Synthesis of ether lipids: natural compounds and analogues

• Marco Antônio G. B. Gomes,
• Alicia Bauduin,
• Chloé Le Roux,
• Romain Fouinneteau,
• Wilfried Berthe,
• Mathieu Berchel,
• Hélène Couthon and
• Paul-Alain Jaffrès

Beilstein J. Org. Chem. 2023, 19, 1299–1369, doi:10.3762/bjoc.19.96

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

• may provide completely new insights into this issue. In addition, CDC reactions involving ether α-C(sp3)–H bonds are rarely enantioselective, although examples of enantioselectivity have been reported for some similar CDC reactions of amines, and future developments will undoubtedly bridge this

Metal catalyst-free N-allylation/alkylation of imidazole and benzimidazole with Morita–Baylis–Hillman (MBH) alcohols and acetates

• Olfa Mhasni,
• Jalloul Bouajila and
• Farhat Rezgui

Beilstein J. Org. Chem. 2023, 19, 1251–1258, doi:10.3762/bjoc.19.93

• precursors in nucleophilic allylic substitution reactions with amines, presumably due to the perceived poor leaving group ability and low reactivity of the hydroxy group. Interestingly, the direct nucleophilic substitution of the corresponding alcohols has drawn much attention because of the availability of

• investigated the reaction of alcohol 1a [38] and imidazole (2a, 2 equiv), without any catalyst or additive in refluxing methanol, a solvent commonly employed in the conversion of MBH adducts using a variety of amines [39][40]. Our study showed that the imidazole (2a) reacted with alcohol 1a, without any

Radical ligand transfer: a general strategy for radical functionalization

• David T. Nemoto Jr,
• Kang-Jie Bian,
• Shih-Chieh Kao and
• Julian G. West

Beilstein J. Org. Chem. 2023, 19, 1225–1233, doi:10.3762/bjoc.19.90

• much more efficiently in decarboxylative RLT reactions than aliphatic acids [42]. Outside of decarboxylation, X. Peter Zhang recently reported the enantioselective synthesis of allylic amines through coupled HAT and RLT on allylic C–H bonds [45], using a bulky cobalt porphyrin complex developed and

Enabling artificial photosynthesis systems with molecular recycling: A review of photo- and electrochemical methods for regenerating organic sacrificial electron donors

• Grace A. Lowe

Beilstein J. Org. Chem. 2023, 19, 1198–1215, doi:10.3762/bjoc.19.88

• highlights photo- and electrochemical methods for recycling amines and NADH analogues that can be used as electron donors in artificial photosynthesis. Important properties of sacrificial donors and recycling strategies are also discussed. Compounds from other fields, such as redox flow batteries and

• appropriate. EDTA has the highest reported oxidation potential and is the least reducing member of the amines shown (1.41 V vs SCE). Hence, it should only regenerate photooxidized Ru(bpy)3 in aqueous conditions. Unfortunately, Carpenter and co-workers did not measure the oxidation potential of their

• are being developed in non-aqueous solvents. Amines, disulfide-forming thiolates, and NADH derivatives, such as benzimidazoles and acridines, are used as sacrificial donors. Other families of compounds used in other applications such as non-aqueous RFBs, dye-sensitized solar cells, and LOHCs will also

Exploring the role of halogen bonding in iodonium ylides: insights into unexpected reactivity and reaction control

• Carlee A. Montgomery and
• Graham K. Murphy

Beilstein J. Org. Chem. 2023, 19, 1171–1190, doi:10.3762/bjoc.19.86

• ]. They disclosed a reaction between acyclic iodonium ylides (e.g., 31/ I-10) and tertiary amines 32, which produced indoline rings 33 by forging two new C–C bonds between the ylidic carbon and unactivated positions on the amine (Scheme 5). In 2020, they disclosed a more complex variant of this reaction

• that reacted 31 with secondary amines 34, which produced densely functionalized N-heterocycles 35 that incorporated two of the ylide’s β-dicarbonyl motifs (Scheme 6) [123]. Though these reactions were conducted at 70 °C, free carbenes were not involved. Both TEMPO and 1,4-dinitrobenzene inhibited the

