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

• irradiation to harness the reactivity of alcohols and acids both upon derivatization and through direct use. By exploring recent advancements in deoxygenation reactions and the design of potential reactants, we aim to give an overview of the diverse strategies that highlight the unique reaction design and

Synthesis of 1,2,3-triazoles containing an allomaltol moiety from substituted pyrano[2,3-d]isoxazolones via base-promoted Boulton–Katritzky rearrangement

• Constantine V. Milyutin,
• Andrey N. Komogortsev and
• Boris V. Lichitsky

Beilstein J. Org. Chem. 2024, 20, 1334–1340, doi:10.3762/bjoc.20.117

• cyclization with participation of hydrazine and carbonyl functions leads to pyrazolylisoxazole D. Finally, condensation with second equivalent of hydrazine results in the target hydrazone 6. The synthetic utility of obtained 1,2,3-triazoles is demonstrated by its further derivatization. So, alkylation by MeI

(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

• development of these important bioisosteres. We will highlight both the synthetic routes used to access the proposed bioisosteric scaffolds, as well as any subsequent derivatization thereof which help expand their utility. Our aim is to provide an overview of the types of scaffold that can be prepared with

• fluxapyroxad from amine (±)-63, which was itself accessed via Curtius rearrangement of the corresponding 1,5-BCH (Scheme 5C) [42]. In 2023, Yoo and co-workers reported the synthesis of 1,5-BCHs by derivatization of 5-oxo-BCHs (±)-67 (Scheme 5D) [43]. They accessed the 5-oxo-BCHs by Simmons–Smith

• equivalent. Synthesis of 1,4-BCHs 100a–f via intramolecular [2 + 2] cycloaddition of hexa-1,5-dienes was reported by Rigotti and Bach (Scheme 11A) [55]. These reactions require the presence of one styrenyl motif for efficient excitation. Derivatization of some of the compounds formed led to further useful

Confirmation of the stereochemistry of spiroviolene

• Yao Kong,
• Yuanning Liu,
• Kaibiao Wang,
• Tao Wang,
• Chen Wang,
• Ben Ai,
• Hongli Jia,
• Guohui Pan,
• Min Yin and
• Zhengren Xu

Beilstein J. Org. Chem. 2024, 20, 852–858, doi:10.3762/bjoc.20.77

• hydroxy group, or a keto group) for further derivatization. Spiroviolene was not transformed when subjected to conditions for allylic oxidation (SeO2) even at elevated temperature [27], and the starting material was fully recovered. We have also tried hydroboration/oxidation conditions for transforming

• process. Derivatization of spiroviolene for X-ray crystallography. A) Hydroboration/oxidation reaction of spiroviolene involving a borane migration process. B) Synthesis of the hydrazone derivative of spiroviolene for single-crystal X-ray diffraction. Supporting Information Supporting Information File 19

New variochelins from soil-isolated Variovorax sp. H002

• Jabal Rahmat Haedar,
• Aya Yoshimura and
• Toshiyuki Wakimoto

Beilstein J. Org. Chem. 2024, 20, 692–700, doi:10.3762/bjoc.20.63

• this study, we isolated three new congeners of variochelin-type siderophores, variochelins C–E (3–5), along with two known compounds, variochelins A (1) and B (2), from Variovorax sp. Their structures were elucidated by a combination of NMR, ESIMS/MS, and chemical derivatization. The analysis of the

Enhanced reactivity of Li⁺@C₆₀ toward thermal [2 + 2] cycloaddition by encapsulated Li⁺ Lewis acid

• Hiroshi Ueno,
• Yu Yamazaki,
• Hiroshi Okada,
• Fuminori Misaizu,
• Ken Kokubo and
• Hidehiro Sakurai

Beilstein J. Org. Chem. 2024, 20, 653–660, doi:10.3762/bjoc.20.58

• derivatization of this novel material. In this study, we report the synthesis of Li+@C60 derivatives via the thermal [2 + 2] cycloaddition reaction of styrene derivatives, achieving significantly higher yields of monofunctionalized Li+@C60 compared to previously reported reactions. Furthermore, by combining

