Towards an asymmetric β-selective addition of azlactones to allenoates

• Behzad Nasiri,
• Ghaffar Pasdar,
• Paul Zebrowski,
• Katharina Röser,
• David Naderer and
• Mario Waser

Beilstein J. Org. Chem. 2024, 20, 1504–1509, doi:10.3762/bjoc.20.134

• giving access to the acyclic α-amino acid-based amides 6 straightforwardly. Experimental General details 1H and 13C NMR spectra were recorded on a Bruker Avance III 300 MHz spectrometer with a broad band observe probe. All NMR spectra were referenced on the solvent residual peak (CDCl3: δ 7.26 ppm for 1H

Hypervalent iodine-catalyzed amide and alkene coupling enabled by lithium salt activation

• Akanksha Chhikara,
• Fan Wu,
• Navdeep Kaur,
• Prabagar Baskaran,
• Alex M. Nguyen,
• Zhichang Yin,
• Anthony H. Pham and
• Wei Li

Beilstein J. Org. Chem. 2024, 20, 1405–1411, doi:10.3762/bjoc.20.122

• simple lithium salts for hypervalent iodine catalyst activation. The activated hypervalent iodine catalyst allows the intermolecular coupling of soft nucleophiles such as amides onto electronically activated olefins with high regioselectivity. Keywords: amide coupling; hypervalent iodine catalysis

• will then enable soft nucleophiles such as unadorned amides to readily participate in the ensuing olefin addition. In this regard, we wondered if the hypervalent iodine with difluoro ligands could undergo salt metathesis with lithium salts such as LiBF4 or LiPF6 to afford the more reactive cationic

• electrophilicity of the halogen source could be modulated to render different classes of nucleophiles for additions onto olefins in various olefin difunctionalization reactions [48][49][50][51][52]. In particular, we demonstrated that addition of either a Lewis acid or a base could activate amides to couple with

The Ugi4CR as effective tool to access promising anticancer isatin-based α-acetamide carboxamide oxindole hybrids

• Carolina S. Marques,
• Aday González-Bakker and
• José M. Padrón

Beilstein J. Org. Chem. 2024, 20, 1213–1220, doi:10.3762/bjoc.20.104

• structure–activity relationships derived from the GI50 values. The presence of a nitro group at the furan moiety enhanced the activity (8d > 8m). Presumably, the nitro group made 8d the most potent analogue bearing an aromatic amide (8c, 8e, 8g, 8i, 8l–n). For the aliphatic amides, the most potent

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

• , which leads to the formation of a considerable amount of waste [52][53][54]. The BH approach allows a sustainable way for building C–C bonds by coupling abundant and cheap alcohols with ketones, nitriles, esters, and amides [4]. C–C Bond formation via alkylation of ketones with alcohols Several

• the same year, Milstein and co-workers accomplished the α-alkylation of esters, ketones, and amides using alcohols as alkylating agents with a PNP-pincer-supported manganese catalyst [59]. First, the α-alkylation of ketones with benzylic and aliphatic alcohols was studied using Mn11 (1 mol %) as

• catalyst and t-BuOK as a base at 125 °C for 18 h in toluene which afforded up to 95% yield of the desired alkylated ketones (Scheme 28A). Later, the more challenging esters and amides were selectively alkylated with alcohols, however, required higher catalyst loading (5 mol %) and a stoichiometric amount

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

• of amides from 2-alkynylanilines by using TFBen (benzene-1,3,5-triyl triformate) as a CO source, Pd(OAc)2, DPEPhos (bis[(2-diphenylphosphino)phenyl] ether), and DIPEA (N,N-diisopropylethylamine) in MeCN. After 24 h, Pd(OAc)2 and AlCl3 were added to promote a selective cyclization reaction [14]. The

• controllable and regioselective synthesis of indol-3-α-ketoamides and indol-3-amides via the direct double- and monoaminocarbonylation of indole derivatives by using secondary amines [70]. They used Pd(dppf)Cl2 as catalyst system. The indol-3-α-ketoamides were synthesized by adding dppf as ligand, CuI as co

• -catalyst, and LiCl as additive under 40 bar of CO. To make the process regioselective towards indol-3-amides, dppf as ligand, the base (K2CO3), and I2 were added, and the reaction run under a low pressure of CO (1 bar), in addition to the catalyst. Both processes took place well in THF (Scheme 39). In 2013

Direct synthesis of acyl fluorides from carboxylic acids using benzothiazolium reagents

