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

• alkenyl compounds, the vinyl ether function is characterized by a (Z)-configuration as shown in Figure 1. In addition, an acyl group is present on the secondary alcohol of the glycerol. This acyl group is constituted by a saturated or unsaturated lipid chain or, in the case of platelet-activating factor

• deprotonation of solketal in DMF followed by the addition of oleyl alcohol tosylate. 9.3 was isolated after the hydrolysis in acidic conditions of the acetal protecting group. The protection of the primary alcohol required a protecting group that can be deprotected without affecting the C=C double bond of the

• with mCPBA produced the epoxide 13.3. Then, the addition of benzoic acid in the presence of acid catalysis produced an ester that was saponified to yield the diol 13.4. A three-step sequence is applied to produce compound 13.5 that features a secondary alcohol protected with a benzyl group. Then, the

Non-noble metal-catalyzed cross-dehydrogenation coupling (CDC) involving ether α-C(sp³)–H to construct C–C bonds

• Hui Yu and
• Feng Xu

Beilstein J. Org. Chem. 2023, 19, 1259–1288, doi:10.3762/bjoc.19.94

• copper is to activate the 1,3-dicarbonyl compounds through complexation that leads to a highly diastereoselective nucleophilic addition. Scheidt et al. reported an enantioselective Cu-catalyzed intramolecular cross-dehydrogenative coupling approach to substituted tetrahydropyrans with excellent yields

• oxidative olefination of simple ethers might undergo the following three successive steps: (1) the formation of an α-carbon-centered radical A from simple ethers, (2) addition of the α-carbon-centered radical to olefins generating radical B. This step is one of the classical transformations of radicals and

• ketones 94 with ethers [81]. Contrary to what was obtained for the alkylation of coumarin at the carbonyl α-position, vinyl ketone undergoes Michael addition and ether addition at the β-position of the carbonyl (Scheme 20). The reaction delivered various alkylation products in good to excellent yields

Metal catalyst-free N-allylation/alkylation of imidazole and benzimidazole with Morita–Baylis–Hillman (MBH) alcohols and acetates

• Olfa Mhasni,
• Jalloul Bouajila and
• Farhat Rezgui

Beilstein J. Org. Chem. 2023, 19, 1251–1258, doi:10.3762/bjoc.19.93

• reflux with an azeotropic distillation, was successfully carried out with no catalysts or additives, affording the corresponding N-substituted imidazole derivatives in good yields. On the other hand, in refluxing toluene or methanol, the aza-Michael addition of imidazole onto acyclic MBH alcohols was

• performed using DABCO as an additive, leading to the corresponding 1,4-adducts in 70–84% yields. Keywords: allylic substitution; aza-Michael addition; imidazole; Morita–Baylis–Hillman; Introduction Morita–Baylis–Hillman (MBH) adducts are multifunctionalized compounds having both a hydroxy moiety and a

• in the presence of imidazole (2a), as a powerful nucleophilic additive, affording, via competitive allylic nucleophilic substitution in toluene at reflux, a mixture of the corresponding N-substituted morpholine and N-substituted imidazole derivatives 6 [23]. In addition, a literature survey showed

Acetaldehyde in the Enders triple cascade reaction via acetaldehyde dimethyl acetal

• Alessandro Brusa,
• Debora Iapadre,
• Maria Edith Casacchia,
• Alessio Carioscia,
• Giuliana Giorgianni,
• Giandomenico Magagnano,
• Fabio Pesciaioli and
• Armando Carlone

Beilstein J. Org. Chem. 2023, 19, 1243–1250, doi:10.3762/bjoc.19.92

• intercepts the nitroalkene 3 in a Michael-type addition forming intermediate B. Hydrolysis regenerates catalyst 1 that can then selectively condense with the α,β-unsaturated aldehyde 4 to form chiral iminium ion intermediate C. Iminium ion C reacts with intermediate B in a further Michael-type reaction. The

• , (E)-3-chloroacrylic acid, 2,4,6-trimethyl-1,3,5-trioxane (paraldehyde) [24][27], and acetaldehyde dimethyl acetal (6) [17][18][19]. On the basis of a long-term project based on masked reagents, our group has previously demonstrated the feasibility of the addition of a masked acetaldehyde 6 to

• aldehydes other than acetaldehyde generates higher control [11]. It was previously shown that the first stereogenic center formed in the presented cascade process is formed with high control [17]. Therefore, the second carbon–carbon bond forming step, i.e., the organocatalyzed Michael addition of the

Selective construction of dispiro[indoline-3,2'-quinoline-3',3''-indoline] and dispiro[indoline-3,2'-pyrrole-3',3''-indoline] via three-component reaction

