Sulfate radical anion-induced benzylic oxidation of N-(arylsulfonyl)benzylamines to N-arylsulfonylimines

• Joydev K. Laha,
• Pankaj Gupta and
• Amitava Hazra

Beilstein J. Org. Chem. 2023, 19, 771–777, doi:10.3762/bjoc.19.57

• their unique stability, defined reactivity, and versatility in organic synthesis [2]. Leveraging their electron-deficient nature, N-arylsulfonylimines are widely used in organic transformations including nucleophilic addition, cycloaddition, imino-aldol reaction, ene reactions, aza-Friedel–Crafts

• nucleophilic addition and as a result the corresponding cyclized product is not formed. The synthesis of these nitrogen heterocycles signifies the innate ability of in situ-generated N-arylsulfonylimines in a variety of reactions with various ortho-substituted anilines without the need for pre-isolation or

• -arylsulfonylimine 2, generated in situ from the corresponding N-(arylsulfonyl)benzylamine 1, undergoes transimination with the ortho-substituted aniline 3 to form imine 3ab via 3aa. Subsequent intramolecular nucleophilic addition in imine 3ab produces intermediate 3ac, which upon oxidation delivers the desired N

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

• yields with moderate to good diastereoselectivities via Michael addition and nucleophilic addition–elimination (Scheme 17) [39]. The synthesis is a [5 + 2] annulation fashion. The reactions of 2-phenyl/alkoxy-4H-benzo[d][1,3,2]dioxaphosphinin-4-ones 82 and dialkyl 2-benzylidenemalonates 78 produced

• '-carboxylates 83 in 5–10% yield as byproducts. The major products 84 were generated via Michael addition and the nucleophilic addition–elimination of the carbanion of the generated enolate moiety, while the oxyanion of the enolate moiety attacked the phosphorus to form the byproducts 83 (Scheme 18) [40][41

• -[1,1'-binaphthalen]-2-ol (97) with n-BuLi and TMEDA followed by addition of phenylphosphonic dichloride generated a pair of diastereomeric (M,4R)-4-phenyl-5H-dinaphtho[2,1-d:1',2'-f][1,2]oxaphosphepine 4-oxides 98 and 99 in low yields and low diastereoselectivity via double nucleophilic addition

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

• direction of nucleophilic addition of alcohols to FPD species was observed earlier on the example of 5-oxa-FPDs II and was found to be reversible [33][53][54]. We isolated products 5a,b,e to study their chemical behavior in solutions. We found that when compounds 5a,b,e were dissolved in anhydrous solvents

A new oxidatively stable ligand for the chiral functionalization of amino acids in Ni(II)–Schiff base complexes

• Alena V. Dmitrieva,
• Oleg A. Levitskiy,
• Yuri K. Grishin and
• Tatiana V. Magdesieva

Beilstein J. Org. Chem. 2023, 19, 566–574, doi:10.3762/bjoc.19.41

• techniques; for details, see Supporting Information File 1); [α]D20 = 2127 (MeOH). To test the stereocontrolling efficiency of the new ligand L7 and to obtain new cysteine Ni–Schiff base derivatives (RCysNi)L7 which are of practical interest, complex (ΔAlaNi)L7 was involved in a nucleophilic addition as

• stereoselectivity level. Additionally, Schiff base derivatives of L7 have a considerably higher solubility in acetonitrile as compared to the L4-based complexes (see Table 3 and Supporting Information File 1); this makes it easier to scale-up the synthesis (e.g., for the SN2 alkylations or nucleophilic addition

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

• coordinate to the bicyclic alkene forming 91. Migratory insertion of the olefin affords 92 which undergoes intramolecular nucleophilic addition followed by protodemetalation and elimination of MHP to afford 94. Base-mediated ring opening of the bridging ether generates 95 which undergoes an elimination

Investigation of cationic ring-opening polymerization of 2-oxazolines in the “green” solvent dihydrolevoglucosenone

• Solomiia Borova and
• Robert Luxenhofer

Beilstein J. Org. Chem. 2023, 19, 217–230, doi:10.3762/bjoc.19.21

• which interfere with the cationic ring-opening polymerization of 2-oxazolines (Figure 5). It has been reported that DLG can undergo keto–enol tautomerism and form enols or can participate in nucleophilic addition reactions [49]. Furthermore, it can react with water to its hydrated form, a geminal diol

Redox-active molecules as organocatalysts for selective oxidative transformations – an unperceived organocatalysis field

• Elena R. Lopat’eva,
• Igor B. Krylov,
• Dmitry A. Lapshin and
• Alexander O. Terent’ev