• Lilian M. Maas,
• Alex Haswell,
• Rory Hughes and
• Matthew N. Hopkinson

Beilstein J. Org. Chem. 2024, 20, 921–930, doi:10.3762/bjoc.20.82

• different amides, including dipeptides, under mild and operationally simple conditions in high yields. Mechanistic studies suggest that BT-SCF3 can generate acyl fluorides from carboxylic acids via two distinct pathways, which allows the deoxyfluorinating reagent to be employed in sub-stoichiometric amounts

• . Keywords: acyl fluorides; amides; benzothiazolium salts; carboxylic acids; deoxygenative reactions; Introduction Acyl fluorides are attracting much attention as versatile reagents for different applications in organic synthesis. In addition to their use as sources of fluoride ions, they are most commonly

• acyl fluoride products directly from carboxylic acids. Here, we report the results of this study, which led to the development of a practical and high yielding methodology for the synthesis of acyl fluorides and their subsequent one-pot conversion into amides. Moreover, by virtue of BT-SCF3’s ability

Synthesis and biological profile of 2,3-dihydro[1,3]thiazolo[4,5-b]pyridines, a novel class of acyl-ACP thioesterase inhibitors

• Jens Frackenpohl,
• David M. Barber,
• Guido Bojack,
• Birgit Bollenbach-Wahl,
• Ralf Braun,
• Rahel Getachew,
• Sabine Hohmann,
• Kwang-Yoon Ko,
• Karoline Kurowski,
• Bernd Laber,
• Rebecca L. Mattison,
• Thomas Müller,
• Anna M. Reingruber,
• Dirk Schmutzler and
• Andrea Svejda

Beilstein J. Org. Chem. 2024, 20, 540–551, doi:10.3762/bjoc.20.46

• , 15a, and 15c, the desired 2,3-dihydro[1,3]thiazolo[4,5-b]pyridines 7a–c were prepared in good yield (Table 1, entries 15–17, 59–66% isolated yield), enabling us to investigate the biological profiles as well as the reactions with acyl chlorides to form amides 16a–f (Scheme 2) [27]. These acylations

Ligand effects, solvent cooperation, and large kinetic solvent deuterium isotope effects in gold(I)-catalyzed intramolecular alkene hydroamination

• Ruichen Lan,
• Brock Yager,
• Yoonsun Jee,
• Cynthia S. Day and
• Amanda C. Jones

Beilstein J. Org. Chem. 2024, 20, 479–496, doi:10.3762/bjoc.20.43

• have been masked by the high temperatures and long reaction times of early reports. For example, Widenhoefer engaged carbamates and amides in dioxane at temperatures >80 °C [12][13]. Later work showed that ureas could be engaged at room temperature when a NHC–gold catalyst system was used, outpacing

• nitrogen. Thus, the rate of intramolecular hydroamination is enhanced by a more nucleophilic nitrogen. Another qualitative interpretation is that rates are enhanced by carbonyl basicity. Gas-phase basicity measurements indicate that ureas are more basic than amides [47][50], and here the most Lewis base

• . Carbamates, sulfonamides, and amides display significantly reduced reactivity, if any [56][57]. Titration experiments with MeOH-d4 (further discussion below) reveal that overall reaction rates for urea 1a and carbamate 1b appear to correlated with rates of gold-mediated N–H/D exchange which may further

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

• halides [93][94], bromoalkynes [95], bromoalkanes [96], and pyridyl thioesters [97] (Scheme 26A). Likewise, the Rousseaux group has recently documented the arylation of NHPI esters obtained from cyclopropanecarboxylic acids [98] and malonic acid half amides [99], while the Reisman lab has pioneered an

Copper-promoted C5-selective bromination of 8-aminoquinoline amides with alkyl bromides

• Changdong Shao,
• Chen Ma,
• Li Li,
• Jingyi Liu,
• Yanan Shen,
• Chen Chen,
• Qionglin Yang,
• Tianyi Xu,
• Zhengsong Hu,
• Yuhe Kan and
• Tingting Zhang

Beilstein J. Org. Chem. 2024, 20, 155–161, doi:10.3762/bjoc.20.14

• , China 10.3762/bjoc.20.14 Abstract An efficient and practical method for the synthesis of C5-brominated 8-aminoquinoline amides via a copper-promoted selective bromination of 8-aminoquinoline amides with alkyl bromides was developed. The reaction proceeds smoothly in dimethyl sulfoxide (DMSO) under air

• selective C5-bromination of 8-aminoquinoline amides using carbon tetrabromide and dibromomethane under photo- and electrocatalysis conditions [27][28]. In 2017, Xia and co-workers reported a novel, mild, metal-free, and regioselective bromination of amides, wherein the organic dye eosin Y acted as the

