Recent advances in oxidative radical difunctionalization of N-arylacrylamides enabled by carbon radical reagents

• Jiangfei Chen,
• Yi-Lin Qu,
• Ming Yuan,
• Xiang-Mei Wu,
• Heng-Pei Jiang,
• Ying Fu and
• Shengrong Guo

Beilstein J. Org. Chem. 2025, 21, 1207–1271, doi:10.3762/bjoc.21.98

Synthesis of fluorinated acid-functionalized, electron-rich nickel porphyrins

• Mike Brockmann,
• Jonas Lobbel,
• Lara Unterriker and
• Rainer Herges

Beilstein J. Org. Chem. 2024, 20, 2954–2958, doi:10.3762/bjoc.20.248

• . After metalation with Ni(acac)2 and hydrolysis electron-rich porphyrins were obtained, that are equipped with covalently attached long chain acid substituents. The target compounds have potential applications in catalysis, sensing, and materials science. The fluorinated aliphatic carboxylic acids (TfO

• ; perfluorinated aliphatic carboxylic acids; porphyrin synthesis; Introduction Metal porphyrins are prosthetic groups in a number of essential biomolecules, including hemoglobin, chlorophyll, and cytochromes, supporting processes such as oxygen transport, photosynthesis, and electron transfer [1][2][3][4][5

The scent gland composition of the Mangshan pit viper, Protobothrops mangshanensis

• Jonas Holste,
• Paul Weldon,
• Donald Boyer and
• Stefan Schulz

Beilstein J. Org. Chem. 2024, 20, 2644–2654, doi:10.3762/bjoc.20.222

• ., B and B’ here. The molecular ion and one of the fragment ions both increased by 14 Da, respectively, within the series. This suggests that A–F have the same core structure, but different chain lengths. Although the mass spectra showed small ions m/z 60 and 73 characteristic for aliphatic carboxylic

• acids, comparison with in-house and other spectral libraries revealed no close match with known compounds. High-resolution EI gas chromatography (HREI–GC–MS) of compound D suggested a molecular formula of C14H26O2 (m/z 226.18962 [M]+, calcd 226.19328), and two double-bond equivalents. The characteristic

Electrophotochemical metal-catalyzed synthesis of alkylnitriles from simple aliphatic carboxylic acids

• Yukang Wang,
• Yan Yao and
• Niankai Fu

Beilstein J. Org. Chem. 2024, 20, 1497–1503, doi:10.3762/bjoc.20.133

• .20.133 Abstract We report a practical and sustainable electrophotochemical metal-catalyzed protocol for decarboxylative cyanation of simple aliphatic carboxylic acids. This environmentally friendly method features easy availability of substrates, broad functional group compatibility, and directly

• converts a diverse range of aliphatic carboxylic acids including primary and tertiary alkyl acids into synthetically versatile alkylnitriles without using chemical oxidants or costly cyanating reagents under mild reaction conditions. Keywords: aliphatic carboxylic acids; alkylnitriles; electroorganic

• ][18]. Owing to the prevalence of aliphatic carboxylic acids in biomass and natural products, decarboxylative cyanation represents one of the most straightforward and attractive approaches to accessing alkylnitriles [19][20]. As an elegant example, Barton demonstrated the application of redox-active

Generation of alkyl and acyl radicals by visible-light photoredox catalysis: direct activation of C–O bonds in organic transformations

• Mithu Roy,
• Bitan Sardar,
• Itu Mallick and
• Dipankar Srimani

Beilstein J. Org. Chem. 2024, 20, 1348–1375, doi:10.3762/bjoc.20.119

• [28] introduced the photoredox-catalyzed hydroacylation of styrene derivatives via deoxygenation of challenging aliphatic carboxylic acids (Scheme 1). The deoxygenation was promoted by phosphine reagents to form acyl radicals. The acyl radicals reacted with the C=C bond and formed the expected product

• in a satisfactory yield. Various hydrocinnamic acids having electron-donating and electron-withdrawing substituents provided the targeted products 3a–c in good yield. Heterocycles containing carboxylic acids also provided the products 3d–g in moderate to good yield. Aliphatic carboxylic acids, under

• presence of alkene, alkyne, halogen, and ether moieties. N-Boc-protected amines and esters also provided a good to excellent yield. Unfortunately, α,β-unsaturated carboxylic acids and aliphatic carboxylic acids were ineffective using this method. In 2024, Liu and co-workers [31] introduced a photocatalytic