Beilstein J. Org. Chem. 2022, 18, 1672–1695, doi:10.3762/bjoc.18.179

• promotes the formal hydride transfer from the substrate, resulting in the formation of the hydroxylamine and substrate-derived iminium cation, which undergoes nucleophilic addition. Amine cation radical catalysis The single-electron oxidation of amines leads to amine cation radicals. Amine cation radicals

Synthetic study toward the diterpenoid aberrarone

• Liang Shi,
• Zhiyu Gao,
• Yiqing Li,
• Yuanhao Dai,
• Yu Liu,
• Lili Shi and
• Hong-Dong Hao

Beilstein J. Org. Chem. 2022, 18, 1625–1628, doi:10.3762/bjoc.18.173

• for this facile transformation might proceed with first hydrogenation followed by the substitution of the labile triflate ester (for details, see Supporting Information File 1). Moving forward, compound 17 was further converted into alkynone 9 through DIBAL-H reduction, nucleophilic addition and Dess

Formal total synthesis of macarpine via a Au(I)-catalyzed 6-endo-dig cycloisomerization strategy

• Jiayue Fu,
• Bingbing Li,
• Zefang Zhou,
• Maosheng Cheng,
• Lu Yang and
• Yongxiang Liu

Beilstein J. Org. Chem. 2022, 18, 1589–1595, doi:10.3762/bjoc.18.169

• trimethylsilylacetylene was performed to furnish aldehyde 3 [17][18] in 89% yield. A following nucleophilic addition reaction of aldehyde 3 by methylmagnesium bromide (MeMgBr) gave alcohol 4 in 99% yield, which was oxidized by pyridinium chlorochromate (PCC) leading to the formation of ketone compound and the

Functionalization of imidazole N-oxide: a recent discovery in organic transformations

• Koustav Singha,
• Imran Habib and
• Mossaraf Hossain

Beilstein J. Org. Chem. 2022, 18, 1575–1588, doi:10.3762/bjoc.18.168

• 27. Here, heteroaromatic, aromatic, and aliphatic aldehydes along with formaldehyde were taken into consideration providing the corresponding products in 33–76% yield (Scheme 6). Based on the plausible mechanism proposed by the authors, most likely the reaction began with the nucleophilic addition

• . Transition-metal-free three-component reactions, cycloaddition reaction methodology and nucleophilic addition reaction, mainly these three types of reaction methodologies can be found in the literature reports. The approaches were greener and the reaction conditions were milder or not harsh in most of the

Simple synthesis of multi-halogenated alkenes from 2-bromo-2-chloro-1,1,1-trifluoroethane (halothane)

• Yukiko Karuo,
• Atsushi Tarui,
• Kazuyuki Sato,
• Kentaro Kawai and
• Masaaki Omote

Beilstein J. Org. Chem. 2022, 18, 1567–1574, doi:10.3762/bjoc.18.167

• 2n was 32% (Table 2, entry 13). In the case of aminophenol (3o), nucleophilic addition occurred predominantly at the phenoxide position and the product was obtained in moderate yield (Table 2, entry 14). An aryl iodide also participated in the reaction (Table 2, entry 15). We propose the reaction

A facile approach to spiro[dihydrofuran-2,3'-oxindoles] via formal [4 + 1] annulation reaction of fused 1H-pyrrole-2,3-diones with diazooxindoles

• Pavel A. Topanov,
• Anna A. Maslivets,
• Maksim V. Dmitriev,
• Irina V. Mashevskaya,
• Yurii V. Shklyaev and
• Andrey N. Maslivets

Beilstein J. Org. Chem. 2022, 18, 1532–1538, doi:10.3762/bjoc.18.162

• formal [4 + 1] cycloaddition (Scheme 1). Results and Discussion FPDs are highly reactive compounds [25][26] containing an highly electrophilic enone fragment which facilitates the course of cycloaddition and nucleophilic addition reactions. In recent years, some types of cycloaddition reactions were

Ferrocenoyl-adenines: substituent effects on regioselective acylation

• Mateja Toma,
• Gabrijel Zubčić,
• Jasmina Lapić,
• Senka Djaković,
• Davor Šakić and
• Valerije Vrček

Beilstein J. Org. Chem. 2022, 18, 1270–1277, doi:10.3762/bjoc.18.133

• no case, however, the ferrocenoylation reaction at the N6 position was observed in 1H NMR spectra. This is expected, as the nucleophilic addition pathway involving the quaternary ammonium intermediate is not viable. In all purine anions, according to the calculated Fukui functions f–, the N7 atom is