• accelerated 1,3-dipolar and Diels–Alder reactions [12][13], it is noteworthy that the anticipated diverse properties resulting from the derivatization of Li+@C60 have not yet been fully realized. To further leverage the unique properties of the novel ion-endohedral fullerene, achieving diverse property tuning

• thermal [2 + 2] reactions are generally simple and scalable, the reactions are scarcely applied for the derivatization of fullerenes due to the limitation in the variety of possible substrates. Considering the electronic effect of the encapsulated Li+ on the outer C60 cage, Li+@C60 can react with a wider

Switchable molecular tweezers: design and applications

• Pablo Msellem,
• Maksym Dekthiarenko,
• Nihal Hadj Seyd and
• Guillaume Vives

Beilstein J. Org. Chem. 2024, 20, 504–539, doi:10.3762/bjoc.20.45

• an achiral diamine (1,12-diaminododecane or DAD) that binds to both Zn–porphyrins and sets them further apart, a higher CD signal intensity is obtained making it a sensitive probe for determining the absolute stereochemistry of chiral carboxylates directly, without the need for derivatization. More

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

• tolerated, affording the desired products in excellent yields (92‒99%). These results indicated that the electronic effect of substituents affected the reaction only slightly. Products with substituents with derivatization feasibilities such as halogen (3ga–ia), acetyloxy (3ja), and ester groups (3ka) also

Biphenylene-containing polycyclic conjugated compounds

• Cagatay Dengiz

Beilstein J. Org. Chem. 2023, 19, 1895–1911, doi:10.3762/bjoc.19.141

• reactions involving 1,4-dibromo-2,5-dichlorobenzene (31) and substituted oxanorbornenes (26 and 30b,c), products 32a–c, with R groups representing (a) H, (b) F, and (c) –OCH2O–, were successfully synthesized, albeit with moderate yields (Scheme 7). Following that, compounds 32a–c underwent derivatization

• through Sonogashira cross-coupling reactions with alkynes featuring different protecting groups such as TIPS, TES, and TIBS. Scheme 7 illustrates the derivatization process using one of the chosen examples, specifically the TIPS group. Accordingly, the cross-coupling products 33a–c were obtained in yields

Anion–π catalysis on carbon allotropes

• M. Ángeles Gutiérrez López,
• Mei-Ling Tan,
• Giacomo Renno,
• Augustina Jozeliūnaitė,
• J. Jonathan Nué-Martinez,
• Javier Lopez-Andarias,
• Naomi Sakai and
• Stefan Matile

Beilstein J. Org. Chem. 2023, 19, 1881–1894, doi:10.3762/bjoc.19.140

• to C60 fullerenes [12]. These amines function as bases, their position next to the aromatic surface is essential to turn on anion–π interactions as soon as substrate 4 is deprotonated. Fullerene derivatization with the Bingel reaction installs a cyclopropane that continues with one or two acid

Controlling the reactivity of La@C₈₂ by reduction: reaction of the La@C₈₂ anion with alkyl halide with high regioselectivity

• Yutaka Maeda,
• Saeka Akita,
• Mitsuaki Suzuki,
• Michio Yamada,
• Takeshi Akasaka,
• Kaoru Kobayashi and
• Shigeru Nagase

Beilstein J. Org. Chem. 2023, 19, 1858–1866, doi:10.3762/bjoc.19.138

• , the third carbon allotrope, have unique spherical molecular structures and exhibit high reactivity as electron-deficient polyolefins. The excellent redox properties of fullerenes are useful for their chemical derivatization and practical applications [1][2][3][4][5]. Fullerene anions can be easily

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

• electrospray ionization HRESIMS analysis, and quantum chemical electronic CD calculations. Furthermore, the absolute configurations of sugar residues were determined by derivatization of the hydrolysates with ʟ-cysteine methyl ester and o-tolyl isothiocyanate followed by HPLC analysis. The anti-inflammatory