Auxiliary strategy for the general and practical synthesis of diaryliodonium(III) salts with diverse organocarboxylate counterions

• Naoki Miyamoto,
• Daichi Koseki,
• Kohei Sumida,
• Elghareeb E. Elboray,
• Naoko Takenaga,
• Ravi Kumar and
• Toshifumi Dohi

Beilstein J. Org. Chem. 2024, 20, 1020–1028, doi:10.3762/bjoc.20.90

• to develop an alternative approach by reacting iodosobenzene (5a) with a range of aromatic and aliphatic carboxylic acids 6a–i to form phenyl(TMP)iodonium(III) carboxylates 3ae, 7aa–ai (Scheme 5A). The reaction between benzoic acids (6a, 6b) and heteroaromatic carboxylic acids (6c, 6d) proceeded

• smoothly under the set conditions to form the corresponding phenyl(TMP)iodonium(III) carboxylates 7aa–ad in high yield. Additionally, a range of aliphatic carboxylic acids such as acetic acid (6e), pivalic acid (6f), cyclohexanecarboxylic acid (6g), and aliphatic carboxylic acid with acidic α-proton (6h

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

• substituents could be present at the ortho-, meta- or para-positions. The heteroaromatic acyl fluoride 2h could be prepared efficiently while deoxyfluorination of representative olefinic and aliphatic carboxylic acids proceeded smoothly, affording cinnamoyl and decanoyl acyl fluorides 2i and 2j in 80% and 89

• functionalisation chemistry such as coupling reactions (5g, 5m, 5n). Heteroaromatic (5o) and aliphatic carboxylic acids (5j, 5p, 5q) also reacted smoothly under the optimised conditions. As demonstrated by the efficient formation of amide 5q in 84% yield, the process is tolerant of significant steric bulk at the

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

• desaturation of aliphatic carboxylic acids [83]. Initiation by metal catalysts and stoichiometric reductants The activation of NHPI esters under transition metal catalysis without the need of light is also feasible, and generally, two types of coupling reactions can be envisioned. On one hand, the

Recent advancements in iodide/phosphine-mediated photoredox radical reactions

• Tinglan Liu,
• Yu Zhou,
• Junhong Tang and
• Chengming Wang

Beilstein J. Org. Chem. 2023, 19, 1785–1803, doi:10.3762/bjoc.19.131

• compatibility and efficiency of a diverse range of redox-active esters 3, deriving from various aliphatic carboxylic acids (including primary, secondary, and tertiary acids), as well as α-amino acids. Impressively, these redox-active esters exhibited exceptional compatibility, high effectiveness, and remarkable

Visible-light-induced nickel-catalyzed α-hydroxytrifluoroethylation of alkyl carboxylic acids: Access to trifluoromethyl alkyl acyloins

• Feng Chen,
• Xiu-Hua Xu,
• Zeng-Hao Chen,
• Yue Chen and
• Feng-Ling Qing

Beilstein J. Org. Chem. 2023, 19, 1372–1378, doi:10.3762/bjoc.19.98

• the substrate scope of this photoinduced nickel-catalyzed cross coupling reaction. As illustrated in Scheme 2, a broad array of aliphatic carboxylic acids reacted smoothly in this protocol, providing the corresponding trifluoromethyl aliphatic acyloins in moderate to excellent yields. This mild

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

NaI/PPh₃-catalyzed visible-light-mediated decarboxylative radical cascade cyclization of N-arylacrylamides for the efficient synthesis of quaternary oxindoles

• Dan Liu,
• Yue Zhao and
• Frederic W. Patureau

Beilstein J. Org. Chem. 2023, 19, 57–65, doi:10.3762/bjoc.19.5

• -membered ring structure 3ra could be successfully isolated with a good yield (66%). A number of alkyl radical precursors were then synthesized and evaluated in the reaction (Scheme 3). We found that redox-active esters derived from primary, secondary, and tertiary aliphatic carboxylic acids were all

Recent advances in transition-metal-catalyzed incorporation of fluorine-containing groups

• Xiaowei Li,
• Xiaolin Shi,
• Xiangqian Li and
• Dayong Shi

Beilstein J. Org. Chem. 2019, 15, 2213–2270, doi:10.3762/bjoc.15.218

• decarboxylative trifluoromethylation of various primary and secondary aliphatic carboxylic acids. With AgNO3 as a catalyst, (bpy)Cu(CF3)3 (bpy = 2,2’-bipyridine) as a CF3 source and K2S2O8 as an oxidant, aliphatic carboxylic acids were converted to the corresponding trifluoromethylated products in good yields