• for the reaction between N6-substituted adenine anions 1–5 and FcCOCl. In no case the tetrahedral intermediate, typical of a nucleophilic addition–elimination pathway, was located as a genuine minimum on the potential energy landscape. Instead, the structure with tetrahedral geometry corresponds to

Modular synthesis of 2-furyl carbinols from 3-benzyldimethylsilylfurfural platforms relying on oxygen-assisted C–Si bond functionalization

• Sebastien Curpanen,
• Per Reichert,
• Gabriele Lupidi,
• Giovanni Poli,
• Julie Oble and
• Alejandro Perez-Luna

Beilstein J. Org. Chem. 2022, 18, 1256–1263, doi:10.3762/bjoc.18.131

• activation [19]. Thereby, C3-triorganosilyl-substituted furfurals could be suitable platforms to develop a two-step modular approach to 3-substituted 2-furyl carbinols, entailing nucleophilic addition to the aldehyde function and oxygen-assisted electrophilic substitution of the C–Si bond (Scheme 1). Results

A one-pot electrochemical synthesis of 2-aminothiazoles from active methylene ketones and thioureas mediated by NH₄I

• Shang-Feng Yang,
• Pei Li,
• Zi-Lin Fang,
• Sen Liang,
• Hong-Yu Tian,
• Bao-Guo Sun,
• Kun Xu and
• Cheng-Chu Zeng

Beilstein J. Org. Chem. 2022, 18, 1249–1255, doi:10.3762/bjoc.18.130

• produce α-iodo ketone with the molecular I2 produced by anodic oxidation. Subsequently, the nucleophilic substitution between intermediate 4 and thiourea tautomer gives α-sulfur substituted ketone 5. Intermediate 5 undergoes intramolecular nucleophilic addition to the carbonyl group and followed by

Vicinal ketoesters – key intermediates in the total synthesis of natural products

• Marc Paul Beller and
• Ulrich Koert

Beilstein J. Org. Chem. 2022, 18, 1236–1248, doi:10.3762/bjoc.18.129

• : preussochromones E and F. Review 1. α-Ketoesters as key intermediates: (+)-Euphorikanin A In the final step of the synthesis of (+)-euphorikanin A (16), an ingenane-derived diterpenoid with a 5/6/7/3-fused tetracyclic carbon skeleton, Carreira et al. used an intramolecular nucleophilic addition of an alkenyl metal

• natural product preussochromone D (30) reported by Koert et al. [13]. The synthesis commenced with the efficient production of alcohol 26 from 5-hydroxy-4H-chromen-4-one (25, Scheme 5) [14]. The ketoester moiety was build up via oxidation and nucleophilic addition of methyl diazoacetate, yielding alcohol

• -ketoester 62, followed by nucleophilic addition of isopropenylmagnesium bromide to give α-hydroxyester 63 in excellent yield and diastereoselectivity. Eight additional steps gave the bicyclic compound 64 which was already known from previous camptothecin syntheses. Isoretronecanol The α-ketoester moiety can

Experimental and theoretical studies on the synthesis of 1,4,5-trisubstituted pyrrolidine-2,3-diones

• Nguyen Tran Nguyen,
• Vo Viet Dai,
• Nguyen Ngoc Tri,
• Luc Van Meervelt,
• Nguyen Tien Trung and
• Wim Dehaen

Beilstein J. Org. Chem. 2022, 18, 1140–1153, doi:10.3762/bjoc.18.118

• antibacterial and antifungal activities [39][40][41]. The presence of an acyl group at the 4-position enables these heterocycles to be functionalized via nucleophilic addition reactions between the carbonyl group and nucleophiles like hydroxylamine and semicarbazide [42]. Herein, we report the synthesis of 4

Molecular diversity of the base-promoted reaction of phenacylmalononitriles with dialkyl but-2-ynedioates

• Hui Zheng,
• Ying Han,
• Jing Sun and
• Chao-Guo Yan

Beilstein J. Org. Chem. 2022, 18, 991–998, doi:10.3762/bjoc.18.99

• base to catalyze the C–C bond formation via a Michael addition of active methylene groups [31]. Therefore, in the presence of TBAB, the bromide assisted with the deprotonation of the phenacylmalononitrile to give a carbanion intermediate A. Secondly, the nucleophilic addition of carbanion A to electron

• exist in cis-position. Sequentially, nucleophilic addition of the amino group of intermediate F to the C–C double bond connecting the two alkoxycarbonyl groups in molecule 3 resulted in the formation of intermediate G. At last, the base-catalyzed dehydration and elimination of hydrocyanide gave the

Synthetic strategies for the preparation of γ-phostams: 1,2-azaphospholidine 2-oxides and 1,2-azaphospholine 2-oxides

