira,
• Moira L. Bode and
• Charles B. de Koning

Beilstein J. Org. Chem. 2021, 17, 2340–2347, doi:10.3762/bjoc.17.152

• –Miyaura cross-coupling reaction of a variety of halogenated methoxybenzene-containing compounds with 2-(formylphenyl)boronic acids in generally good yields [15]. As a next step, the biaryl aldehydes 13a–f were converted into their corresponding oximes 14a–f in good yields as a mixture of (E) and (Z

• was demonstrated to be useful for the synthesis of the natural product trisphaeridine (3) [17]. Exposure of 1-bromo-2,4,5-trimethoxybenzene (19) to Suzuki–Miyaura coupling reaction conditions with boronic acid 20 resulted in the formation of aldehyde 21 (Scheme 5). Treatment of 21 with hydroxylamine

Transition-metal-free intramolecular Friedel–Crafts reaction by alkene activation: A method for the synthesis of some novel xanthene derivatives

• Tülay Yıldız,
• İrem Baştaş and
• Hatice Başpınar Küçük

Beilstein J. Org. Chem. 2021, 17, 2203–2208, doi:10.3762/bjoc.17.142

• synthesized the novel unactivated alkenes 4a–l containing three aryl groups as the starting materials. The synthesis of 4a is demonstrated in Scheme 1. First, 2-phenoxybenzaldehyde (1a) was synthesized by coupling reaction of phenol with commercial 2-fluorobenzaldehyde. This reaction was carried out with very

Chemical syntheses and salient features of azulene-containing homo- and copolymers

• Vijayendra S. Shetti

Beilstein J. Org. Chem. 2021, 17, 2164–2185, doi:10.3762/bjoc.17.139

• -(n-dodecyl)azulene (16) is shown in Scheme 5A. The Sonogashira cross-coupling reaction between 4,7-dibromo-6-(n-dodecyl)azulene (13) and 4,7-diethynyl-6-(n-dodecyl)azulene (16) yielded 4,7-polyazulene 17 linked through ethynyl bridges (Scheme 5B). Similarly, the Yamamoto cross-coupling reaction

• synthesized from tropolone (21) in five steps (Scheme 21A). The Suzuki–Miyaura coupling reaction of 2,6-dibromoazulene (125) with 2,2’-(9,9-dioctyl-9H-flourene-2,7-diyl)di(1,3,2-dioxaborolane) (103) furnished the polymer 126 in 31% yield (Scheme 21B). The other polymer 129 was obtained from 2,6-dibromoazulene

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

• ). Representative examples included indenoanthracenes 61a–c, bearing aryl groups linked to the alkyne, and indenoanthracenes 61d–f, containing tetramethylsilane groups at the terminal alkyne [46]. From commercially available 1,8-dichloroanthraquinone (62) and by using modified Suzuki–Miyaura coupling reaction

• conditions, Agarwal et al. synthesized a series of 1,8-diarylanthracene derivatives 64 in two steps (Scheme 14) [47]. First, the simple reduction of anthraquinone 62 employing the well-known reductive Zn/NH3 system and HCl provided 1,8-dichloroanthracene (63). A Suzuki–Miyaura coupling reaction in the

• ]anthracenes 139 bearing H, CN, or OMe groups at positions 11 and 12, to study their liquid crystalline properties (Scheme 32) [66]. Their methodology started with a Suzuki coupling reaction of substituted dibromonaphthalenes 136 and boronate diesters 137, to provide the corresponding 2,3-diphenylnaphthalenes

On the application of 3d metals for C–H activation toward bioactive compounds: The key step for the synthesis of silver bullets

• Renato L. Carvalho,
• Amanda S. de Miranda,
• Mateus P. Nunes,
• Roberto S. Gomes,
• Guilherme A. M. Jardim and
• Eufrânio N. da Silva Júnior

Beilstein J. Org. Chem. 2021, 17, 1849–1938, doi:10.3762/bjoc.17.126

Cationic oligonucleotide derivatives and conjugates: A favorable approach for enhanced DNA and RNA targeting oligonucleotides

• Mathias B. Danielsen and
• Jesper Wengel

Beilstein J. Org. Chem. 2021, 17, 1828–1848, doi:10.3762/bjoc.17.125

• containing a stretch of four DNA nucleotides in the middle, flanked by the modifications in a ´mixmer´ design, which is important for designing gapmer ASOs [31]. Another well-established method for C-5 pyrimidine modification involves the Sonogashira cross-coupling reaction between an alkyne group and a 5

2,4-Bis(arylethynyl)-9-chloro-5,6,7,8-tetrahydroacridines: synthesis and photophysical properties

• Najeh Tka,
• Mohamed Adnene Hadj Ayed,
• Mourad Ben Braiek,
• Mahjoub Jabli,
• Noureddine Chaaben,
• Kamel Alimi,
• Stefan Jopp and
• Peter Langer

Beilstein J. Org. Chem. 2021, 17, 1629–1640, doi:10.3762/bjoc.17.115

• of the temperature. We found that increasing the temperature to 90 or 100 °C did not lead to any improvement (Table 1, entries 6 and 7). The best result for the Sonogashira coupling reaction between intermediate 2 and phenylacetylene (3a) was obtained using 0.6 mol % of Pd(PPh3)4, 1.2 mol % of CuI in

• DIPEA at 80 °C for three hours. With the optimized conditions in hand, we examined the scope of the coupling reaction of 2 with different phenylacetylenes 3b–g. As shown in Table 2, tetrahydroacridine derivatives 4a–g were obtained in moderate to good yields. The yields were better for acetylenes