• (Scheme 60). Also, mechanistic studies, a radical clock experiment, revealed the intermediacy of −Cu(CF3)3Me, which undergoes reductive elimination and subsequent oxidation to give the active species Cu(CF3)2. Meanwhile, aliphatic carboxylic acids give the corresponding alkyl radicals via Ag(II)-mediated

• oxidative decarboxylation. Then, Cu(CF3)2 provides a CF3 group to alkyl radicals to obtain the final product. Very recently, MacMillan et al. [120] discovered an efficient approach to the decarboxylative trifluoromethylation of aliphatic carboxylic acids via the combination of photoredox and copper

Copper(I)-catalyzed tandem reaction: synthesis of 1,4-disubstituted 1,2,3-triazoles from alkyl diacyl peroxides, azidotrimethylsilane, and alkynes

• Muhammad Israr,
• Changqing Ye,
• Munira Taj Muhammad,
• Yajun Li and
• Hongli Bao

Beilstein J. Org. Chem. 2018, 14, 2916–2922, doi:10.3762/bjoc.14.270

• reagents and enriched organic azide sources for CuAAC reaction are still highly required. Herein, we report a novel CuAAC reaction, using aliphatic carboxylic acids as the alkyl source [36], and TMSN3 as the azide source (Scheme 1b). Because TMSN3 can react with alkynes to form the CuAAC reaction product

• [32][33][34][35], there is one significant challenge of this method that need to be emphasized: how to control the reaction to generate the alkyl azides from aliphatic carboxylic acids and TMSN3, before TMSN3 directly reacting with alkynes. Results and Discussion Based on our unpublished work, we

• found that alkyl azide has always appeared as a side product when the reaction involved TMSN3 and alkyl diacyl peroxide, easily available compounds derived from aliphatic carboxylic acids. With this information in mind, initially, we started our investigation with phenylacetylene (1a), commercially

Hypervalent iodine(III)-mediated decarboxylative acetoxylation at tertiary and benzylic carbon centers

• Kensuke Kiyokawa,
• Daichi Okumatsu and
• Satoshi Minakata

Beilstein J. Org. Chem. 2018, 14, 1046–1050, doi:10.3762/bjoc.14.92

• –O bond formation has received considerably less attention, even though it represents a promising strategy for the synthesis of valuable alcohol derivatives. One of the classical methods for the decarboxylative C–O bond formation of aliphatic carboxylic acids involves the use of stoichiometric

Development of a method for the synthesis of 2,4,5-trisubstituted oxazoles composed of carboxylic acid, amino acid, and boronic acid

• Kohei Yamada,
• Naoto Kamimura and
• Munetaka Kunishima

Beilstein J. Org. Chem. 2017, 13, 1478–1485, doi:10.3762/bjoc.13.146

• carboxylic acids, 3-phenylpropionic acid (1d) gave a slightly decreased amount of 3da in 54% yield (Table 1, entry 4), whereas the more sterically demanding 1e gave the desired product 3ea in a good yield (Table 1, entry 5). The reaction was carried out with different amino acids, resulting in a varied

• the desired 5-(triazinyloxy)oxazole 3aa in 78% yield (Table 1, entry 1). A series of carboxylic acids were subjected to the reaction conditions. Aromatic carboxylic acids with both electron-withdrawing and electron-donating groups gave good yields (Table 1, entries 2 and 3). In the case of aliphatic

Diastereoselective anodic hetero- and homo-coupling of menthol-, 8-methylmenthol- and 8-phenylmenthol-2-alkylmalonates

• Matthias C. Letzel,
• Hans J. Schäfer and
• Roland Fröhlich

Beilstein J. Org. Chem. 2017, 13, 33–42, doi:10.3762/bjoc.13.5

• purity (Scheme 1). Anodic hetero-coupling of carboxylates Carboxylates of aliphatic carboxylic acids are oxidized to carbonyloxy radicals at a platinum electrode at potentials being generally higher than 2.0 V (vs NHE). The carbonyloxy radicals undergo fast decarboxylation to alkyl radicals at or near

Synthesis of α,β-unsaturated esters via a chemo-enzymatic chain elongation approach by combining carboxylic acid reduction and Wittig reaction

• Yitao Duan,
• Peiyuan Yao,
• Yuncheng Du,
• Jinhui Feng,
• Qiaqing Wu and
• Dunming Zhu

