Cryptophycin unit B analogues

• Thomas Schachtsiek,
• Jona Voss,
• Maren Hamsen,
• Beate Neumann,
• Hans-Georg Stammler and
• Norbert Sewald

Beilstein J. Org. Chem. 2025, 21, 526–532, doi:10.3762/bjoc.21.40

• macrolactamisation [21]. The syntheses of required unit A [28], C [29][30], and D [31] building blocks were accomplished as described previously. tert-Butyl-protected leucic acid 14 and Fmoc-β-aminopivalic acid (15) were connected by Steglich esterification (Scheme 2) and after cleavage of the tert-butyl ester group

• coupled to either one of the two unit A precursors 18 and 19 by Yamaguchi esterification. CDA fragments 20 and 21 were connected to unit B derivatives 11 and 13 through amidation which provided seco-cryptophycins 22 and 23 in yields of 49% and 38%, respectively. Starting from seco-cryptophycin 22

Beyond symmetric self-assembly and effective molarity: unlocking functional enzyme mimics with robust organic cages

• Keith G. Andrews

Beilstein J. Org. Chem. 2025, 21, 421–443, doi:10.3762/bjoc.21.30

• ][383][384][385], and do not require metal parameterization [140][386][387]. Catalysis: Stable, soluble organic cages finally open the possibility of organocatalysis in confined spaces: organization and polarization. Hexapyridyl cage 2 was shown to accelerate acyl transfer esterification reactions by

Advances in radical peroxidation with hydroperoxides

• Oleg V. Bityukov,
• Pavel Yu. Serdyuchenko,
• Andrey S. Kirillov,
• Gennady I. Nikishin,
• Vera A. Vil’ and
• Alexander O. Terent’ev

Beilstein J. Org. Chem. 2024, 20, 2959–3006, doi:10.3762/bjoc.20.249

The charge transport properties of dicyanomethylene-functionalised violanthrone derivatives

• Sondos A. J. Almahmoud,
• Joseph Cameron,
• Dylan Wilkinson,
• Michele Cariello,
• Claire Wilson,
• Alan A. Wiles,
• Peter J. Skabara and
• Graeme Cooke

Beilstein J. Org. Chem. 2024, 20, 2921–2930, doi:10.3762/bjoc.20.244

• properties. Due to the low solubility of violanthrone in the majority of organic solvents, special attention has been drawn to its dihydroxy derivative (Figure 1), which allows further modification to the materials via etherification or esterification [29][30]. There has been a report on the structural

Recent advances in transition-metal-free arylation reactions involving hypervalent iodine salts

• Ritu Mamgain,
• Kokila Sakthivel and
• Fateh V. Singh

Beilstein J. Org. Chem. 2024, 20, 2891–2920, doi:10.3762/bjoc.20.243

• include arylation, iodination, alkynylation, thiophenolation, amination, and esterification, were carried out. Among these reactions, esterification was achieved in moderate yield under metal-free conditions by reacting the synthesized naproxen methyl ester (2-methoxyphenyl)iodonium

• bis(4-methoxyphenyl)iodonium diacetate (70) or ArI(OH)OTs highly regioselective gemfibrozil methyl ester derived iodonium salts 71 were obtained in moderate to good yield. These salts were then used for various modifications like alkynylation, arylation, esterification, etherification, fluorination

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

• -dimethylalk-5-enoates in a homologous series from C11–C16, were characterized by GC–MS and GC–IR analysis and various microderivatization reactions including hydrogenation and esterification leading to methyl and pyridylmethyl esters. In addition, dimethyloxazoline formation helped to localize the double bond

• ]. Synthesis of pyridylmethyl esters: For esterification with 3-pyridinemethanol, freshly distilled oxalyl chloride (20 µL) was added to the gland extract (100 µL). After one day, excess oxalyl chloride and the solvent were evaporated under N2 and the sample was redissolved in DCM. For esterification

A review of recent advances in electrochemical and photoelectrochemical late-stage functionalization classified by anodic oxidation, cathodic reduction, and paired electrolysis

• Nian Li,
• Ruzal Sitdikov,
• Ajit Prabhakar Kale,
• Joost Steverlynck,
• Bo Li and
• Magnus Rueping

Beilstein J. Org. Chem. 2024, 20, 2500–2566, doi:10.3762/bjoc.20.214

Metal-free double azide addition to strained alkynes of an octadehydrodibenzo[12]annulene derivative with electron-withdrawing substituents

