O,S,Se-containing Biginelli products based on cyclic β-ketosulfone and their postfunctionalization

• Kateryna V. Dil and
• Vitalii A. Palchykov

Beilstein J. Org. Chem. 2024, 20, 2143–2151, doi:10.3762/bjoc.20.184

• , Leishmania amazonensis, Tcruzi epimastigota, Dengue larvicida, and for selected cases Alzheimer and Sars-COVID. For more details, see Table S1 (Supporting Information File 1). Conclusion In summary, we have demonstrated the catalytic regioselective Biginelli synthesis of new S-heterocyclic systems ‒ 4-aryl

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

• base in the Knoevenagel reaction and as a component for ring formation. Cyclization is completely regioselective when arylhydrazines are used; with methylhydrazine, the ratio is greater than 10:1. In addition to malononitrile, derivatives with reduced nucleophilicity (X = CO2R) are also tolerated in

• β-ketoesters to form enaminones 85. The consecutive three-component reaction culminates in cyclization with substituted hydrazines, leading to the regioselective formation of 5-fluoroalkylpyrazoles 83 (Scheme 30) [111]. Following subsequent saponification, pyrazole-4-carboxylic acids can be obtained

• 93 (Scheme 33) [116]. The presence of two equivalents of sodium hydride deprotonates the acidic α-NH of arylhydrazine, thereby determining the regioselective attack in addition–elimination sequence furnishing a hydrazine enaminone intermediate, and ultimately leading to pyrazole 93 after cyclization

Regioselective alkylation of a versatile indazole: Electrophile scope and mechanistic insights from density functional theory calculations

• Pengcheng Lu,
• Luis Juarez,
• Paul A. Wiget,
• Weihe Zhang,
• Krishnan Raman and
• Pravin L. Kotian

Beilstein J. Org. Chem. 2024, 20, 1940–1954, doi:10.3762/bjoc.20.170

• Structural Biology, BioCryst Pharmaceuticals Inc., Discovery Center of Excellence, 2100 Riverchase Center Building 200, Suite 200 Birmingham, AL, 35244, USA 10.3762/bjoc.20.170 Abstract Herein, we report a pair of regioselective N1- and N2-alkylations of a versatile indazole, methyl 5-bromo-1H-indazole-3

• character of TsO− and triphenylphosphine oxide, precluding any thermodynamic versus kinetic arguments for regioselectivity. Conclusion We have established highly regioselective N1- and N2-alkylations of methyl 5-bromo-1H-indazole-3-carboxylate from diverse commercially available alcohols with excellent

The Groebke–Blackburn–Bienaymé reaction in its maturity: innovation and improvements since its 21st birthday (2019–2023)

• Cristina Martini,
• Muhammad Idham Darussalam Mardjan and
• Andrea Basso

Beilstein J. Org. Chem. 2024, 20, 1839–1879, doi:10.3762/bjoc.20.162

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

• synthesis of 2H-furan-3-ones from mestranol [23]. Initially, a 1,3-dipolar regioselective cycloaddition occurred between the alkyne group of mestranol and an alkanonitrile oxide generated in situ from the corresponding oxime, yielding isoxazoles 31. Later, a reductive ring cleavage of the isoxazole ring was

• decarboxylation of the carboxylic residue when heated at reflux of methanol. After the regioselective cycloadditions, spiro compounds 49a,b were obtained in yields ranging from 75% to 91% (Scheme 15). Related derivatives have similarly been achieved in good to excellent yields [32][33]. Recently, López et al

• as a 17β-HSD3 inhibitor [42]. The same research group reported a new family of 3-spiromorpholinones derived from ADT bearing hydrophobic substituents [43][62]. The synthetic key step involved a regioselective aminolysis of the oxirane 131 with different ʟ- or ᴅ-amino acids (53–99% yields) to obtain

Chemo-enzymatic total synthesis: current approaches toward the integration of chemical and enzymatic transformations

• Ryo Tanifuji and
• Hiroki Oguri

Beilstein J. Org. Chem. 2024, 20, 1693–1712, doi:10.3762/bjoc.20.151

• ]. The P450 enzyme BscF is responsible for regioselective abstraction of a hydrogen at C12 and subsequent diastereoselective hydroxylation of the radical intermediate B to produce brassicicene B (10). Meanwhile, further single-electron oxidation of the intermediate B would trigger a Wagner–Meerwein-type

• the chemo-enzymatic approach for synthesizing this family of natural products [57]. Regioselective macrocyclization: tylactone and juvenimicins In the chemical synthesis of macrolides, macrolactone construction most generally involves the generation of activated esters from the corresponding