• events. Xuan, Li and co-workers further investigated the coupling between iodonium ylides and tertiary amines, and showed that this thermal reaction could instead be initiated by blue light photocatalysis (Scheme 7) [124]. Therein, they investigated the iodoarene motif of the ylide, and while ylide 31

New one-pot synthesis of 4-arylpyrazolo[3,4-b]pyridin-6-ones based on 5-aminopyrazoles and azlactones

• Vladislav Yu. Shuvalov,
• Ekaterina Yu. Vlasova,
• Tatyana Yu. Zheleznova and
• Alexander S. Fisyuk

Beilstein J. Org. Chem. 2023, 19, 1155–1160, doi:10.3762/bjoc.19.83

• domino reaction of enamines with azlactones [22][23][24][25][26][27][28][29][30]. We have previously reported a plausible mechanism of such reactions [22][25]. 1H-Pyrazol-5-amines also enter into similar transformations with azlactones in various solvents. The yields of tetrahydro-1H-pyrazolo[3,4-b

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

• than sacrificial reductants/oxidants employed in conPET (e.g., tetraalkylammonium salts vs trialkylamines), it is worth emphasizing that electrolytes, generally, are chemically innocent to undesired reactions, whereas the byproducts of sacrificed amines may be involved in processes that lower the

• carboxylic acids with amines that typically generate stochiometric amounts of harmful byproducts released [80][81], while simultaneously operating under milder reaction conditions than those applied in transition metal-catalyzed carbonylative amidation protocols [82][83]. Following the same distinct, yet

• . Notably, carbonylative amidation of a borylated aryl bromide to 26d proceeded well, where a Pd-catalyzed carbonylative amidation reaction would be plagued by undesired Suzuki coupling. Several secondary cyclic and acyclic amines, as well as primary amines were successfully employed as amine coupling

CO₂ complexation with cyclodextrins

• Cecilie Høgfeldt Jessen,
• Jesper Bendix,
• Theis Brock Nannestad,
• Heloisa Bordallo,
• Martin Jæger Pedersen,
• Christian Marcus Pedersen and
• Mikael Bols

Beilstein J. Org. Chem. 2023, 19, 1021–1027, doi:10.3762/bjoc.19.78

• infrastructure. One of the characteristics of carbon capture technologies that use amines is the formation of a covalent bond to the CO2 molecule. This bond obviously has to be broken in order to regenerate the material with resulting energy cost [7]. It is therefore logical to explore capture alternatives where

Copper-catalyzed N-arylation of amines with aryliodonium ylides in water

• Kasturi U. Nabar,
• Bhalchandra M. Bhanage and
• Sudam G. Dawande

Beilstein J. Org. Chem. 2023, 19, 1008–1014, doi:10.3762/bjoc.19.76

• .19.76 Abstract Copper sulfate catalyzed an efficient, inexpensive, and environment-friendly protocol that has been developed for N-arylation of amines with 1,3-cyclohexadione-derived aryliodonium ylides in water as a green solvent. Aromatic primary amines substituted with electron-donating as well as

• electron-withdrawing groups on the aryl ring reacted smoothly with iodonium ylides to give the corresponding diarylamines with good to excellent yields. Also, secondary amines underwent N-arylation to deliver tertiary amines with moderate yields. Keywords: amines; arylation; C–N bond formation; iodonium

• strategies for C–N bond formation have been extensively explored by various research groups for the N-arylation of amines. Specifically, seminal contributions by Buchwald [15] and Hartwig [16] involving the use of palladium complexes as catalysts in the presence of either phosphine or diamine ligands for C–N

Synthesis of tetrahydrofuro[3,2-c]pyridines via Pictet–Spengler reaction

• Elena Y. Mendogralo and
• Maxim G. Uchuskin

Beilstein J. Org. Chem. 2023, 19, 991–997, doi:10.3762/bjoc.19.74

• -c]pyridines. From the analysis of the literature data [2][40][41][42][43], we suggested that the interaction of furanic amines with various aldehydes in an acidic media should be accompanied by the formation of the corresponding imine, the generation of the iminium cation, and subsequent Pictet