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

• and electron-poor arenes 57, including hindered ortho-substituted derivatives (Scheme 12). Further derivatization of the spirocyclic motif led to SPIAd-derived iodonium ylides 58, whose radiofluorinations showed improved radiochemical conversions with a variety of arene derivatives (Scheme 13) [16

The effect of dark states on the intersystem crossing and thermally activated delayed fluorescence of naphthalimide-phenothiazine dyads

• Liyuan Cao,
• Xi Liu,
• Xue Zhang,
• Jianzhang Zhao,
• Fabiao Yu and
• Yan Wan

Beilstein J. Org. Chem. 2023, 19, 1028–1046, doi:10.3762/bjoc.19.79

• state energy), while keeping other factors intact to a large extent (e.g., the LE state energy). This is an important advantage for the study of complicated photophysical mechanisms involved in TADF processes. The syntheses of the dyads are based on the known derivatization chemistry of NI and PTZ

• the delayed fluorescence, via the rISC process. In addition, the lifetime of the long-lived component of the compound under air atmosphere is greatly shortened, which also verifies that these compounds have TADF properties. Moreover, with our derivatization approach, the geometry and electron-donating

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

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 transesterification. The method was also applied in the derivatization of a steroid derivative 95, affording the corresponding product 96 (Scheme 19) [42]. The reactions are [6 + 1] and [7 + 1] annulations for cyclohex-2-enone and cyclohept-2-enone, respectively. The treatment of (M)-2'-methyl

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

• (Scheme 7) [51]. Without this derivatization procedure, we could not accurately detect compound 3aa by HPLC–UV, since the chromatographic signals of untreated compound 3aa were broad and blurry. Next, the reactant scope of the reaction was explored by involving to the reaction APBTTs 1a–h, bearing various

• reaction in 1-(2-bromophenyl)-5-(butylsulfanyl)pyrrolidin-2-one. Approach to PBTAs via intramolecular cyclizations of 1-(2-thiophenyl)pyrroles. A new approach to PBTAs via nucleophile-induced ring contraction in pyrrolo[2,1-c][1,4]benzothiazines. Reaction of APBTT 1a with methanol (2a). Derivatization of

• . Transformations of compounds 5 in solutions. Reaction of APBTT 1a with benzylamine. Derivatization of PBTA 7a. Reaction of APBTTs 1a–h and benzylamine. Isolated yields are given; reaction scale: a mixture of 1 (0.45 mmol), benzylamine (0.49 mmol, 54 µL) and anhydrous toluene (3 mL) was stirred in an oven-dried

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

• formylation products. The methodology was later exploited in the expedient synthesis of the Taxol core (Scheme 34) [71]. Tandem conjugate borylations and silylations Chiral organoboron compounds are well-known synthetic building blocks with diverse possibilities for subsequent derivatization (e.g., oxidation

• cascade borylation/Michael addition sequence leading to enantioenriched spiroindane boronates 174 (Scheme 44A) [85]. The reaction showed good functional group tolerance. Further derivatization, as well as scale-up (1 mmol) of the reaction were successfully performed (72% yield, 89% ee, dr >20:1). Based on

• derivatization is possible through the oxidation of the silyl motif to alcohol or the dehydration of the aldol adduct. Other tandem conjugate addition/enolate-trapping reactions In 2016, Nishiyama and co-workers have studied a three-component coupling reaction of alkynes, enones, and aldehydes via direct

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

Discrimination of β-cyclodextrin/hazelnut (Corylus avellana L.) oil/flavonoid glycoside and flavonolignan ternary complexes by Fourier-transform infrared spectroscopy coupled with principal component analysis

• Nicoleta G. Hădărugă,
• Gabriela Popescu,
• Dina Gligor (Pane),
• Cristina L. Mitroi,
• Sorin M. Stanciu and
• Daniel Ioan Hădărugă

Beilstein J. Org. Chem. 2023, 19, 380–398, doi:10.3762/bjoc.19.30

• flavonolignans as impurities) and were purchased from Sigma-Aldrich, St. Louis, MO, USA. Ethanol used for complex synthesis was of 96% concentration (v/v) and was purchased from ChimReactiv (Bucharest, Romania). The analysis of the FA profile of the hazelnut oil required the derivatization (transesterification

