Z-Selective semihydrogenation of alkynes via Ni/Lewis acid synergistic catalyzed system using DMF as hydrogen source and solvent

• Lei Kang,
• Haifeng Gao and
• Luo Yang

Beilstein J. Org. Chem. 2026, 22, 1004–1012, doi:10.3762/bjoc.22.79

• dual-catalytic system has been developed for the Z-selective semihydrogenation of alkynes. Utilizing DMF as both the hydrogen donor and reaction medium, this method affords Z-alkenes in high yield with excellent stereoselectivity under mild conditions. The protocol employs cost-effective and readily

• of alkynes using a synergistic Ni/Lewis acid dual-catalytic system. The protocol employs DMF as a combined solvent and hydrogen donor, operating under mild conditions without external reductants or pressurized equipment. This method delivers Z-alkenes in high yields (up to 95%) with excellent

• a colorless solid in 95% isolated yield (34.4 mg). The Z/E ratio (98:2) was determined by GC analysis of the crude mixture. NiCl2/Zn(AcO)2·2H2O-co-catalyzed Z-selective semihydrogenation of internal alkynes to Z-internal alkenes. NiCl2/Zn(AcO)2·2H2O-co-catalyzed semihydrogenation of terminal alkynes

Electrochemical reduction of unsaturated carbon–carbon bonds via 3d transition-metal catalysis

• Geon Kang,
• Minki Jeon,
• Pooja Kumari Jat,
• Cheoljae Kim and
• Isaac Choi

Beilstein J. Org. Chem. 2026, 22, 955–981, doi:10.3762/bjoc.22.75

• unsaturated C–C bonds, enabling precise control without molecular hydrogen or stoichiometric reductants. This review summarizes recent advances in iron-, cobalt-, and nickel-catalyzed electroreduction of alkynes and alkenes, highlighting how electrochemical parameters and catalyst design unlock distinct

• ; electroorganic synthesis; reaction mechanism; 3d transition metals; unsaturated C–C bonds; Introduction Reductions of unsaturated C–C bonds Reduction of unsaturated C–C bonds, most notably, alkynes and alkenes, is a synthetic method that has been widely and extensively discussed with a long and rich history

• among chemistry and chemical industry community [1][2][3][4][5][6][7][8][9]. Given this longstanding significance, the development of controlled reduction strategies has diversified to accommodate the distinct reactivity and selectivity. Representatively, complete hydrogenation of alkynes or alkenes is

Recent advances in copper-catalyzed direct hydroamination of alkenes with (hetero)aromatic amines

• Hyejeong Lee and
• Yunmi Lee

Beilstein J. Org. Chem. 2026, 22, 925–947, doi:10.3762/bjoc.22.73

• pharmaceuticals and functional materials, making efficient C–N bond formation a fundamental transformation in synthetic chemistry. The direct hydroamination of alkenes using (hetero)aromatic N–H nucleophiles offers an atom- and step-economical strategy; however, the reduced nucleophilicity and distinct

• , and functional group tolerance. This review summarizes recent advances in the copper-catalyzed hydroamination of alkenes with (hetero)aromatic N–H nucleophiles, emphasizing the mechanistic paradigms and the factors governing selectivity. Keywords: aromatic amines; aza-Michael addition; Cu catalysis

• ]. Hydroamination simultaneously forms C–N and C–H bonds from simple and readily available starting materials without prefunctionalization. When applied to electron-deficient alkenes such as α,β-unsaturated carbonyl compounds, nitroalkenes, or vinyl sulfones, this transformation is often categorized as an aza

Diastereodivergent electrophilic trapping of α-boryl lithium derivatives

• Tereza Pavlíčková,
• Noam Orbach and
• Ilan Marek

Beilstein J. Org. Chem. 2026, 22, 882–887, doi:10.3762/bjoc.22.68

• ; Introduction α-Boryl carbanions 1 (Scheme 1), also referred to as boron alkylidenes or borata alkenes, represent a fascinating class of organoboron intermediates characterized by the delocalization of electron density from the negatively charged carbon center toward the electron-deficient boron atom. This

The trans-influence in gold chemistry from a catalytic perspective

• Manfred Bochmann

Beilstein J. Org. Chem. 2026, 22, 838–856, doi:10.3762/bjoc.22.66

• calculations. Using the same radical-initiated approach it was also possible to realise gold hydride insertions of alkenes [65] and of isocyanides (Scheme 11) [66]. A different reactivity was observed for C^C-stabilised hydrides, with H trans to anionic C. The complexes (C^C)AuH(L) 19 (L = PMe3, Ptol3) and [(C