Aromatic C–H bond functionalization through organocatalyzed asymmetric intermolecular aza-Friedel–Crafts reaction: a recent update

• Anup Biswas

Beilstein J. Org. Chem. 2023, 19, 956–981, doi:10.3762/bjoc.19.72

• the reaction partners in a highly ordered three dimensional transition state through noncovalent interactions (like H-bonding, π–π interactions) thus promoting the stereoselective reaction. Examples of covalent bonding organocatalysts are amines [6][7], N-heterocyclic carbenes [8][9], phosphines [10

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

• compounds. As a result, this review describes the use of various eco-friendly greener protocols to synthesize N-substituted pyrroles. This synthesis involves the reaction of various aliphatic/aromatic primary amines, and sulfonyl primary amines with 2,5-dimethoxytetrahydrofuran in the presence of numerous

• -assisted reactions in water, solvent-free conditions and in other organic solvents. Clauson–Kaas reaction and its mechanism The Clauson–Kaas reaction refers to the synthesis of various N-substituted pyrroles via an acid-catalyzed reaction between aromatic or aliphatic primary amines and 2,5

• temeperatures. In 2000, the application of the Clauson–Kaas reaction was nicely explored by Sonnet et al. [56] for the preparation of diverse pyrrolizinones. The pyrrole derivatives 5 and 7 were synthesized by the classical Clauson–Kaas reaction by refluxing amines 4 or 6 with 2,5-dimethoxytetrahydrofuran (2

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

• pyridine syntheses have relied on the condensation of carbonyl compounds and amines for a very long time [11]. The classical methods for the synthesis of functionalized pyridine include the Hantzsch pyridine synthesis and the Bohlmann–Rahtz synthesis (Scheme 1a and b). Furthermore, alternative

Sulfate radical anion-induced benzylic oxidation of N-(arylsulfonyl)benzylamines to N-arylsulfonylimines

• Joydev K. Laha,
• Pankaj Gupta and
• Amitava Hazra

Beilstein J. Org. Chem. 2023, 19, 771–777, doi:10.3762/bjoc.19.57

• -aryl(benzyl)amines to N-arylimines using K2S2O8 is reported to be problematic, the oxidation of N-(arylsulfonyl)benzylamines to N-arylsulfonylimines using K2S2O8 has been achieved for the first time. The dual role of the sulfate radical anion (SO4·−), including hydrogen atom abstraction (HAT) and

• deliver N-arylsulfonylimines under mild reaction conditions is highly desirable. Previously, we reported a tandem oxidative intramolecular cyclization of N-aryl(benzyl)amines, having an internal nucleophile substituted at the ortho-position in the aniline ring, to nitrogen heterocycles using potassium

• persulfate (K2S2O8) as the exclusive reagent [14]. The mechanistic study revealed that an initial oxidation to an iminium ion could be the key intermediate in the intramolecular cyclization step. In sharp contrast, when N-aryl(benzyl)amines that do not have an ortho-substituted nucleophile in aniline ring

Synthesis of imidazo[1,2-a]pyridine-containing peptidomimetics by tandem of Groebke–Blackburn–Bienaymé and Ugi reactions

• Oleksandr V. Kolomiiets,
• Alexander V. Tsygankov,
• Maryna N. Kornet,
• Aleksander A. Brazhko,
• Vladimir I. Musatov and
• Valentyn A. Chebanov

Beilstein J. Org. Chem. 2023, 19, 727–735, doi:10.3762/bjoc.19.53

• peptidomimetic chain was already described in 2010 [32]. Thus, the corresponding acid components were synthesized with GBB-3CR and used in Ugi and Paserini reactions with various aldehydes, amines (for Ugi) and isocyanides. Moreover, in 2016 [33], an alternative route to use GBB-3CR products in Ugi reaction as