• Jiaxi Xu

Beilstein J. Org. Chem. 2022, 18, 889–915, doi:10.3762/bjoc.18.90

• by two step hydrolysis gave the same product 223 in 28% yield. Phosphorus tribromide first reacted with more nucleophilic amide nitrogen atom to form dibromophosphanamine derivative 224 by loss of HBr. The more nucleophilic dibromophosphanamine derivative 224 further underwent a nucleophilic addition

Tri(n-butyl)phosphine-promoted domino reaction for the efficient construction of spiro[cyclohexane-1,3'-indolines] and spiro[indoline-3,2'-furan-3',3''-indolines]

• Hui Zheng,
• Ying Han,
• Jing Sun and
• Chao-Guo Yan

Beilstein J. Org. Chem. 2022, 18, 669–679, doi:10.3762/bjoc.18.68

• this work. Firstly, the nucleophilic addition of tributylphosphine to the bis-chalcone gives the active zwitterionic species (A). Secondly, the Michael addition of the zwitterionic species (A) to isatylidene malononitrile at the C3-position of the oxindole scaffold results in adduct (B). Thirdly, the

• reaction, the nucleophilic addition of the zwitterion (A) to this compound takes place at the exocyclic position giving the adduct (E), which in turn proceeds with the intermediates (F) and (G) according to the above mentioned similar processes to give the spiro compound 5. The different addition direction

Synthesis of 3,4,5-trisubstituted isoxazoles in water via a [3 + 2]-cycloaddition of nitrile oxides and 1,3-diketones, β-ketoesters, or β-ketoamides

• Md Imran Hossain,
• Md Imdadul H. Khan,
• Seong Jong Kim and
• Hoang V. Le

Beilstein J. Org. Chem. 2022, 18, 446–458, doi:10.3762/bjoc.18.47

• the nucleophilic addition and successive cyclization to happen. In addition, we further explored the scope of substrates with a trifluoromethyl group, a strong electron-withdrawing substituent, instead of methyl, an electron-donating group, in the 1,3-diketone starting materials (Table 2). The

Cs₂CO₃-Promoted reaction of tertiary bromopropargylic alcohols and phenols in DMF: a novel approach to α-phenoxyketones

• Ol'ga G. Volostnykh,
• Olesya A. Shemyakina,
• Anton V. Stepanov and
• Igor' A. Ushakov

Beilstein J. Org. Chem. 2022, 18, 420–428, doi:10.3762/bjoc.18.44

• )pyrroles [15]. The CsF-promoted nucleophilic addition of isocyanides to bromoacetylenes furnished the functionalized bromovinyl amides followed by Pd-catalyzed formation of 5-iminopyrrolone [16]. Sequential nucleophilic addition/intramolecular cyclization of amidine with bromoacetylenes led to imidazoles

Organocatalytic asymmetric nitroso aldol reaction of α-substituted malonamates

• Ekta Gupta,
• Narendra Kumar Vaishanv,
• Sandeep Kumar,
• Raja Krishnan Purshottam,
• Ruchir Kant and
• Kishor Mohanan

Beilstein J. Org. Chem. 2022, 18, 217–224, doi:10.3762/bjoc.18.25

• thiourea moiety with the oxygen of the nitrosobenzene. The tertiary amine, present in the catalyst acts as a base in assisting the deprotonation of the highly acidic malonamate to generate the corresponding enolate. Subsequently, a face-selective nucleophilic addition of the enolate to nitroso selective

1,2-Naphthoquinone-4-sulfonic acid salts in organic synthesis

• Ruan Carlos B. Ribeiro,
• Patricia G. Ferreira,
• Amanda de A. Borges,
• Luana da S. M. Forezi,
• Fernando de Carvalho da Silva and
• Vitor F. Ferreira

Beilstein J. Org. Chem. 2022, 18, 53–69, doi:10.3762/bjoc.18.5

• with reddish hues. The reaction with aniline forms the substitution product of the sulfonic group with a phenylamino group in a 90% yield. In his study, he proposed that the structure of the nucleophilic addition product was tautomer 19 (Scheme 1B). In search of a reagent that could form stable adducts

A photochemical C=C cleavage process: toward access to backbone N-formyl peptides

• Haopei Wang and
• Zachary T. Ball

Beilstein J. Org. Chem. 2021, 17, 2932–2938, doi:10.3762/bjoc.17.202

• give amide 12 with a half-life (t1/2) of 6.4 h. The observation of N-formyl products can be rationalized with a bifurcating mechanism (Figure 5). Following photoactivation, H-atom abstraction and nucleophilic addition of water would produce the key intermediate B. Such hemi-aminal compounds would be