• Ziying Xiao,
• Fengshun Xu,
• Jing Sun and
• Chao-Guo Yan

Beilstein J. Org. Chem. 2023, 19, 1234–1242, doi:10.3762/bjoc.19.91

• selectively produced by using differently substituted 3-methyleneoxindoles (reaction 4 in Scheme 1). Herein, we wish to report these interesting results. Results and Discussion At first, 3-isatyl-1,4-dicarbonyl compound 1 was prepared by DBU-catalyzed Michael addition reaction of dimedone and ethyl 2-(2

• meantime, the condensation of isatin 2 with ammonium acetate gave the 3-iminoisatin intermediate A. Secondly, Michael addition of the in situ-generated carbanion of the 3-isatyl-1,4-dicarbonyl compound 1 to 3- iminoisatin A gave intermediate B. In the case of intermediate B1 with an ethoxycarbonyl group

• , the nucleophilic addition of the amino anion to the carbonyl group in the of 1,3-cyclohexanedione scaffold resulted in cyclic intermediate C. Thirdly, the elimination of water from intermediate C gave the isolated product 3. In the case of the intermediate B2 with a benzoyl group, there are two kinds

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

• , such as hydrogen atom transfer (HAT), alkene addition, and decarboxylation. At least as important has been innovation in radical functionalization methods, including radical–polar crossover (RPC), enabling these intermediates to be engaged in productive and efficient bond-forming steps. However, direct

• driven by several key features of RLT catalysis, including the ability to form diverse bonds (including C–X, C–N, and C–S), the use of simple earth abundant element catalysts, and the intrinsic compatibility of this approach with varied radical generation methods, including HAT, radical addition, and

• functionalization of alkyl radicals, with successful synthetic reactions requiring efficiency and selectivity in both of these processes and inherent compatibility between each. Radical generation has benefitted from many general mechanistic approaches, including hydrogen atom transfer (HAT) [5], alkene addition [6

Cyanothioacetamides as a synthetic platform for the synthesis of aminopyrazole derivatives

• Valeriy O. Filimonov,
• Alexandra I. Topchiy,
• Vladimir G. Ilkin,
• Tetyana V. Beryozkina and
• Vasiliy A. Bakulev

Beilstein J. Org. Chem. 2023, 19, 1191–1197, doi:10.3762/bjoc.19.87

• upon addition of hydrochloric acid. This is probably due to the protonation of the dimethylamino moiety or/and that dimethylamine hydrochloride is a better leaving group than the free base. The structures of compounds 6a–f were confirmed by 1H and 13C NMR spectroscopy and HRMS, as well as X-ray

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

• , they believed that the reaction was likely initiated by either single electron transfer between the reagents (not shown), or by electrophilic addition of the olefin onto the ylide, forming intermediate adduct 17. This was followed by formation of iodocycle 18, from which reductive elimination of

• ). In the earlier study, Koser recovered 24 and 27, and they proposed an ionic mechanism wherein the ylide acted as a nucleophile, giving 26 as the initial intermediate (Figure 7, top). To account for the differing products observed, Hadjiarapoglou instead suggested that an electrophilic addition

• iodobenzene then generated a strained, cyclopropane-fused bicycle 49 that rearranged into the isolated C–H insertion product 46a. In addition to Neiland’s disclosure of the reactions between iodonium ylides and hydrochloric acid (Scheme 1) [1][102], others have also reported that both strong acids (e.g., TsOH

Retraction: One-pot odourless synthesis of thioesters via in situ generation of thiobenzoic acids using benzoic anhydrides and thiourea

• Mohammad Abbasi and
• Reza Khalifeh

Beilstein J. Org. Chem. 2023, 19, 1170–1170, doi:10.3762/bjoc.19.85

• Mohammad Abbasi Reza Khalifeh Chemistry Department, Faculty of Sciences, Persian Gulf University, Bushehr 75169, Iran Department of Chemistry, Shiraz University of Technology, Shiraz, Iran 10.3762/bjoc.19.85 Keywords: benzoic anhydride; Michael addition; nucleophilic displacement; thioester

Two new lanostanoid glycosides isolated from a Kenyan polypore Fomitopsis carnea

• Winnie Chemutai Sum,
• Sherif S. Ebada,
• Didsanutda Gonkhom,
• Cony Decock,
• Rémy Bertrand Teponno,
• Josphat Clement Matasyoh and
• Marc Stadler