• ]. The same principles apply to other alkenes and nucleophiles (alcohols, water) [85]. Using acetylene instead of ethylene gives first the analogous mono-insertion product, with the vinyl ligand trans to N. The mono-vinyl complex (C trans to N) could be isolated. Adding excess acetylene led to the

• been claimed to explain the (MeDalPhos)Au-catalysed synthesis of Heck-type olefins, including migratory alkene 2,1-insertion into a Au–aryl bond, followed by β-H elimination, to give non-conjugated benzyl alkenes [94]. This reactivity scenario has been extended to include chain walking [95]. The main

Synthesis and biological evaluation of new brassinosteroid analogs with C-22 benzoate function

• María Núñez,
• Camila Escobar,
• Mario Párraga,
• Mauricio Soto,
• Luis Espinoza-Catalán,
• Katy Díaz and
• Andrés F. Olea

Beilstein J. Org. Chem. 2026, 22, 753–762, doi:10.3762/bjoc.22.57

• HSQC NMR and 1H,13C HMBC NMR spectra data, respectively (Figures S35 and S36, Supporting Information File 1). Previous studies have shown that Sharpless dihydroxylation of 2,3-steroidal alkenes with OsO4/DHQD-CLB system, leads to formation of "cis" glycols with C-2(R) and C-3(S) stereochemistry in the

Synthesis of heterocycles based on azomethine ylides from α-amino acids (or amines) and carbonyl compounds

• Ekaterina V. Berezhnaya,
• Alexander I. Ponyaev,
• Vitali M. Boitsov and
• Alexander V. Stepakov

Beilstein J. Org. Chem. 2026, 22, 705–741, doi:10.3762/bjoc.22.55

• Federation Saint Petersburg State University, Universitetskaya nab. 7/9, 199034, St. Petersburg, Russian Federation 10.3762/bjoc.22.55 Abstract This review focuses on new directions in (3 + 2) cycloaddition of azomethine ylides to alkenes, resulting in the formation of fused or spiro-fused pyrrolidine

• from imino esters, catalyzed by chiral Cu(I,II) and Ag(I) complexes, are widely used. Reactions using α-amino acids proceed, in most cases, without the use of catalysts, with high yields and high stereoselectivity. Electrophilic alkenes of various structures, (hetero)aromatic olefins and benzofulvenes

• , cyclic and acyclic unsaturated substrates, and fullerenes are useful dipolarophiles. This reaction method allows for the single-step creation of a wide variety of complex polyheterocyclic systems that may be useful for practical applications. Keywords: alkenes; α-amino acids; azomethine ylides; carbonyl

Regioselective approach to 5-arylsulfonylisoxazoles and their antimicrobial activity

• Artem S. Sazonov,
• Dmitry A. Vasilenko,
• Denis V. Porfiriev,
• Yuri K. Grishin,
• Rimma A. Gazzaeva,
• Alisa P. Chernyshova,
• Maxim A. Kryakvin,
• Anna A. Baranova,
• Vera A. Alferova and
• Elena B. Averina

Beilstein J. Org. Chem. 2026, 22, 592–602, doi:10.3762/bjoc.22.45

• common method for the synthesis of substituted isoxazoles is based on the 1,3-dipolar cycloaddition of nitrile oxide with alkynes or alkenes followed by oxidation of the resulting isoxazoline product in the latter case [18][19][20][21][22]. This approach, in three variations, is also applicable to obtain

• oxide reacts with 1,2-disubstituted alkenes containing a sulfonyl group to form 4,5-dihydroisoxazoles, which are then oxidized with chloranil to provide isoxazole [23] (approach A). Another synthetic protocol involves the 1,3-dipolar cycloaddition of nitrile oxide to 1-bromo-1-EWG-alkenes, resulting in

Dialkylaminoalkylation of β-ketosulfones via ring-opening of 3-sulfonylpyrrolidines

• Evgeny M. Buev,
• Alexander V. Pavlushin,
• Vladimir S. Moshkin and
• Vyacheslav Y. Sosnovskikh

Beilstein J. Org. Chem. 2026, 22, 383–389, doi:10.3762/bjoc.22.26

• ][18][19]. Among the various types of aminoalkylations, aminomethylation reactions have been the most extensively studied and applied significantly to aromatic [20] and CH-acidic compounds [21], alkanes [22][23], olefines [24][25] and electron-withdrawing alkenes [26][27]. This rapidly growing research

