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

• 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

• reported [53]. In 2015, Kang and co-workers described a FeCl2-catalyzed tandem cyclization/cross-coupling reaction of alkyl iodides 1 with aryl Grignard reagents 2 to give arylmethyl-substituted pyrrolidines and tetrahydrofurans 3 in poor to excellent yield (Scheme 3) [54]. The concept of alkyl halide

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

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

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

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

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

• -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

• components, the concept of creating one-component OSCs appeared [54]. Following this strategy, isoindigo was used as platform for the synthesis of compound 35a, combining acceptor (perylene diimide) and donor (polythiophene) fragments in the structure. Both polymers were obtained using the Stille cross

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

• ) and 5′-O-DMTr-protected N4-(dimethylaminomethylene)-2′-deoxycytidine (134a–d) by using Sonogashira cross coupling reaction between the propargylated nucleobases, i.e., 1-propargylthymine, N4-acetyl-1-propargylcytosine, N6-benzoyl-9-propargyladenine, and N2-isobutyryl-9-propargylguanine (13a–d) and 5

• -dimethoxytrityl-5-(4-(thymin-1-yl)phenyl)ethynyl-2′-deoxyuridine (141) were synthesized via a Sonogashira cross coupling reaction between the N1-(3/4-iodophenyl)thymine derivatives 136c and 136d and 2′-deoxy-5-ethynyluridine derivative 139 (Scheme 35) [75]. All four nucleoside monomers were converted into

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

• 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

• to the pyrrole-based C3-symmetric truxene derivative 6. Synthesis of tripyrrolotruxene 6 via cyclotrimerization and RCM as crucial steps. Synthesis of star-shaped molecule 6 utilizing the Clauson–Kaas pyrrole strategy. Synthesis of truxene derivative 6 involving Ullmann-type cross-coupling reaction

N-tert-Butanesulfinyl imines in the asymmetric synthesis of nitrogen-containing heterocycles

• Joseane A. Mendes,
• Paulo R. R. Costa,
• Miguel Yus,
• Francisco Foubelo and
• Camilla D. Buarque

Beilstein J. Org. Chem. 2021, 17, 1096–1140, doi:10.3762/bjoc.17.86

Synthetic reactions driven by electron-donor–acceptor (EDA) complexes

• Zhonglie Yang,
• Yutong Liu,
• Kun Cao,
• Xiaobin Zhang,
• Hezhong Jiang and
• Jiahong Li

Beilstein J. Org. Chem. 2021, 17, 771–799, doi:10.3762/bjoc.17.67

• pathways has the advantages of mild reaction conditions and a high tolerance to functional groups, which can be exploited for artificial syntheses of biological macromolecules. In 2017, Miyake and colleagues [54] designed a type of C–S cross-coupling reaction initiated by an EDA complex promoted by visible

Amino- and polyaminophthalazin-1(2H)-ones: synthesis, coordination properties, and biological activity

• Zbigniew Malinowski,
• Emilia Fornal,
• Agata Sumara,
• Renata Kontek,
• Karol Bukowski,
• Beata Pasternak,
• Dariusz Sroczyński,
• Joachim Kusz,
• Magdalena Małecka and
• Monika Nowak

Beilstein J. Org. Chem. 2021, 17, 558–568, doi:10.3762/bjoc.17.50

• Information File 1). In the next step, the bromolactams 3 were subjected to a thermal palladium cross-coupling reaction with various amines and polyamines. To optimize the reaction conditions, we investigated the reaction of 4-bromo-2-methylphthalazin-1(2H)-one (3a) with morpholine as the model substrates

• cross-coupling reaction. To confirm this idea, we carried out an experiment in which to the in situ-generated (BINAP)Pd complex (Pd2(dba)3/rac-BINAP or (R)-BINAP; 15:15 mol %) morpholine was added prior to the addition of lactam 3a. As a result, we obtained the target 4-(morpholin-4-yl) derivative 5a in

Progress in the total synthesis of inthomycins

• Bidyut Kumar Senapati

Beilstein J. Org. Chem. 2021, 17, 58–82, doi:10.3762/bjoc.17.7

• step due to its high instability. Finally, the Stille cross-coupling reaction between vinylstannane 24 and dienyl iodide (rac)-20 using PdCl2(CN)2 and triethylamine in DMF produced racemic inthomycin A (or phthoxazolin A) (rac)-1 in 22% yield (Scheme 1). Although the overall yield of this route was

Deoxyfluorination of acyl fluorides to trifluoromethyl compounds by FLUOLEAD^®/Olah’s reagent under solvent-free conditions

• Yumeng Liang,
• Akihito Taya,
• Zhengyu Zhao,
• Norimichi Saito and
• Norio Shibata

Beilstein J. Org. Chem. 2020, 16, 3052–3058, doi:10.3762/bjoc.16.254

• fluorides. Acyl fluorides, which are one type of acyl halides, show distinct stability in the presence of moisture, indicating their suitable reactivity only in selected conditions [19]. In addition to our direct cross-coupling reaction method, several useful synthetic methods for the formation of acyl