• ) of the FA glycerides to the corresponding FA methyl esters (FAMEs) [11][13]. The derivatization involved methanol–boron trifluoride (20% BF3), hexane (GC grade) and anhydrous sodium sulfate, all purchased from Merck & Co., Inc., Rahway, NJ, USA. Sodium chloride (reagent grade) used for the separation

• Sigma-Aldrich, St. Louis, MO, USA). Finally, 2-propanol (ACS reagent, Reag. Ph. Eur.) used for FTIR cleaning was obtained from Merck & Co., Inc., Rahway, NJ, USA. Gas chromatography–mass spectrometry (GC–MS) The FA profile of the hazelnut oil was determined by GC–MS, after derivatization to FAMEs

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 122 for further derivatization and structure–activity relationship (SAR) studies [59]. In this case, an intramolecular NHK was carried out on compound 120 prepared from 3-allylcyclopent-2-enone (119) to give the tricyclic compound 121 possessing the eight-membered ring in 73% yield as the major

1,4-Dithianes: attractive C2-building blocks for the synthesis of complex molecular architectures

• Bram Ryckaert,
• Ellen Demeyere,
• Frederick Degroote,
• Hilde Janssens and
• Johan M. Winne

Beilstein J. Org. Chem. 2023, 19, 115–132, doi:10.3762/bjoc.19.12

• generality in this aspect. In principle, 1,4-dithianes should offer good options for the development as C2-synthons that are complementary in scope to the more widely used 1,3-dithianes, but the β-fragmentation problem (cf. Scheme 2) hampers their easy derivatization. It should be noted that this elimination

• integral part of synthetic targets, or can again serve as a handle for further derivatization. An obvious choice here is to oxidize the sulfur atoms to give (vinyl)sulfones, which can be used in a range of further bond formations, in particular Diels–Alder reactions (cf. chapter 3, Scheme 8). In this

Digyalipopeptide A, an antiparasitic cyclic peptide from the Ghanaian Bacillus sp. strain DE2B

• Adwoa P. Nartey,
• Aboagye K. Dofuor,
• Kofi B. A. Owusu,
• Anil S. Camas,
• Hai Deng,
• Marcel Jaspars and
• Kwaku Kyeremeh

Beilstein J. Org. Chem. 2022, 18, 1763–1771, doi:10.3762/bjoc.18.185

• advanced Marfey’s method [16][17][18] involving the complete hydrolysis of compound 1 followed by derivatization of the resultant amino acid residues with N-α-(2,4-dinitro-5-fluorophenyl)-ʟ-alanine amide (ʟ-FDAA). Similar derivatization reactions between ʟ-FDAA and authentic amino acid standards, followed

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

• group where an immobilized lipase (e.g., CALB) facilitated the derivatization of high-boiling benzyl alcohol in scaled Curtius rearrangement reactions. Ultimately, this approach negated the use of column chromatography in favor of a simple trituration process to isolate pure carbamate products [106

Solid-phase total synthesis and structural confirmation of antimicrobial longicatenamide A

• Takumi Matsumoto,
• Takefumi Kuranaga,
• Yuto Taniguchi,
• Weicheng Wang and
• Hideaki Kakeya

Beilstein J. Org. Chem. 2022, 18, 1560–1566, doi:10.3762/bjoc.18.166

• microbial world. To elucidate the role of compounds 1–4 in the microbial world, developing a strategy to synthesize compounds 1–4, including future derivatization to produce probe molecules, is required. Herein, we report the total synthesis of peptide 1 by Fmoc-based solid-phase peptide synthesis [9] and

• ], a solid-phase strategy can facilitate the production of a wider variety of analogous compounds than solution-phase synthesis [11]. Consequently, in this study, compound 1 was synthesized using a solid-phase strategy for future derivatization to produce probe molecules for deciphering microbial