Natural resorcylic lactones derived from alternariol

• Joachim Podlech

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

Multicomponent syntheses of pyrazoles via (3 + 2)-cyclocondensation and (3 + 2)-cycloaddition key steps

• Ignaz Betcke,
• Alissa C. Götzinger,
• Maryna M. Kornet and
• Thomas J. J. Müller

Beilstein J. Org. Chem. 2024, 20, 2024–2077, doi:10.3762/bjoc.20.178

• oxalate (9) and alkylphenones 10 through a sterically hindered Claisen condensation, producing a six-membered lithium enolate salt. Subsequent cyclocondensation with hydrazines concludes the formation of pyrazoles. However, this process could not be performed as a one-pot synthesis, as the solvent had to

• from di-tert-butyldiazocarboxylate (23), aryl-substituted di-Boc-hydrazines 26 were prepared by the addition of aryllithium species generated in situ by lithium-halogen exchange of aryl halides [55]. Gerstenberger et al. used this entry for the one-pot synthesis of N-arylpyrazoles 25, as depicted in

• pyrazole 88 (Scheme 31) [114]. In addition to pyrazoles, functionalized pyrimidines can also be prepared in a one-pot process using this method. In 2001, Bouillon et al. reported a one-pot process for synthesizing fluorinated pyrazoles. Initially, a lithium–halogen exchange was carried out on fluorinated

Harnessing the versatility of hydrazones through electrosynthetic oxidative transformations

• Aurélie Claraz

Beilstein J. Org. Chem. 2024, 20, 1988–2004, doi:10.3762/bjoc.20.175

• thiocyanation of ketene dithioacetals, Wang and Yang et al. mentioned one example of thiocyanation of benzaldehyde-derived hydrazone 120 using potassium thiocyanate as a source of thiocyanate radical. The electrolysis was conducted in the presence of two equivalents of water in acetonitrile with lithium

• reaction conditions. For instance, the use of lithium perchlorate as supporting electrolyte in acetonitrile at room temperature in a divided cell equipped with two platinum electrodes led exclusively to diazines 131 in good yields. In contrast, when the electrolysis was conducted in methanol containing

• yield the unsubstituted hydrazone 146. Dropwise addition of this solution during the electrolysis to the anodic chamber containing the olefin 147, lithium perchlorate and the photocatalyst in acetonitrile delivered the desired olefin product 148. From a mechanistic point of view, the

1,2-Difluoroethylene (HFO-1132): synthesis and chemistry

• Liubov V. Sokolenko,
• Taras M. Sokolenko and
• Yurii L. Yagupolskii

Beilstein J. Org. Chem. 2024, 20, 1955–1966, doi:10.3762/bjoc.20.171

• -difluoroethylene was based on 1,2-dichloro-1,2-difluoroethane (HCFC-132) [48][49][50][51][52], prepared from 1,1,2,2-tetrachloro-1,2-difluoroethane (CFC-112) by reduction using lithium aluminum hydride [48][49][50][51] or photoreduction (Scheme 2) [51]. The resulting HCFC-132 reacted with zinc [47][49][52] or

Electrochemical radical cation aza-Wacker cyclizations

• Sota Adachi and
• Yohei Okada

Beilstein J. Org. Chem. 2024, 20, 1900–1905, doi:10.3762/bjoc.20.165

• condition gave better results (Table 1, entry 6). Previously, we reported that lithium perchlorate (LiClO4)/nitromethane (CH3NO2) solution was an effective medium to facilitate radical cation reactions [21][22][23][24][25]. However, interestingly, it was not productive for the electrochemical aza-Wacker

A facile three-component route to powerful 5-aryldeazaalloxazine photocatalysts

• Ivana Weisheitelová,
• Radek Cibulka,
• Marek Sikorski and
• Tetiana Pavlovska

Beilstein J. Org. Chem. 2024, 20, 1831–1838, doi:10.3762/bjoc.20.161

• -deazaflavins [11][12][13]. Recently, it has been discovered that both 5-deazaflavins 1 and 5-deazaalloxazines 2, which have an aryl substituent in position C(5), form stable radicals that act as powerful reductive photocatalysts with a reducing power comparable to that of lithium [E*(1/1•) = −3.3 V vs SCE

Syntheses and medicinal chemistry of spiro heterocyclic steroids

• Laura L. Romero-Hernández,
• Ana Isabel Ahuja-Casarín,
• Penélope Merino-Montiel,
• Sara Montiel-Smith,
• José Luis Vega-Báez and
• Jesús Sandoval-Ramírez

Beilstein J. Org. Chem. 2024, 20, 1713–1745, doi:10.3762/bjoc.20.152

• steroidal 17-ketones were first alkylated in the presence of the lithium derivative of ethyl propiolate. After stereoselective formation of the corresponding adduct, the triple bond was chemoselectively reduced under catalytic hydrogenation using 5% palladium on charcoal. As a final step, a p