• developed various efficient methodologies for the electrophilic [14][15], nucleophilic [16], and radical [17] trifluoromethylation reactions for more than a decade. In recent years, we also reported the direct introduction of an acyl fluoride unit into aromatic compounds by the Pd-catalyzed cross-coupling

• reaction of aryl, vinyl, and heteroaryl iodides with 2-(difluoromethoxy)-5-nitropyridine [18]. A wide variety of acyl fluorides were efficiently obtained in high yields. We were fascinated by the synthetic versatility of acyl fluorides [19] to form other functional groups during our research on acyl

Changed reactivity of secondary hydroxy groups in C8-modified adenosine – lessons learned from silylation

• Jennifer Frommer and
• Sabine Müller

Beilstein J. Org. Chem. 2020, 16, 2854–2861, doi:10.3762/bjoc.16.234

• phosphoramidite building block 9 (Scheme 2). Results and Discussion Typically, the synthesis of C8-alkynyl derivatives relies on C8-bromoadenosine as reactant for the Sonogashira cross-coupling reaction to introduce the amino linker N-(propyn-2-yl)-6-(trifluoroacetamido)hexanamide (L) bearing an alkynyl moiety

Synthesis and characterization of S,N-heterotetracenes

• Astrid Vogt,
• Florian Henne,
• Christoph Wetzel,
• Elena Mena-Osteritz and
• Peter Bäuerle

Beilstein J. Org. Chem. 2020, 16, 2636–2644, doi:10.3762/bjoc.16.214

• , gave the corresponding β-brominated thienothiophene 4 in 91% yield [6]. Compound 4 was selectively brominated in α-position by using NBS in DMF at room temperature to give dibrominated thienothiophene 5 in 92% yield which was coupled in a Negishi-type cross-coupling reaction with zincated 2,3

• the azide route. The synthesis started from the above mentioned brominated thieno[3,2-b]thiophene 3, which was coupled with zincated 2,3-dibromothiophene 6 in a Negishi-type cross-coupling reaction with Pd(dppf)Cl2 as catalyst to give thiophene-substituted thienothiophene 10 in 72% yield. In the next

Synthetic approaches to bowl-shaped π-conjugated sumanene and its congeners

• Shakeel Alvi and
• Rashid Ali

Beilstein J. Org. Chem. 2020, 16, 2212–2259, doi:10.3762/bjoc.16.186

• % yield. Next, the methyl substituents were introduced at the position of the carbonyl groups of 23 to generate the methyl-substituted olefin derivative 25 via alkenyl phosphates 24 by means of three-fold cross-coupling reaction with methylmagnesium iodide in THF. Finally, during the tandem ROM–RCM, they

• Suzuki–Miyaura cross-coupling reaction of bromosumanene 82 under microwave reaction conditions. Whereas another route involves the Ni-catalyzed aryl–aryl homo-coupling between the two molecules of iodosumanene 79 [51][52]. Moreover, the bissumanenyl 92, which is thought to be chiral because of the two

• , very few reports could be found for selective functionalization at the peripheral carbons because of difficulties arose during their synthesis. In this regard, Toda et al. in 2017 have successfully synthesized 2,3,5,6,8,9-hexaarylsumanene derivatives 95a–h utilizing a Suzuki–Miyaura cross-coupling

Azo-dimethylaminopyridine-functionalized Ni(II)-porphyrin as a photoswitchable nucleophilic catalyst

• Jannis Ludwig,
• Julian Helberg,
• Hendrik Zipse and
• Rainer Herges

Beilstein J. Org. Chem. 2020, 16, 2119–2126, doi:10.3762/bjoc.16.179

• the Suzuki cross-coupling reaction published for a similar system [30], decomposition products and only 25% yield were obtained. Optimization by lowering the reaction temperature increased the yield to 91% (Scheme 1). Switching properties of porphyrin 1 Preliminary investigations on the photochemical

Synergy between supported ionic liquid-like phases and immobilized palladium N-heterocyclic carbene–phosphine complexes for the Negishi reaction under flow conditions

• Edgar Peris,
• Raúl Porcar,
• María Macia,
• Jesús Alcázar,
• Eduardo García-Verdugo and
• Santiago V. Luis

Beilstein J. Org. Chem. 2020, 16, 1924–1935, doi:10.3762/bjoc.16.159

• -bromobenzoate (6) to form methyl 4-benzylbenzoate (7) was used to evaluate the activity of the palladium catalysts on polymer support (Scheme 2). The Negishi reaction is a potent cross-coupling reaction in organic chemistry. Notably, it has much value for the synthesis of fine chemicals and medicinal drugs [22

One-pot and metal-free synthesis of 3-arylated-4-nitrophenols via polyfunctionalized cyclohexanones from β-nitrostyrenes

• Haruyasu Asahara,
• Minami Hiraishi and
• Nagatoshi Nishiwaki

Beilstein J. Org. Chem. 2020, 16, 1830–1836, doi:10.3762/bjoc.16.150

• group hinder the electrophilic modification at the 3-position. Generally, the aryl group is introduced by a Suzuki–Miyaura cross-coupling reaction [4][5], for which 3-bromo-4-nitrophenol must be prepared by the nitration of 3-bromophenol [6][7]. An alternative approach is the nitration of 3-arylphenol