Beilstein J. Org. Chem. 2023, 19, 1161–1169, doi:10.3762/bjoc.19.84

• bioactive lanostane triterpenoids [9][10]. In addition, the edible European fungus Macrolepiota procera also produced antiproliferative and anti-inflammatory lanostanoid derivatives [11]. Furthermore, triterpenes from Tricholoma pardinum and Fomitopsis betulina (previously known as Piptoporus betulinus

• ]. Chemical investigations of F. pinicola or F. betulina revealed their cytotoxic [21][23] and antidiabetic propensities [19]. In addition, the recent review on F. officinalis, elaborated the potential use of its compounds as antibiotic leads [19]. In this study we report the isolation and structure

• methylene groups at δH 2.65/2.69 (H2-2') and δH 2.69/2.72 (H2-4') to an ester carbonyl (δC 172.4, C-1') and a carboxyl (δC 175.0, C-5'), respectively. In addition, both methylene groups together with a methyl singlet at δH 1.38 (s, H3-6') disclosed key HMBC correlations to a quaternary oxygenated carbon at

New one-pot synthesis of 4-arylpyrazolo[3,4-b]pyridin-6-ones based on 5-aminopyrazoles and azlactones

• Vladislav Yu. Shuvalov,
• Ekaterina Yu. Vlasova,
• Tatyana Yu. Zheleznova and
• Alexander S. Fisyuk

Beilstein J. Org. Chem. 2023, 19, 1155–1160, doi:10.3762/bjoc.19.83

• obtained under solvent-free conditions followed by the addition of t-BuOK in DMSO, the yield of pyrazolo[3,4-b]pyridin-6-one 4a was higher (73%, Table 1, entry 5) than when performing the reaction in a solvent (60%, Table 1, entry 6). Therefore, this procedure was used for the synthesis of compounds 4b–i

Selective and scalable oxygenation of heteroatoms using the elements of nature: air, water, and light

• Damiano Diprima,
• Hannes Gemoets,
• Stefano Bonciolini and
• Koen Van Aken

Beilstein J. Org. Chem. 2023, 19, 1146–1154, doi:10.3762/bjoc.19.82

• additional reaction pathway is proposed in which the incorporated oxygen on the heteroatoms originates from water. Furthermore, the addition of certain additives enhances productivity by affecting kinetics. The industrial potential is demonstrated by conveniently transferring the batch protocol to continuous

• of water (Table 1, entries 1 and 2), the addition of oxygen (entries 1, 5, and 6) and light in the UV-A region (entries 8 and 9) turned out to be crucial (see Supporting Information File 1, Table S2). Additives With the ultimate goal in mind to develop a safe and scalable protocol in continuous flow

• acids, an increase in reaction rate was observed. For example, when adding 1 equiv trifluoroacetic acid, a full conversion was achieved in 40 minutes instead of 60 minutes. Contrarily, the addition of a strong base substantially slowed down the reaction rate, e.g., the addition of 1 equiv NaOH resulted

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

• photon (400–700 nm; 1.8–3.1 eV). In addition, this energy is also diminished by as much as ≈25% through vibrational relaxation, internal conversion and intersystem crossing [11] and hence, many highly stabilized molecules including important feedstock molecules such as arenes, haloarenes or olefins

• radical anion or radical cation. As a semi-stable, higher energy ground-state entity, this can accumulate in sufficient concentration under the reaction conditions to absorb another photon and thereby generate a super-reducing or super-oxidizing excited state (Figure 2 left). In addition to ‘radical ion

• for reductive dehalogenations (Figure 8A), C–H arylations and olefinations of aryl halides (Figure 8B) [51]. In addition to the classical conPET mechanism involving the formation of *AQN•−, the authors also confirmed formation of the semiquinone anion AQN-H− via formal addition of a hydrogen atom (e.g

Synthesis of imidazo[4,5-e][1,3]thiazino[2,3-c][1,2,4]triazines via a base-induced rearrangement of functionalized imidazo[4,5-e]thiazolo[2,3-c][1,2,4]triazines

• Dmitry B. Vinogradov,
• Alexei N. Izmest’ev,
• Angelina N. Kravchenko,
• Yuri A. Strelenko and
• Galina A. Gazieva

Beilstein J. Org. Chem. 2023, 19, 1047–1054, doi:10.3762/bjoc.19.80

• prepare the corresponding carboxylic acids 4 using an aqueous KOH solution. Heating esters 1a,b in an aqueous solution of KOH and subsequent addition of hydrochloric acid led to the corresponding acids 4a,b as the main products. Acids 4a,b were isolated from the mixtures in 17 and 38% yield, respectively