• reaction of 8-aminoquinoline amides using activated and unactivated alkyl bromides as the bromine source (Scheme 1, reaction 4). Results and Discussion At the beginning of this investigation, N-(quinolin-8-yl)benzamide (1a) and ethyl bromoacetate (2a) were selected as model substrates to screen the

Synthesis of N-acyl carbazoles, phenoxazines and acridines from cyclic diaryliodonium salts

• Nils Clamor,
• Mattis Damrath,
• Thomas J. Kuczmera,
• Daniel Duvinage and
• Boris J. Nachtsheim

Beilstein J. Org. Chem. 2024, 20, 12–16, doi:10.3762/bjoc.20.2

• Bremen, Germany 10.3762/bjoc.20.2 Abstract N-Acyl carbazoles can be efficiently produced through a single-step process using amides and cyclic diaryliodonium triflates. This convenient reaction is facilitated by copper iodide in p-xylene, using the commonly found activating ligand diglyme. We have

• tested this method with a wide range of amides and iodonium triflates, proving its versatility with numerous substrates. Beyond carbazoles, we also produced a variety of other N-heterocycles, such as acridines, phenoxazines, or phenazines, showcasing the robustness of our technique. In a broader sense

• efficient method to synthesize N-acyl carbazoles from readily available iodolium salt and amides via a ring-opening/intramolecular coupling cascade (Scheme 1c) [20][21][22][23][24][25][26][27][28][29][30]. Our group recently explored principle synthetic pathways of hetero- and carbocyclic 5- and 6-membered

Synthetic approach to 2-alkyl-4-quinolones and 2-alkyl-4-quinolone-3-carboxamides based on common β-keto amide precursors

• Yordanka Mollova-Sapundzhieva,
• Plamen Angelov,
• Danail Georgiev and
• Pavel Yanev

Beilstein J. Org. Chem. 2023, 19, 1804–1810, doi:10.3762/bjoc.19.132

• ., 4000 Plovdiv, Bulgaria 10.3762/bjoc.19.132 Abstract β-Keto amides were used as convenient precursors to both 2-alkyl-4-quinolones and 2-alkyl-4-quinolone-3-carboxamides. The utility of this approach is demonstrated with the synthesis of fourteen novel and four known quinolone derivatives, including

• natural products of microbial origin such as HHQ and its C5-congener. Two compounds with high activity against S. aureus have been identified among the newly obtained quinolones, with MICs ≤ 3.12 and ≤ 6.25 µg/mL, respectively. Keywords: antibacterial; β-keto amides; enaminones; 4-quinolones; quorum

• substituents at the C-2 position. As a way of expanding the scope of this methodology, we resorted to the α-C-acylation of β-enamino amides, a reliable reaction, the utility of which we have already demonstrated in other contexts [62][63]. Results and Discussion As the starting point of our synthetic

Benzoimidazolium-derived dimeric and hydride n-dopants for organic electron-transport materials: impact of substitution on structures, electrochemistry, and reactivity

• Swagat K. Mohapatra,
• Khaled Al Kurdi,
• Samik Jhulki,
• Georgii Bogdanov,
• John Bacsa,
• Maxwell Conte,
• Tatiana V. Timofeeva,
• Seth R. Marder and
• Stephen Barlow

Beilstein J. Org. Chem. 2023, 19, 1651–1663, doi:10.3762/bjoc.19.121

• more soluble than the iodides in THF, so were reductively dimerized to 12 in THF using Na:Hg, although reduction of 1i+PF6− failed to afford 1i2. As we have noted before for other 12 species, amides (V, Scheme 1) are encountered as both byproducts of dimer synthesis and dimer decomposition products [14

N-Sulfenylsuccinimide/phthalimide: an alternative sulfenylating reagent in organic transformations

• Fatemeh Doraghi,
• Seyedeh Pegah Aledavoud,
• Mehdi Ghanbarlou,
• Bagher Larijani and
• Mohammad Mahdavi

Beilstein J. Org. Chem. 2023, 19, 1471–1502, doi:10.3762/bjoc.19.106

• preparation of thioesters, acyl disulfides, ketones, and amides starting from N-thiohydroxy succinimide esters (NTSEs) 1’’’, which can serve as the acylthiolating and acylating source (Scheme 32) [65]. First, they synthesized a series of N-thiohydroxy succinimide esters by treating potassium thiolates with N

• selectively transfer the acyl or acylthio moieties. Arylboronic acids 74 and amines 76 were suitable for the acyl transfer and led to ketones 78 and amides 80 as the desired products. While, Grignard reagents 75 and thiols 77 acted as soft nucleophiles and resulted in thioesters 79 and acyl disulfides 81