• (Scheme 7 and Scheme 8) [68]. This chemo-enzymatic total synthesis represents a pioneering approach, as it ingeniously integrates biosynthetic intermediate mimics, synthesized through multiple steps, into the biosynthetic pathway. A cascade of stereoselective carbon chain elongation and regioselective

Methyltransferases from RiPP pathways: shaping the landscape of natural product chemistry

• Maria-Paula Schröder,
• Isabel P.-M. Pfeiffer and
• Silja Mordhorst

Beilstein J. Org. Chem. 2024, 20, 1652–1670, doi:10.3762/bjoc.20.147

• encoded in the pbt cluster of P. rosea. The thiopeptide GE2270 encoded by pbt undergoes further regioselective modification through C-methylation of thiazoles. The two rSAM MTs PbtM2 and PbtM3 methylate thiazole E and thiazole D, respectively [64]. PbtM2 and PbtM3 show substantial sequence similarities to

Synthesis of 4-functionalized pyrazoles via oxidative thio- or selenocyanation mediated by PhICl₂ and NH₄SCN/KSeCN

• Jialiang Wu,
• Haofeng Shi,
• Xuemin Li,
• Jiaxin He,
• Chen Zhang,
• Fengxia Sun and
• Yunfei Du

Beilstein J. Org. Chem. 2024, 20, 1453–1461, doi:10.3762/bjoc.20.128

• efficient method for a smooth selenocyanation of pyrazole compounds. Results and Discussion In our previous work we reported that a regioselective C-5 thiocyanation of the 2-pyridone skeleton could be realized via a PhICl2-mediated electrophilic thiocyanation approach [54]. Inspired by this previous work

Challenge N- versus O-six-membered annulation: FeCl₃-catalyzed synthesis of heterocyclic N,O-aminals

• Giacomo Mari,
• Lucia De Crescentini,
• Gianfranco Favi,
• Fabio Mantellini,
• Diego Olivieri and
• Stefania Santeusanio

Beilstein J. Org. Chem. 2024, 20, 1412–1420, doi:10.3762/bjoc.20.123

• procedures [16], our consolidated 3-CR strategy [17][18][19] implicates a careful selection of the starting components that ensures the installation of functionalities to be converged, by regioselective control, in different ring-closing processes [20][21]. With these considerations in mind and with the aim

• ), whose sequential acylation process by iso(thio)cyanates 3a–h gives rise to the asymmetric (thio)urea derivatives (intermediate II). The spontaneous nucleophilic attack of the (thio)amide nitrogen on the terminal methyl ester function at C-4 of the starting azo-ene system provides a regioselective

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

• .20.122 Abstract Hypervalent iodine catalysis has been widely utilized in olefin functionalization reactions. Intermolecularly, the regioselective addition of two distinct nucleophiles across the olefin is a challenging process in hypervalent iodine catalysis. We introduce here a unique strategy using

• nucleophiles were incorporated (Scheme 1b) [29][30][31][32][33][34][35][36][37][38][39][40]. Intermolecular hypervalent iodine catalysis with the regioselective additions of two distinct nucleophilic functionalities across an olefin, however, remains challenging with limited solutions [41][42][43][44][45][46

Domino reactions of chromones with activated carbonyl compounds

• Peter Langer

Beilstein J. Org. Chem. 2024, 20, 1256–1269, doi:10.3762/bjoc.20.108

• ) [32]. The formation of the products can be explained by Michael reaction (1,4-addition) of 3 to the chromone and ring cleavage to give intermediate G. Subsequent Knoevenagel reaction by attack of the methylene carbon to the aldehyde resulted in the formation of the final products. The regioselective

• to the chromone and ring cleavage to give intermediate I. Subsequent Knoevenagel reaction by attack of the methylene carbon to the carbonyl group adjacent to the ester group resulted in the formation of the final products. The regioselective cyclization can be explained by the higher electrophilicity

• -Ketoamides The reaction of 3-ketoamides 34a–f with 3-halochromones 15a–g afforded 2-(salicyloyl)furans 35a–x in mostly good to excellent yields (Scheme 18) [41]. The reaction proceeds by 1,4-addition of the methylene carbon of 34 to the chromone to give intermediate T, cyclization by regioselective

Competing electrophilic substitution and oxidative polymerization of arylamines with selenium dioxide