• temperature and the reaction time. After a series of experiments, it was found that stirring the isocyanides 3a–d, heterocyclic acids 4a–c, aldehydes 5a–e, and primary amines 6a–d at 50 °C in methanol for 24–48 hours (depending on the nature of the starting materials) allowed obtaining the Ugi target products

Strategies in the synthesis of dibenzo[b,f]heteropines

• David I. H. Maier,
• Barend C. B. Bezuidenhoudt and
• Charlene Marais

Beilstein J. Org. Chem. 2023, 19, 700–718, doi:10.3762/bjoc.19.51

• '-dibromostilbenes 61 by means of a double Buchwald–Hartwig amination gave yields between 62% and 96% using aniline as the amine reactant (Scheme 13). The reaction proved to be compatible with both aromatic and aliphatic amines and the reaction time varied between 11 and 24 hours. Fluoro, chloro, nitrile, alkyl, and

Synthesis, structure, and properties of switchable cross-conjugated 1,4-diaryl-1,3-butadiynes based on 1,8-bis(dimethylamino)naphthalene

• Semyon V. Tsybulin,
• Ekaterina A. Filatova,
• Alexander F. Pozharskii,
• Valery A. Ozeryanskii and
• Anna V. Gulevskaya

Beilstein J. Org. Chem. 2023, 19, 674–686, doi:10.3762/bjoc.19.49

• singlet oxygen production have been identified in porphyrin-based butadiynes [7][8][9], 1,3-butadiyne-linked oligoporphycenes [10], and 1,3-butadiyne-linked amines [13]. A wide variety of applications was proposed for graphdiynes (2D allotropes of graphene), including electrocatalysts and energy devices

Nucleophile-induced ring contraction in pyrrolo[2,1-c][1,4]benzothiazines: access to pyrrolo[2,1-b][1,3]benzothiazoles

• Ekaterina A. Lystsova,
• Maksim V. Dmitriev,
• Andrey N. Maslivets and
• Ekaterina E. Khramtsova

Beilstein J. Org. Chem. 2023, 19, 646–657, doi:10.3762/bjoc.19.46

• . Such a change in the reaction selectivity could be explained by the influence of a higher nucleophilicity of the examined alkylamines in comparison with benzylamine. Then, we tried to involve less nucleophilic amines to the proposed approach. For these, we examined a reaction of APBTT 1a with aniline

• ). As a result, we have found that the proposed procedure afforded target products 12 in poor to good isolated yields (Scheme 18). We also observed that the nature of the aroyl substituents in substrates 1a–h and aryl substituents in amines 11a–c did not significantly affect the yields of the

• monitoring). Apparently, the reaction of APBTTs 1 with examined amines (benzylamine, alkylamines, arylamines 11) proceeded simultaneously in several directions: initial nucleophilic attack on positions C1, C2 or C4 of compounds 1. The ratio of yields of competitive reaction products depended on the

Transition-metal-catalyzed C–H bond activation as a sustainable strategy for the synthesis of fluorinated molecules: an overview

• Louis Monsigny,
• Floriane Doche and
• Tatiana Besset

Beilstein J. Org. Chem. 2023, 19, 448–473, doi:10.3762/bjoc.19.35

• directing group (namely NHPA and CONHPIP for 53 and 55, respectively), the groups of Chen [71] and Shi [192] independently reported the palladium-catalyzed selective 2,2,2-trifluoroethoxylation of aliphatic amines and amides at the γ and β positions, respectively, using trifluoroethanol as fluorination

Dipeptide analogues of fluorinated aminophosphonic acid sodium salts as moderate competitive inhibitors of cathepsin C

• Karolina Wątroba,
• Małgorzata Pawełczak and
• Marcin Kaźmierczak

Beilstein J. Org. Chem. 2023, 19, 434–439, doi:10.3762/bjoc.19.33

• fluorinated aminophosphonates [23][24] with the simultaneous deprotection of the amino group. The free amines were subjected to kinetic studies to investigate their interaction with cathepsin C. The required steps should be simple and fast, and the conditions of the reactions should be as mild as possible