Arene activation via π-bond localization: concepts and opportunities

• Paul Meiners,
• Julian J. Melder and
• Tobias Morack

Beilstein J. Org. Chem. 2026, 22, 257–273, doi:10.3762/bjoc.22.19

• (Figure 6C), so suitable aromatic ligands are limited to those lacking strongly π-acidic functional groups, e.g., alkenes, alkynes, aldehydes, certain ketones, and nitriles. Lewis-basic heteroarenes, such as pyridines or imidazoles, tend to coordinate via nitrogen instead, disfavoring η2-binding (Figure

• η2-arene complexes and alkenes are well-established (Scheme 4A) [65][66], analogous transformations with alkyne dienophiles had remained elusive. Oxidative liberation of the resulting complexes furnished several unprecedented free barrelenes (Scheme 4B). Intriguingly, η2-coordination of barrelenes to

• reactions of η2-arene complexes with alkenes and alkynes; NMM: N-methylmaleimide [64][65]. Binding characteristics and pioneering examples of isolable η3-benzyl complexes. p-Selective allylation of benzyl chlorides with allylstannanes and subsequent synthetic expansion of dearomative cross-coupling

Synthesis of diaryl phosphates using phytic acid as a phosphorus source

• Kazuya Asao,
• Seika Matsumoto,
• Haruka Mori,
• Riku Yoshimura,
• Takeshi Sasaki,
• Naoya Hirata,
• Yasuyuki Hayakawa and
• Shin-ichi Kawaguchi

Beilstein J. Org. Chem. 2026, 22, 213–223, doi:10.3762/bjoc.22.15

• the other mechanism is based on an E2 reaction, which involves the elimination of phosphoric acid accompanied by alkene formation. The phosphoric acid ester of a secondary alcohol releases phosphoric acid and alkenes through thermal degradation, which has been previously observed using isosorbide

Highly electrophilic, gem- and spiro-activated trichloromethylnitrocyclopropanes: synthesis and structure

• Ilia A. Pilipenko,
• Mikhail V. Grigoriev,
• Olga Yu. Ozerova,
• Igor A. Litvinov,
• Darya V. Spiridonova,
• Aleksander V. Vasilyev and
• Sergey V. Makarenko

Beilstein J. Org. Chem. 2026, 22, 123–130, doi:10.3762/bjoc.22.5

• a CF3-containing substrate and a nitromethylene component (the tandem reaction of trifluoromethyl-substituted alkenes with nitromethane [34] or bromonitromethane derivatives [35][36]) (Scheme 1). At the same time, one of the methods of synthesis of vicinally substituted nitrocyclopropanes is the

Synthesis and applications of alkenyl chlorides (vinyl chlorides): a review

• Daniel S. Müller

Beilstein J. Org. Chem. 2026, 22, 1–63, doi:10.3762/bjoc.22.1

• stereocontrolled olefin metathesis with molybdenum catalysts to access trisubstituted alkenes including alkenyl chlorides (Figure 3H) [39]. Two recent reviews by Lu [40] and Nishiwaki [41] provide overviews of current developments in the hydrochlorination of alkynes, highlighting emerging catalytic strategies

• anion). Generation of tertiary aliphatic cations and intramolecular trapping with alkenes or alkynes is well known in the context of polyene cyclizations [155]. Building on Johnson’s earlier work (Scheme 48A) [156], Fañanás and Rodríguez developed an intramolecular cationic cyclization strategy to

• reactions for 1,1-dichloroalkenes (e.g., compound 273, Scheme 53) [182]. However, as noted by Negishi, this procedure results in mixtures or exclusively dialkylation products when applied to alkyl-substituted 1,1-dichloro-1-alkenes. Negishi and co-worker reported an improved version of the procedure using

Mechanistic insights into hydroxy(tosyloxy)iodobenzene-mediated ditosyloxylation of chalcones: a DFT study

• Jai Parkash,
• Sangeeta Saini,
• Vaishali Saini,
• Omkar Bains and
• Raj Kamal

Beilstein J. Org. Chem. 2025, 21, 2703–2715, doi:10.3762/bjoc.21.208

• -substituents; α,β-unsaturated carbonyl compounds; Introduction Hypervalent iodine compounds exhibit a range of bonding patterns which making these compounds powerful reagents or catalysts for a number of organic transformations [1][2][3][4] – oxidation of alcohols [5], epoxidation of alkenes [6], oxidative