Benzylic C(sp³)–H fluorination

• Alexander P. Atkins,
• Alice C. Dean and
• Alastair J. J. Lennox

Beilstein J. Org. Chem. 2024, 20, 1527–1547, doi:10.3762/bjoc.20.137

• for the heterobenzylic position, as shown by compound 4. In 2018, a subsequent publication by the same group detailed the use of increased lithium carbonate and NFSI loadings (conditions [B]) to access the difluorinated products [37]. This report also demonstrated a single example of 18F

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

• ; lithium salt activation; olefin oxyamination; oxazoline; Introduction Hypervalent iodine(III) reagents, also known as λ3–iodanes, have been well established and used in organic synthesis for the past decades [1][2][3][4][5]. The pioneering works of Fuchigami and Fugita, Ochiai, Kita, and later the

• 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

(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

• synthesis of some 1,5-BCHeps, including 134b, was also possible on mmol scale. Through derivatization of iodine-substituted 1,5-BCHeps 134f and 134g, an even larger number of 1,5-BCHeps were accessed (Scheme 14B) [27][47]. For example, lithium–halogen exchange was used to prepare acids 135f–g and boronic

• ]. A wide variety of 1,2,3-BCPs bearing substituents in the bridge position were reported by Measom and co-workers in their study on the lithium–halogen exchange of 2-bromo-1,2,3-BCPs [78]. Larger bridged bicyclic structures such as bicyclo[2.1.1]hexane offer multiple different exit vectors for

SOMOphilic alkyne vs radical-polar crossover approaches: The full story of the azido-alkynylation of alkenes

• Julien Borrel and
• Jerome Waser

Beilstein J. Org. Chem. 2024, 20, 701–713, doi:10.3762/bjoc.20.64

• presence of transition metal catalysts [11][12][13][14]. Currently, this motif is synthesized by sequential introduction of the two functional groups [11][12][13]. Addition of a lithium acetylide to an epoxide affords the corresponding homopropargylic alcohol which can then undergo a sequence of mesylation

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

• , Graduate School of Science, Tohoku University, 6-3 Aoba, Aramaki, Aoba-ku, Sendai 980-8578, Japan Division of Applied Chemistry, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan 10.3762/bjoc.20.58 Abstract Lithium ion-endohedral fullerene (Li+@C60), a member of

• progress in synthetic procedures has contributed to diversifying their properties, enabling widespread and interdisciplinary applications in various research fields, such as biomedicine, photovoltaic devices, and materials chemistry. Meanwhile, lithium ion-endohedral fullerenes (Li+@C60) [8], the first

Synthesis of 2,2-difluoro-1,3-diketone and 2,2-difluoro-1,3-ketoester derivatives using fluorine gas

• Alexander S. Hampton,
• David R. W. Hodgson,
• Graham McDougald,
• Linhua Wang and
• Graham Sandford

Beilstein J. Org. Chem. 2024, 20, 460–469, doi:10.3762/bjoc.20.41

• lithium hexamethyldisilazane following a literature procedure reported by Liu and co-workers (see Supporting Information File 1) [44]. Subsequently, difluorinations of DBM substrates 1b–n were performed under conditions similar to those optimized for the preparation of 3a. The desired difluorinated

(E,Z)-1,1,1,4,4,4-Hexafluorobut-2-enes: hydrofluoroolefins halogenation/dehydrohalogenation cascade to reach new fluorinated allene

• Nataliia V. Kirij,
• Andrey A. Filatov,
• Yurii L. Yagupolskii,
• Sheng Peng and
• Lee Sprague

Beilstein J. Org. Chem. 2024, 20, 452–459, doi:10.3762/bjoc.20.40

• the corresponding =CF2 containing products [10]. In addition to complexes of aluminum and boron, several magnesium and lithium silyl reagents were prepared and proved to be good nucleophiles in reactions with (Z)-1,1,1,4,4,4-hexafluorobut-2-ene, as a result of which the corresponding

• important synthons, which are widely used in agrochemicals, pharmaceuticals and other fields [24][25][26]. Fluoroorganic lithium and Grignard reagents have been obtained by the metalation reactions of organofluorine compounds containing bromine and iodine atoms with alkyllithium and Grignard reagents

• . Although olefin 3 has been available for many decades, only one paper describes its lithiation with methyllithium and the subsequent reaction of the lithium compound with trifluoroacetophenone [27]. We began our research on the reactivity of the bromobutenes 3a,b with isopropylmagnesium chloride (iPrMgCl

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

• ] (Scheme 11A). This transformation occurred under light irradiation either in the presence or absence of a RuII photoredox catalyst. It was found that the chiral lithium phosphate catalyst (R)-TRIP-Li played a crucial role in accelerating the reaction rate. Following an in-depth analysis of the mechanism

• substitution with alcohol 94 in the presence of lithium phthalimide 95 leads to product 96 and turns over the catalytic cycle. Importantly, species 93 can be detected by high resolution mass spectrometry, when the reaction is carried out without nucleophile and using stoichiometric amounts of PTH1. H. Fu and

Aldiminium and 1,2,3-triazolium dithiocarboxylate zwitterions derived from cyclic (alkyl)(amino) and mesoionic carbenes