• intermediate led to intramolecular cyclization. In 2020, electrophilic cyclization of allylic amides 134 using N-(phenylthio)succinimide 1 in the presence of camphorsulfonic acid (CSA) as a Brønsted acid and tetrabutylammonium chloride (TBAC) led to 5-[(phenylthio)methyl]oxazoline scaffolds 135 (Scheme 57) [89

α-(Aminomethyl)acrylates as acceptors in radical–polar crossover 1,4-additions of dialkylzincs: insights into enolate formation and trapping

• Angel Palillero-Cisneros,
• Paola G. Gordillo-Guerra,
• Fernando García-Alvarez,
• Olivier Jackowski,
• Franck Ferreira,
• Fabrice Chemla,
• Joel L. Terán and
• Alejandro Perez-Luna

Beilstein J. Org. Chem. 2023, 19, 1443–1451, doi:10.3762/bjoc.19.103

• allylation of lithium (trimethylsilyl)amides prepared in situ from the parent amines by a lithiation/silylation/lithiation sequence (Table 1). Using this protocol, α-(aminomethyl)acrylates 5 and 6 derived from benzhydrylamine and aniline were prepared in high yields (Table 1, entries 1 and 2). The procedure

Application of N-heterocyclic carbene–Cu(I) complexes as catalysts in organic synthesis: a review

• Nosheen Beig,
• Varsha Goyal and
• Raj K. Bansal

Beilstein J. Org. Chem. 2023, 19, 1408–1442, doi:10.3762/bjoc.19.102

• the NHC–CuN(SiMe3)2 complexes 42, 45, and 48, respectively. All synthesized complexes were characterized by TGA to explain their thermal behavior. The impact of the N-allyl substituent and backbone character on volatility and thermal stability of the copper amides were investigated and it was found

Non-noble metal-catalyzed cross-dehydrogenation coupling (CDC) involving ether α-C(sp³)–H to construct C–C bonds

• Hui Yu and
• Feng Xu

Beilstein J. Org. Chem. 2023, 19, 1259–1288, doi:10.3762/bjoc.19.94

• presence of TBHP as oxidant (Scheme 7a) [56]. Various α-ether-alkylated aminocarbonyl compounds were synthesized via this method and it could be extended to various α-amino ketones, α-amino esters, and α-amino amides. The mechanism of these coupling reactions is very similar and is initiated by the attack

Photoredox catalysis harvesting multiple photon or electrochemical energies

• Mattia Lepori,
• Simon Schmid and
• Joshua P. Barham

Beilstein J. Org. Chem. 2023, 19, 1055–1145, doi:10.3762/bjoc.19.81

Clauson–Kaas pyrrole synthesis using diverse catalysts: a transition from conventional to greener approach

• Dileep Kumar Singh and
• Rajesh Kumar

Beilstein J. Org. Chem. 2023, 19, 928–955, doi:10.3762/bjoc.19.71

• (P2O5) as a catalyst for the conversion of various aliphatic amines, aromatic amines, sulfonamides and primary amides into N-substituted pyrroles (Scheme 5). These pyrroles were synthesized in 46–100% yields by the modified Clauson–Kaas reaction between amines 10 and 2,5-DMTHF (2) in the presence of

• their expectation thus, they synthesized 13 derivatives of pyrroles in good yields in short reaction times (10–45 min). It has been observed that aromatic amines and amides take a longer time compared to the primary amines and sulfonamides. In another study, Rochais et al. [59] reported in 2004 the

• acids/sulfonates from various primary sulfonamides via sulfonylpyrroles. First, various sulfonylpyrroles 69 were prepared from primary sulfonamides 68 by reaction with 2,5-DMTHF (2) using two methods as shown in Scheme 33. In method 1, amides 68 and 2 were heated in toluene at 100 °C for 30–60 min in

Asymmetric tandem conjugate addition and reaction with carbocations on acylimidazole Michael acceptors

• Brigita Mudráková,
• Renata Marcia de Figueiredo,
• Jean-Marc Campagne and
• Radovan Šebesta

Beilstein J. Org. Chem. 2023, 19, 881–888, doi:10.3762/bjoc.19.65

• organoboron reagents were realized [12]. Also, in terms of suitable Michael acceptors as substrates, unsaturated ketones, aldehydes, esters, thioesters, amides, alkenyl heterocycles and enoyl heterocycles became viable for conjugate additions. The maturity and robustness of this methodology is documented by

• , imines, other Michael acceptors, or alkyl halides. Our group is developing trapping of metal enolates with stabilized carbocations and could show that magnesium enolates generated from enones [22], unsaturated amides [23], or heterocycles reacted with tropylium, dithiolylium or flavylium cations [24