A recent overview on the synthesis of 1,4,5-trisubstituted 1,2,3-triazoles

• Pezhman Shiri,
• Ali Mohammad Amani and
• Thomas Mayer-Gall

Beilstein J. Org. Chem. 2021, 17, 1600–1628, doi:10.3762/bjoc.17.114

• , altogether leading to a moderate to high yield of the products (Scheme 19) [50]. A reasonable mechanism for this cyclization/coupling reaction involves the generation of a 5-copper(I)-substituted triazolide intermediate 62, which coordinates with propargyl carbonate 59. Further insertion of the C–C triple

Methodologies for the synthesis of quaternary carbon centers via hydroalkylation of unactivated olefins: twenty years of advances

• Thiago S. Silva and
• Fernando Coelho

Beilstein J. Org. Chem. 2021, 17, 1565–1590, doi:10.3762/bjoc.17.112

• C, which undergoes an oxidation process to generate carbocation D. A proton abstraction from D then affords the observed product. Cross-coupling reaction between unactivated olefins and alkyl halides under nickel catalysis The use of alkyl halides in transition-metal-catalyzed cross-couplings to

Recent advances in the application of isoindigo derivatives in materials chemistry

• Andrei V. Bogdanov and
• Vladimir F. Mironov

Beilstein J. Org. Chem. 2021, 17, 1533–1564, doi:10.3762/bjoc.17.111

• components of the OSC. The synthesis of such compounds is also based on the Suzuki coupling reaction between alkylated 6,6’-dibromoisoindigos and corresponding arylboronic derivatives, leading to the formation of target molecules in moderate yield (Scheme 11). In these compounds, the triarylamine substituent

• -coupling reaction (Scheme 19). However, the OSC of such a cell showed an efficiency of only 1%. Using polymeric isoindigo 35b as an acceptor component, a nonfullerene OSC was also obtained, which showed a record efficiency of 12.03% among the composites based on isoindigo described to date [55]. Polymeric

Iodine-catalyzed electrophilic substitution of indoles: Synthesis of (un)symmetrical diindolylmethanes with a quaternary carbon center

• Thanigaimalai Pillaiyar,
• Masoud Sedaghati,
• Andhika B. Mahardhika,
• Lukas L. Wendt and
• Christa E. Müller

Beilstein J. Org. Chem. 2021, 17, 1464–1475, doi:10.3762/bjoc.17.102

• via an iodine-catalyzed coupling reaction of trifluoromethyl(indolyl)phenylmethanol with indole derivatives. This method has also been extended to the synthesis of pentafluoro-ethylated and heptafluoro-propylated DIMs in excellent yields. Selected compounds were evaluated in radioligand binding

Double-headed nucleosides: Synthesis and applications

• Vineet Verma,
• Jyotirmoy Maity,
• Vipin K. Maikhuri,
• Ritika Sharma,
• Himal K. Ganguly and
• Ashok K. Prasad

Beilstein J. Org. Chem. 2021, 17, 1392–1439, doi:10.3762/bjoc.17.98

• :5,6-di-O-isopropylidene-ᴅ-glucose [50]. Furanoside 42 was reacted with the silyl-protected nucleobases 43a–c and 47a,b in the presence of trimethylsilyl trifluoromethanesulfonate in acetonitrile to give the 3′-azido-3′-deoxy-β-ᴅ-ribonucleosides 44a–c and 48a,b via Vorbrüggen coupling reaction. The

• -6-ynofuranoses 88a,b The ʟ-ido- and ᴅ-gluco precursors 88a,b were reacted with trifluoroacetic acid followed by acetic anhydride to afford the 1,2,3,5-tetra-O-acetyl nucleoside analogs 89a and 89b, respectively. Montgomery and Hewson base coupling reaction [60] of 1,2,3,5-tetra-O-acetyl nucleoside

• mixture of E/Z isomers. Further, double bond cleavage of nucleoside 120 followed by benzoylation produced the benzoic acid ester of the hemiacetal analogue 121 which was finally converted into double-headed nucleoside 122 via Vorbrüggen coupling reaction followed by deprotection using methanolic ammonia

Design, synthesis and photophysical properties of novel star-shaped truxene-based heterocycles utilizing ring-closing metathesis, Clauson–Kaas, Van Leusen and Ullmann-type reactions as key tools

• Shakeel Alvi and
• Rashid Ali

Beilstein J. Org. Chem. 2021, 17, 1374–1384, doi:10.3762/bjoc.17.96

• virtue of the Ullmann-type coupling reaction. The tribromotruxene derivative 5 was prepared from the same starting point 1 in three steps (cyclotrimerization, bromination and alkylation) using the literature reported procedures (Scheme 1). Hopefully, these three distinctly different crucial strategies

• the bromination using Br2/CH2Cl2 and then subsequent alkylation followed by Ullmann-type copper-mediated cross-coupling reaction in overall good yield (Scheme 4). On the other hand, imidazole and benzimidazole containing C3-symmetric truxene-based molecules (14 and 16) have also been assembled from

• be inspected from Scheme 7, our journey in this regard stem from the iodination of 2 using H5IO6/I2/H2SO4 in acetic acid–water solvent system to afford the desired triiodotruxene derivative 22 in 50% yield. Furthermore, Suzuki–Miyaura cross-coupling reaction of 22 with 4-formylphenylboronic acid (23