• dearomatization [7], amination [8], oxidative coupling [9], ring contraction [10][11][12], oxidative rearrangement [13][14][15], dihydroxylation of alkenes, arylation [16], oxidation of sulfides [17] and many more. These hypervalent compounds contain iodine in higher oxidation state than its usual −(I) valence

• , however, a number of studies also report the formation of a carbenium ion as an alternate pathway, typically for the oxidation of alkenes with phenyl substituents on carbon–carbon double bonds [10][11][12][29][34][35]. Here, Scheme 1 depicts the reaction investigated in the current study which is, HTIB

Tandem hydrothiocyanation/cyclization of CF₃-iminopropargyl alcohols with NaSCN in the presence of AcOH

• Ruslan S. Shulgin,
• Ol’ga G. Volostnykh,
• Anton V. Stepanov,
• Igor’ A. Ushakov,
• Alexander V. Vashchenko and
• Olesya A. Shemyakina

Beilstein J. Org. Chem. 2025, 21, 2694–2702, doi:10.3762/bjoc.21.207

• The hydrofunctionalization of alkynes is one of the most effective and convenient ways of synthesizing polysubstituted alkenes [1][2][3][4][5]. Such reactions can also afford more complex products, provided that the vinyl intermediates formed during the reaction undergo further transformations [6][7

Visible-light-driven NHC and organophotoredox dual catalysis for the synthesis of carbonyl compounds

• Vasudevan Dhayalan

Beilstein J. Org. Chem. 2025, 21, 2584–2603, doi:10.3762/bjoc.21.200

• , and aryloxymethyl potassium trifluoroborate salt 10 under mild conditions. The described catalytic system exhibited broad functional group tolerance and efficiently employed terminal alkenes 11 to generate quaternary centers adjacent to the carbonyl group. The key step in this organocatalytic process

• conditions. This visible-light-mediated dual catalytic method permits the efficient acylsilylation of substituted terminal alkenes 11 via NHC catalysis. Remarkably, this method afforded silyl radicals, which are typically difficult to prepare using conventional HAT-based catalytic methods. This method is

• for 18 h (Scheme 6) [56]. Gao, Ye, and co-workers reported the iminoacylation of alkenes 17 via photoredox NHC dual catalysis in the presence of NHC (20 mol %), photocatalyst (5 mol %), with Na2CO3 (1.2 equiv) using a 36 W blue LED. In this method, the alkene-attached iminyl radicals A and the NHC

Transformation of the cyclohexane ring to the cyclopentane fragment of biologically active compounds

• Natalya Akhmetdinova,
• Ilgiz Biktagirov and
• Liliya Kh. Faizullina

Beilstein J. Org. Chem. 2025, 21, 2416–2446, doi:10.3762/bjoc.21.185

• contraction is demonstrated by the example of converting organoborane intermediates into alcohols, amines, and E-alkenes (Scheme 32). 4 Meinwald rearrangements of epoxides The rearrangements of oxiranes annelated to cyclohexane occupy an important place in the synthesis of cyclopentanes due to the

An Fe(II)-catalyzed synthesis of spiro[indoline-3,2'-pyrrolidine] derivatives

• Elizaveta V. Gradova,
• Nikita A. Ozhegov,
• Roman O. Shcherbakov,
• Alexander G. Tkachenko,
• Larisa Y. Nesterova,
• Elena Y. Mendogralo and
• Maxim G. Uchuskin

Beilstein J. Org. Chem. 2025, 21, 2383–2388, doi:10.3762/bjoc.21.183

• , a highly diastereoselective method for the synthesis of dihydrospiro[indoline-3,2'-pyrrole]-2-ones has been developed (Scheme 1, path a) [7]. This transformation proceeds via a Lewis acid-mediated conjugate addition of vinyl azides to electron-deficient alkenes, followed by denitrogenative

• under heating furnished chiral spiroindolylpyrroles in excellent yields and enantioselectivity (Scheme 1, path d) [11]. Moreover, a copper-catalyzed reaction of oxindole-derived alkenes with acetophenone O-acetyl oxime has also been employed to construct the spiroindolylpyrrole scaffold (Scheme 1, path

Recent advances in Norrish–Yang cyclization and dicarbonyl photoredox reactions for natural product synthesis