• Naoki Takeda,
• Shuichi Akasaka,
• Susumu Kawauchi and
• Tsuyoshi Michinobu

Beilstein J. Org. Chem. 2024, 20, 2234–2241, doi:10.3762/bjoc.20.191

• 5 was prepared from phthalimide (1, Scheme 1). Iodination followed by hydrolysis afforded 4,5-diiodophthalic acid (2) in 46.7% yield. Esterification with 1-hexanol yielded compound 3 in 56.8% yield and the subsequent Sonogashira coupling with trimethylsilylacetylene provided compound 4 in 80.0

Natural resorcylic lactones derived from alternariol

• Joachim Podlech

Beilstein J. Org. Chem. 2024, 20, 2171–2207, doi:10.3762/bjoc.20.187

Factors influencing the performance of organocatalysts immobilised on solid supports: A review

• Zsuzsanna Fehér,
• Dóra Richter,
• Gyula Dargó and
• József Kupai

Beilstein J. Org. Chem. 2024, 20, 2129–2142, doi:10.3762/bjoc.20.183

• was studied and compared in the esterification of methanol or glycerol with oleic acid (1). It was observed that substrate conversion and product yield also depended on the particle morphology. Rope-type propylsulfonic SBA-15 mesoporous silica gel showed the highest catalytic activity in both studied

• esterification reactions (Scheme 1). By adjusting the pore size of the support, the catalyst selectivity can be influenced. To counteract the decrease in selectivity caused by catalyst immobilisation, the concept of “confinement” was introduced [62], which involves forcing the catalytic moieties into confined

• , contributing to more sustainable and efficient catalytic processes. Esterification of oleic acid (1) with propylsulfonic acid (Pr-SO3H)-functionalised mesoporous silica catalyst 4. Using confinement of organocatalytic units for improving the enantioselectivity of silica-supported organocatalysts in the Michael

Negishi-coupling-enabled synthesis of α-heteroaryl-α-amino acid building blocks for DNA-encoded chemical library applications

• Matteo Gasparetto,
• Balázs Fődi and
• Gellért Sipos

Beilstein J. Org. Chem. 2024, 20, 1922–1932, doi:10.3762/bjoc.20.168

• subsequent re-esterification was necessary to achieve the desired ketoester. Reduction of the oximes Oximes are commonly reduced to the corresponding amines using either palladium on activated carbon and hydrogen gas [65][66][67][68], or with zinc and a Brønsted acid as source of hydrogen [68][69]. Both

(Bio)isosteres of ortho- and meta-substituted benzenes

• H. Erik Diepers and
• Johannes C. L. Walker

Beilstein J. Org. Chem. 2024, 20, 859–890, doi:10.3762/bjoc.20.78

• esterification of alcohol (±)-5 gave redox active ester (±)-6, which was itself shown to be a suitable substrate for nickel-catalysed decarboxylative cross coupling reactions to aryl-substituted BCPs (±)-7. Oxidation of alcohol (±)-8 gave acid (±)-9 which yielded amine (±)-10 after a Curtius rearrangement

• oxidation of alcohol 175 with Dess–Martin periodinane. Synthesis of cubane 166 was then achieved by [2 + 2] cycloaddition of enone 176 using acetone as the photosensitiser (to 177), the first Favorskii ring contraction (to 178), deketalisation, the second Favorskii ring contraction and esterification (to

Ortho-ester-substituted diaryliodonium salts enabled regioselective arylocyclization of naphthols toward 3,4-benzocoumarins

• Ke Jiang,
• Cheng Pan,
• Limin Wang,
• Hao-Yang Wang and
• Jianwei Han

Beilstein J. Org. Chem. 2024, 20, 841–851, doi:10.3762/bjoc.20.76

• diaryliodonium salts in a cascade cyclization, the cyclization features a copper-catalyzed activation strategy involving the cleavage of the C–I bond and esterification. The resulting cascade of selective arylation/intramolecular cyclization facilitated the synthesis of 3,4-benzocoumarin derivatives. The

Substrate specificity of a ketosynthase domain involved in bacillaene biosynthesis