Pyridine C(sp²)–H bond functionalization under transition-metal and rare earth metal catalysis

• Haritha Sindhe,
• Malladi Mounika Reddy,
• Karthikeyan Rajkumar,
• Akshay Kamble,
• Amardeep Singh,
• Anand Kumar and
• Satyasheel Sharma

Beilstein J. Org. Chem. 2023, 19, 820–863, doi:10.3762/bjoc.19.62

• serve as bioisostere for aromatic rings, amines, amides, and N-containing heterocycles. Due to the aforementioned qualities, numerous U.S. FDA-approved medications have pyridine scaffolds in their molecules (Figure 1). In this context, the synthesis of the pyridine motif is always there in trend. Many

Eschenmoser coupling reactions starting from primary thioamides. When do they work and when not?

• Lukáš Marek,
• Jiří Váňa,
• Jan Svoboda and
• Jiří Hanusek

Beilstein J. Org. Chem. 2023, 19, 808–819, doi:10.3762/bjoc.19.61

• ). α-Bromophenylacetic acid amides (4a,b) were prepared from 2-bromo-2-phenylacetyl chloride [38] and the corresponding amine in DCM or toluene at reduced temperature (see Supporting Information File 1). Thiobenzamides and thiobenzanilides were prepared by magnesium chloride-catalyzed thiolysis of

• commercially available benzonitriles [39] or by thionation of the corresponding N-substituted amides [40] using pyridine–P4S10 as sulfurization agent. Other chemicals and solvents were purchased from Acros Organics, Sigma-Aldrich, and Fluorochem and were used as received. 1H and 13C (APT) NMR spectra were

• theory in N,N-dimethylformamide (SMD). Extended version of Figure 2 involving energies of final products can be found in Supporting Information File 1. Eschenmoser coupling reaction between 3-substituted oxindoles and thioamides. Possible reactions of α-haloketones, esters and amides with primary

Palladium-catalyzed enantioselective three-component synthesis of α-arylglycine derivatives from glyoxylic acid, sulfonamides and aryltrifluoroborates

• Bastian Jakob,
• Nico Schneider,
• Luca Gengenbach and
• Georg Manolikakes

Beilstein J. Org. Chem. 2023, 19, 719–726, doi:10.3762/bjoc.19.52

• palladium-catalyzed three-component reactions between arylboronic or carboxylic acids, amides or sulfonamides and different aldehyde components as attractive and broadly applicable alternative to the classical Petasis borono-Mannich reaction (Scheme 1b) [17][18][19][20][21]. Recently, we were able to extend

Enolates ambushed – asymmetric tandem conjugate addition and subsequent enolate trapping with conventional and less traditional electrophiles

• Péter Kisszékelyi and
• Radovan Šebesta

Beilstein J. Org. Chem. 2023, 19, 593–634, doi:10.3762/bjoc.19.44

• developed a Lewis acid-promoted conjugate addition to unreactive Michael acceptors such as amides or vinyl heterocycles [60]. Trimethylsilyl triflate or boron trifluoride-activated unsaturated amides underwent highly efficient and enantioselective addition of Grignard reagents. When this methodology was

• alkenyl heteroarenes [61]. The aza-enolates were trapped with various Michael acceptors such as unsaturated ketones, esters, and amides (Scheme 25) [62]. The authors noted a strong substrate dependence of this process. The trapping reaction worked best with benzoxazole-derived substrate, while thiazole

• Lewis acid-mediated generation of magnesium enolates in the trapping reactions with carbocations. Indeed, unsaturated amides, alkenyl heterocycles, or even unsaturated carboxylic acids successfully participated in this process affording structurally interesting products (Scheme 26) [63]. Apart from

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

• norbornene derivatives 15 using imides 27 and tetraarylborates 28 (Scheme 5) [37]. The method utilizes C–N bond activation to trigger the reaction. The authors demonstrated a broad reaction scope. Electron-deficient amides were shown to perform worse than their electron-rich counterparts with the p

• investigated the Ru-catalyzed ring-opening/lactamization of azabenzonorbornadiene derivatives 30 with arylamides 116 (Scheme 21) [64]. Weinreb amides outperformed other arylamides, likely serving as a better directing group for the initial aryl-C–H activation. While the scope of functionalized aryl Weinreb

• amides was quite wide, including different EWGs and EDGs, as well as heterocycles, ortho-substitution was not tolerated. The authors applied the methodology for the synthesis of biologically important benzo[c]phenanthridine derivatives 117. Through methylation and subsequent aromatization of the