Group 13 exchange and transborylation in catalysis

• Dominic R. Willcox and
• Stephen P. Thomas

Beilstein J. Org. Chem. 2023, 19, 325–348, doi:10.3762/bjoc.19.28

• dihydride-catalysed the dehydrocoupling of HBpin or H-B-9-BBN with primary and secondary amines (Scheme 22) [84]. The reaction was proposed to proceed by double dehydrocoupling of the amine 87 and aluminium dihydride 88 to give a bisamido aluminium species 89 which underwent Al‒N/B‒H exchange with HBpin to

• mechanistic proposal. Aluminium-catalysed hydroboration of alkenes and the proposed mechanism. Aluminium-catalysed C–H borylation of terminal alkynes and the proposed mechanism. Aluminium-catalysed dehydrocoupling of amines, alcohols, and thiols with H-B-9-BBN or HBpin and the proposed mechanism. Aluminium

An efficient metal-free and catalyst-free C–S/C–O bond-formation strategy: synthesis of pyrazole-conjugated thioamides and amides

• Shubham Sharma,
• Dharmender Singh,
• Sunit Kumar,
• Vaishali,
• Rahul Jamra,
• Naveen Banyal,
• Deepika,
• Chandi C. Malakar and
• Virender Singh

Beilstein J. Org. Chem. 2023, 19, 231–244, doi:10.3762/bjoc.19.22

• -tethered thioamide and amide conjugates. The thioamides were generated by employing a three-component reaction of diverse pyrazole C-3/4/5 carbaldehydes, secondary amines, and elemental sulfur in a single synthetic operation. The advantages of this developed protocol refer to the broad substrate scope

• established the optimal reaction conditions, we explored the generality and the scope of this metal- and catalyst-free approach by employing pyrazole C-3 carbaldehydes 1–4, secondary amines A–E and elemental sulfur as substrates. It was observed that the reaction conditions were compatible with different

• pyrazole-3-carbaldehydes and various secondary amines for the synthesis of pyrazole C-3-tethered thioamides 1A–E and 2–4C with the yield ranging from 53–90% (Scheme 1). Notably, 1-methylpiperazine (E) afforded the product in low yield (53%). The electronic nature of the substituents located at the N-1 and

Inline purification in continuous flow synthesis – opportunities and challenges

• Jorge García-Lacuna and
• Marcus Baumann

Beilstein J. Org. Chem. 2022, 18, 1720–1740, doi:10.3762/bjoc.18.182

• impurity might also contain the same functional group that has affinity to the resin (Scheme 10). QP-SA is a commonly used resin which contains –SO3H groups and can sequester amines, whereby a solution of ammonia in MeOH can be used to release the product [94]. Amine-functionalized resins like A-900 can be

Redox-active molecules as organocatalysts for selective oxidative transformations – an unperceived organocatalysis field

• Elena R. Lopat’eva,
• Igor B. Krylov,
• Dmitry A. Lapshin and
• Alexander O. Terent’ev

Beilstein J. Org. Chem. 2022, 18, 1672–1695, doi:10.3762/bjoc.18.179

• aimed at overviewing the current state-of-art and perspectives of oxidative organocatalysis by redox-active molecules with the emphasis on challenging chemo-, regio- and stereoselective CH-functionalization processes. The catalytic systems based on N-oxyl radicals, amines, thiols, oxaziridines, ketone

• properties of reagents In this section we demonstrate examples of the main types of oxidative processes, in which an organocatalyst does not behave as a redox-active molecule itself but interacts with substrates and thus modulates their redox properties (Scheme 1, type II organocatalysis). Secondary amines

• on carbonyl groups resulting in catalyst deactivation. For example, NHPI catalysis is not compatible with primary and secondary amines [75]. To sum up, the future development of N-oxyl radical catalysis is expected to be associated with discoveries of new structural types of N-oxyl radicals with