• Zhiyong Yin and
• Jeroen S. Dickschat

Beilstein J. Org. Chem. 2024, 20, 734–740, doi:10.3762/bjoc.20.67

• ) allowed for test incubations with unlabelled glutamic acid in the presence of the cofactor pyridoxal phosphate (PLP), showing the complete conversion of glutamic acid (3) into γ-aminobutyric acid (4) (Scheme 2). The crude product was used without purification for a Schotten–Baumann esterification with

• ester 5 was coupled with the carboxylic acid (S)-8, derived from ʟ-leucine ((S)-6) via hydroxyacid (S)-7, to yield the amide (S)-9. Deprotection through catalytic hydrogenation to (S)-10, saponification of the acetate ester and Steglich esterification with N-acetylcysteamine gave access to the desired

Chemoenzymatic synthesis of macrocyclic peptides and polyketides via thioesterase-catalyzed macrocyclization

• Senze Qiao,
• Zhongyu Cheng and
• Fuzhuo Li

Beilstein J. Org. Chem. 2024, 20, 721–733, doi:10.3762/bjoc.20.66

• pikromycin and the aglycones in this family, 10-deoxymethynolide (24) and norbonolide (25), using asymmetric aldol reaction, Yamaguchi esterification, and ring-closing metathesis as key steps [65][66]. Nevertheless, the inherent complexity of these natural products demands high step counts, leading to low

Copper-catalyzed multicomponent reaction of β-trifluoromethyl β-diazo esters enabling the synthesis of β-trifluoromethyl N,N-diacyl-β-amino esters

• Youlong Du,
• Haibo Mei,
• Ata Makarem,
• Ramin Javahershenas,
• Vadim A. Soloshonok and
• Jianlin Han

Beilstein J. Org. Chem. 2024, 20, 212–219, doi:10.3762/bjoc.20.21

• IKERBASQUE, Basque Foundation for Science, Alameda Urquijo 36-5, Plaza Bizkaia, 48011 Bilbao, Spain 10.3762/bjoc.20.21 Abstract An efficient multicomponent reaction of newly designed β-trifluoromethyl β-diazo esters, acetonitrile, and carboxylic acids via an interrupted esterification process under copper

• . Conclusion In summary, a series of new β-trifluoromethyl β-diazo esters have been designed, which are applied for the first time in a cascade reaction through an interrupted esterification with nitrile ylides as the key intermediates under copper-catalysis conditions. Varieties of unsymmetric trifluoromethyl

Sulfur-containing spiroketals from Breynia disticha and evaluations of their anti-inflammatory effect

• Ken-ichi Nakashima,
• Naohito Abe,
• Masayoshi Oyama,
• Hiroko Murata and
• Makoto Inoue

Beilstein J. Org. Chem. 2023, 19, 1604–1614, doi:10.3762/bjoc.19.117

• 5.78 (d, J = 7.8 Hz, 1H, H-1′); δC 94.0 (C-1′)] implied that compound 4 was a β-glycosyl ester. The HMBC correlation of H-1′ with a carbonyl carbon [δC 174.7 (C-3)] revealed that esterification occurred at C-3 with a glucopyranose moiety at the anomeric position (Figure 4). A β-1,3-glucosyl linkage

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

• -enyl) lipid chain (Figure 9) [88]. The synthesis starts from serine 9.1 and produce (R)-solketal (9.2) following a three-step protocol [89] that was recently revisited [90] (diazotation, esterification, acetalization). Then, the incorporation of the oleyl chain (C18H35) was achieved by the

• Markowska et al. in 1993 [134]. As detailed in Figure 28, the synthesis starts with a Mitsunobu esterification of 28.1 with thioacetic acid to produce the thioester 28.2. Then, the reduction with lithium aluminium hydride produced the thiol 28.3. Finally, the phosphocholine moiety was introduced by using

Two new lanostanoid glycosides isolated from a Kenyan polypore Fomitopsis carnea

• Winnie Chemutai Sum,
• Sherif S. Ebada,
• Didsanutda Gonkhom,
• Cony Decock,
• Rémy Bertrand Teponno,
• Josphat Clement Matasyoh and
• Marc Stadler

Beilstein J. Org. Chem. 2023, 19, 1161–1169, doi:10.3762/bjoc.19.84

• was shown to be a key player in lanostane triterpenoid cytotoxicity; increased activity was demonstrated either by its esterification with glucose or by its reduction into a hydroxymethylene group unlike its presence as a free carboxylic acid moiety [23]. Thus, our findings provide further insights