• Vishnu Selladurai and
• Selvakumar Karuthapandi

Beilstein J. Org. Chem. 2024, 20, 1221–1235, doi:10.3762/bjoc.20.105

• , regioselective aromatic electrophilic substitution is often difficult. Various synthetic strategies have evolved to address such problems and expand the scope of SeO2 beyond the oxidizing capability. Ren et al. adopted potassium-iodide-mediated catalytic selenation of aromatic compounds using SeO2 (Scheme 1) [33

Two-fold addition reaction of silylene to C₆₀: structural and electronic properties of a bis-adduct

• Masahiro Kako,
• Masato Kai,
• Masanori Yasui,
• Michio Yamada,
• Yutaka Maeda and
• Takeshi Akasaka

Beilstein J. Org. Chem. 2024, 20, 1179–1188, doi:10.3762/bjoc.20.100

• Figure 1 [5]. Diederich and co-workers developed a general methodology using tether-directed remote functionalization for the regioselective formation of multiple adducts of fullerenes [6]. In our earlier reports, the reactions of C60 and C70, with silylene Dip2Si (1, Dip = 2,6-diisopropylphenyl), a

Manganese-catalyzed C–C and C–N bond formation with alcohols via borrowing hydrogen or hydrogen auto-transfer

• Mohd Farhan Ansari,
• Atul Kumar Maurya,
• Abhishek Kumar and
• Saravanakumar Elangovan

Beilstein J. Org. Chem. 2024, 20, 1111–1166, doi:10.3762/bjoc.20.98

• and methanol as a C1 source [86]. A total of 28 desired aminomethylated aromatic products were isolated with moderate to good yields (Scheme 56). Later, Rueping and co-workers developed the regioselective alkylation of indolines with alcohols as the alkylating agent using a manganese-pincer catalyst

Carbonylative synthesis and functionalization of indoles

• Alex De Salvo,
• Raffaella Mancuso and
• Xiao-Feng Wu

Beilstein J. Org. Chem. 2024, 20, 973–1000, doi:10.3762/bjoc.20.87

• -arylindoles by reductive carbonylation of unfunctionalized nitroarenes in the presence of arylalkynes and Pd(phen)2(BF4)2 as catalyst has been demonstrated by Cenini's group. The reaction was regioselective, with no detection of 2-arylindole byproducts. No prefunctionalization of the ortho position of the

• controllable and regioselective synthesis of indol-3-α-ketoamides and indol-3-amides via the direct double- and monoaminocarbonylation of indole derivatives by using secondary amines [70]. They used Pd(dppf)Cl2 as catalyst system. The indol-3-α-ketoamides were synthesized by adding dppf as ligand, CuI as co

• -catalyst, and LiCl as additive under 40 bar of CO. To make the process regioselective towards indol-3-amides, dppf as ligand, the base (K2CO3), and I2 were added, and the reaction run under a low pressure of CO (1 bar), in addition to the catalyst. Both processes took place well in THF (Scheme 39). In 2013

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

• investigations demonstrated the ability of diaryliodonium salts for selective mono-arylation of 2-naphthols [34]. In this context, we embark on a strategy to modify the neighbouring position of the diaryliodonium salt with an ester group, presenting a novel copper-catalysed regioselective arylocyclization of

Advancements in hydrochlorination of alkenes

• Daniel S. Müller

Beilstein J. Org. Chem. 2024, 20, 787–814, doi:10.3762/bjoc.20.72

• Syntheses [83]. The proposed catalytic cycle is shown in Figure 7 and involves the following steps. First, a cobalt hydride complex A is formed in situ from Co(II) complex and the silane. Then, regioselective alkene hydrocobaltation takes place. This step is highly regioselective, placing the cobalt atom on

Synthesis of new representatives of A₃B-type carboranylporphyrins based on meso-tetra(pentafluorophenyl)porphyrin transformations

• Victoria M. Alpatova,
• Evgeny G. Rys,
• Elena G. Kononova and
• Valentina A. Ol'shevskaya

Beilstein J. Org. Chem. 2024, 20, 767–776, doi:10.3762/bjoc.20.70

• single pentafluorophenyl ring was prepared through the regioselective nucleophilic aromatic substitution reaction of the p-fluorine atoms in 5,10,15,20-tetrakis(pentafluorophenyl)porphyrin with 9-mercapto-m-carborane. The reaction of this porphyrin with sodium azide led to the selective substitution of

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

• , greatly increasing the molecular complexity of the starting substrate. Using radical chemistry would lead to a regioselective addition of azide radicals to the alkene, forming selectively the most stabilized C-centered radical. A prominent method for the generation of azide radicals relies on hypervalent

Regioselective quinazoline C2 modifications through the azide–tetrazole tautomeric equilibrium