Beilstein J. Org. Chem. 2015, 11, 2245–2251, doi:10.3762/bjoc.11.243

• aromatic and aliphatic carboxylic acids, including ibuprofen. The Mycobacterium CAR catalyzed carboxylic acid reduction to give aldehydes, followed by a Wittig reaction to afford the products α,β-unsaturated esters with extension of two carbon atoms, demonstrating a new chemo-enzymatic method for the

• purified enzyme. The results in Table 2 showed that a series of aromatic and aliphatic carboxylic acids were reduced to their corresponding aldehydes. For the aliphatic acids, the reduction of nonanoic acid (3a) and lauric acid (4a) resulted in higher yields than those of hexanoic acid (5a) and

Molecular-oxygen-promoted Cu-catalyzed oxidative direct amidation of nonactivated carboxylic acids with azoles

• Wen Ding,
• Shaoyu Mai and
• Qiuling Song

Beilstein J. Org. Chem. 2015, 11, 2158–2165, doi:10.3762/bjoc.11.233

• surveyed different carboxylic acids. To our delight, both aromatic and aliphatic carboxylic acids were competent candidates in this transformation (Scheme 2). For aromatic carboxylic acids, various substituents on the aromatic ring were tolerable under the standard conditions, which suggests that the

• conditions, providing the desired products 20 and 21 in 59% and 88% yield, respectively. Additionally, heterocyclic acids, such as thiophene- and furan-3-carboxylic acid were well tolerated, providing the amides 22 and 23 in acceptable yields. Gratifyingly, aliphatic carboxylic acids, such as

Preparative semiconductor photoredox catalysis: An emerging theme in organic synthesis

• David W. Manley and
• John C. Walton

Beilstein J. Org. Chem. 2015, 11, 1570–1582, doi:10.3762/bjoc.11.173

• demonstrated. P25 promoted UVA photolyses of aliphatic carboxylic acids RCO2H with electron-deficient alkenes (Z) in dry CH3CN under anaerobic conditions led to the formation of adducts RZH incorporating the carboxylic acid moiety R and an additional H atom [53][54]. Yields were low for n-alkyl radicals, but a

Synthesis of antibacterial 1,3-diyne-linked peptoids from an Ugi-4CR/Glaser coupling approach

• Martin C. N. Brauer,
• Ricardo A. W. Neves Filho,
• Bernhard Westermann,
• Ramona Heinke and
• Ludger A. Wessjohann

Beilstein J. Org. Chem. 2015, 11, 25–30, doi:10.3762/bjoc.11.4

• aliphatic carboxylic acids and aldehydes have been successfully employed in both multicomponent and coupling reactions. When performing the reaction with methyl isocyanoacetate (Table 1, entry 2) the desired products could be obtained in good yields with the ester group remaining untouched. It is important

Isocyanide-based multicomponent reactions towards cyclic constrained peptidomimetics

• Gijs Koopmanschap,
• Eelco Ruijter and
• Romano V.A. Orru

Beilstein J. Org. Chem. 2014, 10, 544–598, doi:10.3762/bjoc.10.50

A practical two-step procedure for the preparation of enantiopure pyridines: Multicomponent reactions of alkoxyallenes, nitriles and carboxylic acids followed by a cyclocondensation reaction

• Christian Eidamshaus,
• Roopender Kumar,
• Mrinal K. Bera and
• Hans-Ulrich Reissig

Beilstein J. Org. Chem. 2011, 7, 962–975, doi:10.3762/bjoc.7.108

• limitations Following the protocol mentioned before, we successfully prepared a series of 4-hydroxypyridines with chiral functional groups present in a side chain. As can be seen in Table 1 not merely chiral aliphatic carboxylic acids and nitriles such as 17 and 31 can be transformed into 4-hydroxypyridines

Transition- metal/Lewis acid free synthesis of acyl benzothiophenes via C-C bond forming reaction

• Sarbani Pal,
• Mohammad Ashrafuddin Khan,
• P. Bindu and
• P. K. Dubey

Beilstein J. Org. Chem. 2007, 3, No. 35, doi:10.1186/1860-5397-3-35

• acylation has been reported as a useful alternative to the Friedel-Crafts acylation process and a variety of aromatic and aliphatic carboxylic acids have been employed successfully. Encouraged by these results, we decided to adopt a similar strategy for the acylation of benzothiophene. We anticipated that a