Intermediates and shunt products of massiliachelin biosynthesis in Massilia sp. NR 4-1

• Till Steinmetz,
• Blaise Kimbadi Lombe and
• Markus Nett

Beilstein J. Org. Chem. 2023, 19, 909–917, doi:10.3762/bjoc.19.69

• reactions (e.g., hydrolysis, esterification, oxidation) might be due to the isolation conditions or they could be attributed to unspecific enzymatic biotransformations. For compound 1, no spontaneous conversion to the ester 2 was observed, even after storage in methanol for two months. In contrast, the

Synthesis of medium and large phostams, phostones, and phostines

• Jiaxi Xu

Beilstein J. Org. Chem. 2023, 19, 687–699, doi:10.3762/bjoc.19.50

• intramolecular esterification gave the cyclized products 74 and 75 in 82% yield with a 5:1 ratio of anti/cis diastereomers accompanied by a dimeric byproduct 76 in 2.5% yield. The anti-diastereomer with cis-PhO and Me groups as major product 74 is attributed to the stereoelectronic effect between the n-orbital

Combretastatins D series and analogues: from isolation, synthetic challenges and biological activities

• Jorge de Lima Neto and
• Paulo Henrique Menezes

Beilstein J. Org. Chem. 2023, 19, 399–427, doi:10.3762/bjoc.19.31

• , the authors employed an Ullmann-type condensation [28] between ester 14 and 4-iodobenzaldehyde (15) to give the corresponding diaryl ether 16 in 78% yield. The subsequent demethylation reaction using boron triiodide also promoted the hydrolysis of the ester, and thus a re-esterification step was

• esterification reactions gave the ester 33 which was submitted to a Sonogashira coupling reaction with propargyl alcohol to give the advanced intermediate 34 [34]. Partial hydrogenation of the triple bond in 34 using Lindlar’s catalyst led to the cis-allylic alcohol 35 and subsequent ester hydrolysis led to the

• protection with BnBr and oxidation led to the carboxylic acid 107. Esterification of the carboxylic acid followed by the cleavage of the silyl ether using TBAF and hydrolysis led to the seco-acid 108. Macrolactonization using the Mitsunobu conditions gave combretastatin D-4 (4) after cleavage of the benzyl

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

• H10Bpin with the borinic ester intermediate 44 showed no scrambling of the 10B label, suggesting a σ-bond metathesis mechanism for this transborylation reaction (Scheme 10). Thomas et al. reported the H-B-9-BBN-catalysed esterification of alkyl fluorides, using carboxylic acids and HBpin (Scheme 11) [75

• -catalysed asymmetric reduction of propargylic ketones and the proposed mechanism. H-B-9-BBN-catalysed C–F esterification of alkyl fluorides and the proposed mechanism. H-B-9-BBN-catalysed 1,4-hydroboration of enones and the proposed mechanism. Boric acid-promoted reduction of esters, lactones, and

Strategies to access the [5-8] bicyclic core encountered in the sesquiterpene, diterpene and sesterterpene series

• Cécile Alleman,
• Charlène Gadais,
• Laurent Legentil and
• François-Hugues Porée

Beilstein J. Org. Chem. 2023, 19, 245–281, doi:10.3762/bjoc.19.23

• compound. The diastereoselectivity was modest with a dr of 3:2. Esterification of the secondary alcohol followed by silyl removal gave access to the key scaffold 122 (Scheme 22). 2.2 Synthesis of aquatolide (4): Late-stage NHK medium-ring formation Aquatolide (4) is a sesquiterpene lactone isolated from

Nostochopcerol, a new antibacterial monoacylglycerol from the edible cyanobacterium Nostochopsis lobatus

• Naoya Oku,
• Saki Hayashi,
• Yuji Yamaguchi,
• Hiroyuki Takenaka and
• Yasuhiro Igarashi

Beilstein J. Org. Chem. 2023, 19, 133–138, doi:10.3762/bjoc.19.13

• esterification. The resulting ester 2a or 2b was purified by reversed-phase HPLC and deprotected by a short treatment with 80% aqueous acetic acid at 58–59 °C to give 1-linoleoyl-sn-glycerol (3a) or 3-linoleoyl-sn-glycerol (3b), respectively (Scheme 1). Similarly, to our experience during the isolation of