• Dāgs Dāvis Līpiņš,
• Andris Jeminejs,
• Una Ušacka,
• Anatoly Mishnev,
• Māris Turks and
• Irina Novosjolova

Beilstein J. Org. Chem. 2024, 20, 675–683, doi:10.3762/bjoc.20.61

• [9][10] are commonly employed for quinazoline modification (Scheme 1). Existing literature underscores the reactivity of the C4 position in aromatic nucleophilic substitutions of quinazolines I while achieving regioselective replacement at the C2 position poses challenges [11]. Modification of the C2

• valuable precursors for the C2-regioselective modification in quinazolines. Furthermore, the developed methodology was valorized by successfully employing it in the synthesis of adrenoblockers terazosin and prazosin. Approaches for quinazoline modifications at the C2 and C4 positions. Attempts toward

Palladium-catalyzed three-component radical-polar crossover carboamination of 1,3-dienes or allenes with diazo esters and amines

• Geng-Xin Liu,
• Xiao-Ting Jie,
• Ge-Jun Niu,
• Li-Sheng Yang,
• Xing-Lin Li,
• Jian Luo and
• Wen-Hao Hu

Beilstein J. Org. Chem. 2024, 20, 661–671, doi:10.3762/bjoc.20.59

• reactant ratio produced the desired product 4a in 84% yield as optimal conditions for this protocol (Table 1, entry 13). With the optimized conditions obtained, we examined the generality of our palladium-catalyzed regioselective carboamination of 1,3-dienes with diazo esters and amines (Scheme 2). First

Mono or double Pd-catalyzed C–H bond functionalization for the annulative π-extension of 1,8-dibromonaphthalene: a one pot access to fluoranthene derivatives

• Nahed Ketata,
• Linhao Liu,
• Ridha Ben Salem and
• Henri Doucet

Beilstein J. Org. Chem. 2024, 20, 427–435, doi:10.3762/bjoc.20.37

• using commercially available substrates and allowing the regioselective introduction of functional groups at the desired positions is still needed. By using Pd-catalyzed double C–H bond functionalization of activated arenes, such as (poly)fluoroarenes, or by combining a palladium-catalyzed

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

• aromatic ring, forming intermediate 41, which was then oxidized to cation 42, thereby completing the photocatalytic cycle. The reaction proceeded by regioselective nucleophilic addition of H2O, accompanied by the loss of MeOH to deliver spirocycle 43. Notably, the dearomative spirocyclization of biaryl

Synthesis of π-conjugated polycyclic compounds by late-stage extrusion of chalcogen fragments

• Aissam Okba,
• Pablo Simón Marqués,
• Kyohei Matsuo,
• Naoki Aratani,
• Hiroko Yamada,
• Gwénaël Rapenne and
• Claire Kammerer

Beilstein J. Org. Chem. 2024, 20, 287–305, doi:10.3762/bjoc.20.30

• -substituted soluble precursors 3a–f owing to increased modularity (Scheme 5) [62]. To this aim, acenaphthene was selected as key building block and it underwent two successive regioselective halogenations to give bromochloroacenaphthene 8 in 64% overall yield. The latter was next converted into the

• –Alder reaction of naphthodiyne precursor 55 with isobenzofuran 61 to give monoepoxide 62 as a mixture of regioisomers. Further treatment of the latter with one equivalent of cesium fluoride allowed the regioselective Diels–Alder with the previous diene 61, to afford 63 as another mixture of position

Unveiling the regioselectivity of rhodium(I)-catalyzed [2 + 2 + 2] cycloaddition reactions for open-cage C₇₀ production

• Cristina Castanyer,
• Anna Pla-Quintana,
• Anna Roglans,
• Albert Artigas and
• Miquel Solà

Beilstein J. Org. Chem. 2024, 20, 272–279, doi:10.3762/bjoc.20.28

• Cristina Castanyer Anna Pla-Quintana Anna Roglans Albert Artigas Miquel Sola Institut de Química Computacional i Catàlisi (IQCC) and Departament de Química, Universitat de Girona (UdG), Girona 17003 Catalunya, Spain 10.3762/bjoc.20.28 Abstract The regioselective functionalization of fullerenes

• regioselective [2 + 2 + 2] cycloaddition reactions as a means to tailor the properties of fullerenes for specific applications. Types of [6,6]-bonds together with the [5,6]-bond of C60 with their C–C distances in pristine C60 and C70. 1H NMR (CS2/CDCl3, 400 MHz) spectrum of compound 2a as a mixture of two