• Peng-Xi Luo,
• Jin-Xuan Yang,
• Shao-Min Fu and
• Bo Liu

Beilstein J. Org. Chem. 2025, 21, 2315–2333, doi:10.3762/bjoc.21.177

• singlet state, which undergoes intersystem crossing (ISC) to form the excited triplet state B. An intramolecular 1,5-hydrogen atom transfer (HAT) then ensues, producing the 1,4-diradical C, which can be converted into diverse products such as alkenes and enols (Scheme 1a). Notably, the 1,4-diradical

Enantioselective radical chemistry: a bright future ahead

• Anna C. Renner,
• Sagar S. Thorat,
• Hariharaputhiran Subramanian and
• Mukund P. Sibi

Beilstein J. Org. Chem. 2025, 21, 2283–2296, doi:10.3762/bjoc.21.174

• , a chiral Cu(III) complex forms from an achiral benzylic radical and a Cu(II)–CN species, and subsequent reductive elimination affords the enantioenriched benzylic nitrile product. Recently, X.-Y. Liu and co-workers reported an enantioselective aminofluoroalkylation of alkenes using a Cu(I)/chiral

C2 to C6 biobased carbonyl platforms for fine chemistry

• Jingjing Jiang,
• Muhammad Noman Haider Tariq,
• Florence Popowycz,
• Yanlong Gu and
• Yves Queneau

Beilstein J. Org. Chem. 2025, 21, 2103–2172, doi:10.3762/bjoc.21.165

Understanding the origin of stereoselectivity in the photochemical denitrogenation of 2,3-diazabicyclo[2.2.1]heptene and its derivatives with non-adiabatic molecular dynamics

• Leticia A. Gomes and
• Steven A. Lopez

Beilstein J. Org. Chem. 2025, 21, 2007–2020, doi:10.3762/bjoc.21.156

• starting materials for different types of reactions including thermal isomerization to cyclopentenes [36][37][38] and 1,4-pentadienes [37][38], chemical electron-transfer oxidations to cyclopentene [39] and cycloaddition reactions with electron-deficient alkenes and alkynes [38][40][41] (Scheme 1b

Photoswitches beyond azobenzene: a beginner’s guide

• Michela Marcon,
• Christoph Haag and
• Burkhard König

Beilstein J. Org. Chem. 2025, 21, 1808–1853, doi:10.3762/bjoc.21.143

• and subsequent reduction of 45 (if substrates 43 and 44 contain a NO2 group, this will also be reduced, Scheme 13A) [54], or by Wittig reaction and reduction of the isomeric mixture of alkenes 48 (Scheme 13B) [57]. Oxidation of 49 with oxone [58] or m-chloroperbenzoic acid [54] yields 35. Wittig

Fe-catalyzed efficient synthesis of 2,4- and 4-substituted quinolines via C(sp²)–C(sp²) bond scission of styrenes

• Prafull A. Jagtap,
• Manish M. Petkar,
• Vaishnavi R. Sawant and
• Bhalchandra M. Bhanage

Beilstein J. Org. Chem. 2025, 21, 1799–1807, doi:10.3762/bjoc.21.142

• promising industrial relevance. Oxidative cleavage of alkenes to yield carbonyl compounds is one of the key transformations in synthetic organic chemistry [41][42]. Over the past two decades, this field has witnessed significant advancements, primarily through the use of organic oxidants and transition

• -metal catalysts. One of the key transformations in organic synthesis is the selective oxidative cleavage of alkenes to yield ketones or aldehydes [43][44][45][46][47]. Traditionally, such transformations have been achieved using various oxidizing agents, transition-metal-based systems, organo- and

• advanced strategies have been developed for cleavage of alkenes [48][49][50][51]. Owing to the abundance and versatile applications of styrenes in diverse fields of organic chemistry, some strategies have recently been developed for synthesizing 2,4-disubstituted and 4-substituted quinoline derivatives via

Photocatalysis and photochemistry in organic synthesis

• Timothy Noël and
• Bartholomäus Pieber

Beilstein J. Org. Chem. 2025, 21, 1645–1647, doi:10.3762/bjoc.21.128

• of alkenylboronic esters using energy transfer catalysis [26]. Gualandi and co-workers leveraged a combination of photoredox and HAT catalysis to realize the intramolecular nucleophilic amidation of alkenes with β-lactams [27]. Further, Luridiana and colleagues developed a method for the alkylation