• Nedra Touj,
• François Mazars,
• Guillermo Zaragoza and
• Lionel Delaude

Beilstein J. Org. Chem. 2023, 19, 1947–1956, doi:10.3762/bjoc.19.145

• (−)-menthone was obtained in a separate step by deprotonating the corresponding aldiminium triflate with lithium diisopropylamide (LDA) at −78 °C [8]. Herein, we disclose the synthesis of three CAAC·CS2 and six MIC·CS2 inner salts from the corresponding aldiminium or 1,2,3-triazolium salts and carbon disulfide

Biphenylene-containing polycyclic conjugated compounds

• Cagatay Dengiz

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

• subjecting α,α,α′,α′-tetrabromo-o-xylene (16) to t-BuOK to anhydrous conditions, biphenylene derivative 17 was obtained with a yield of 69% (Scheme 3). In the final step of the synthesis, a halogen–lithium exchange was carried out, followed by treatment with MeOH, resulting in a 79% yield of benzo[b

• , resulting in the formation of compound 75. Further transformation through lithium–halogen exchange, followed by reaction with Me3SiCl, yielded bis(trimethylsilylated) intermediate 76 in a 90% yield. By utilizing the conditions outlined in the prior investigation [49], compound 76 was subjected to a reaction

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

• electrophile compared to other alkyl halides, such as related bromides and chlorides. As a result, an effective iododecarboxylation provides a versatile platform for a range of decarboxylative reactions. Shang and co-workers recently found that aliphatic carboxylates and lithium iodide could undergo

A deep-red fluorophore based on naphthothiadiazole as emitter with hybridized local and charge transfer and ambipolar transporting properties for electroluminescent devices

• Suangsiri Arunlimsawat,
• Patteera Funchien,
• Pongsakorn Chasing,
• Atthapon Saenubol,
• Taweesak Sudyoadsuk and
• Vinich Promarak

Beilstein J. Org. Chem. 2023, 19, 1664–1676, doi:10.3762/bjoc.19.122

• increasing voltage (CELIV) or MIS-CELIV technique [59][60][61]. Electron- and hole-only MIS devices were fabricated with the structures of indium tin oxide (ITO)/magnesium fluoride (MgF2) (20 nm)/TPECNz (100 nm)/lithium fluoride (LiF) (1 nm)/aluminum (Al) (100 nm) and ITO/MgF2 (20 nm)/TPECNz (100 nm

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

• –Cu(I) complexes 12 (Scheme 5). A variety of bases, namely metal alkoxides, alkali metal carbonates, n-butyllithium, and lithium bis(trimethylsilyl)amide have been employed for this purpose. In 2010, Diez-González et al. synthesized a variety of NHC–Cu(I) complexes 14 from imidazolium salts 13 using

• diaminocarbenes) Cu(I) hexamethyldisilazide complexes by using lithium hexamethyldisilazide as a base in 2017 (Scheme 15) [29]. The initially formed NHC–CuCl complexes 41, 44, and 47 reacted with another molecule of LiN(SiMe3)2 to undergo nucleophilic substitution of Cl by a bis(trisilyl)amino group to furnish

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

• also achieved in the last step (Figure 5) [73]. DIBALH (diisobutylaluminium hydride) in toluene was added to hexadecanol in dichloromethane at 0 °C (Figure 5) to form in situ a lithium alcoholate. Then, S-glycidol was added at rt to produce in 50% yield the diol 5.2 after a regioselective opening of

• the epoxide. The lithium salts were removed by washing with potassium sodium tartrate (Seignette’s salt). Then, at low temperature an excess of 2-chloro-1,3,2-dioxaphospholane (5.3, 3.8 equiv) in the presence of diisopropylethylamine (DIPEA) reacted with the primary alcohol to produce, after an

• presence of dimethylaminopyridine (DMAP). Then, 27.2 reacted with potassium thioacetate to produce the thioester 27.3. Its reduction with lithium aluminium hydride produced the free thiol 27.4 that was used as nucleophile on octadecyl iodide to install the C18 lipid chain. The deprotection of the primary

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

• various acids with lead(IV) tetraacetate in the presence of lithium chloride (Scheme 4) [40][41]. Nucleophilic lithium chloride was used as the chlorine atom source for this transformation. In the representative scope of this transformation, primary and secondary chlorides could be formed in relatively

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

• discharge and charge the donor-containing organic phase (Figure 2A) [34]. The first solution contained an organic lithium salt and a hydrogen-evolution catalyst which could generate hydrogen via a light-driven or dark process. The second solution contained an organic chloride salt and a water oxidation

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

• half potential (*E1/2 = −3.36 V vs SCE) even more negative than alkali metals including lithium, making it one of the most potent chemical reductants ever reported. Owing to this exceptional reductive redox power, hydrodehalogenation of various electron-poor and electron-rich aryl bromides and

• direct application of commercially available potassium (poly)sulfide (K2Sx) with H2O, the top-down generation from elemental sulfur (S8) with sodium tert-butoxide (NaOt-Bu), and the bottom-up generation from lithium sulfide (Li2S) or triisopropylsilanethiol (iPr3SiSH) were all suitable methods of