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

• the S0 → 1CS transition [52][53][54]. In addition, the aromatic ring attached to the NI unit changing it from an electron-pulling group to an electron-pushing group, leads to a blue shift of the absorption peak of the CS and the absorbance decreases (Figure S30 in Supporting Information File 1). For

• 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

• methods (the UV–vis absorption and fluorescence emission spectra, etc.), and herein we also demonstrated that transient absorption spectra (femtosecond/nanosecond transient absorption spectra) can be used to study the TADF properties, for instance by monitoring the dark states. In addition, we show that

Copper-catalyzed N-arylation of amines with aryliodonium ylides in water

• Kasturi U. Nabar,
• Bhalchandra M. Bhanage and
• Sudam G. Dawande

Beilstein J. Org. Chem. 2023, 19, 1008–1014, doi:10.3762/bjoc.19.76

• ylide 2a proceeds efficiently in the presence of 10 mol % of CuSO4·5H2O in water as a solvent at 60 °C to provide diphenylamine (3a) with 82% yield (Table 1, entry 11). In addition, we conducted the reaction in the presence of 10 mol % of CuSO4·5H2O as a catalyst in water as a solvent at room

Five new sesquiterpenoids from agarwood of Aquilaria sinensis

• Hong Zhou,
• Xu-Yang Li,
• Hong-Bin Fang,
• He-Zhong Jiang and
• Yong-Xian Cheng

Beilstein J. Org. Chem. 2023, 19, 998–1007, doi:10.3762/bjoc.19.75

• , H-7/C-5, and H3-15/C-9 (δC 43.0) allowed us to assign another six-membered ring, as shown in Figure 2. Furthermore, the positions of a methyl group at C-10 were clarified by the HMBC correlations of H3-15/C-1, C-5, C-9, and C-10, respectively. In addition, the HMBC correlations of H-3/C-14 (δC 174.9

Synthesis of tetrahydrofuro[3,2-c]pyridines via Pictet–Spengler reaction

• Elena Y. Mendogralo and
• Maxim G. Uchuskin

Beilstein J. Org. Chem. 2023, 19, 991–997, doi:10.3762/bjoc.19.74

• with an insufficient stabilization of the generated iminium cation due to the presence of a strong electron-withdrawing nitro group (for 3n), and due to the fact that the electron deficiency of the pyridine ring is strongly manifested in an acidic media (for 3m). In addition, the disadvantages of the

• optimized reaction conditions, in addition to the desired tetrahydrofuro[3,2-c]pyridine (4h), led to the major formation of the corresponding 1,4-diketone 5h. This unexpected formation of 3-(2-oxopropyl)piperidin-4-one (5h) led us to the idea that the tandem sequence Pictet–Spengler cyclization/furan acid

• conditions, and reasonable yields are some of the attractive features of the developed method. In addition, we have also demonstrated some transformations of the products into functionalized derivatives. Examples of natural and bioactive hydrogenated furo[3,2-c]pyridines. The described approaches to

The unique reactivity of 5,6-unsubstituted 1,4-dihydropyridine in the Huisgen 1,4-diploar cycloaddition and formal [2 + 2] cycloaddition

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

Beilstein J. Org. Chem. 2023, 19, 982–990, doi:10.3762/bjoc.19.73

• ]. The well-known Huisgen 1,4-dipoles have a special kind of zwitterionic intermediates and are usually prepared by a nucleophilic addition of pyridine, quinoline, isoquinoline and other aza-arenes to electron-deficient alkynes [4][5][6][7][8]. The reactive Huisgen 1,4-dipoles have been widely employed

• -configured. For explaining the formation of the various cyclic compounds, a plausible reaction mechanism was proposed on the base of the previously reported works [41][42][43][44] and the present experiments (Scheme 2). Initially, the nucleophilic addition of isoquinoline to dimethyl acetylenedicarboxylate

• gives the well-known Huisgen 1,4-dipole A. Secondly, Michael addition of the 1,4-dipole A to 5,6-unsubstituted 1,4-dihydropyridine gives the adduct intermediate B. At last, the intramolecular coupling of the negative and the positive charges in intermediate B directly affords isoquinolino[1,2-f][1,6

Aromatic C–H bond functionalization through organocatalyzed asymmetric intermolecular aza-Friedel–Crafts reaction: a recent update

• Anup Biswas

Beilstein J. Org. Chem. 2023, 19, 956–981, doi:10.3762/bjoc.19.72

• –Crafts reaction has also been explored under the influence of organocatalysis. However, here organocatalysts act as Brønsted acids which form noncovalent interactions (H-bonding) with the imine nitrogen to enhance the electrophilicity of the imine component. In addition, by selecting suitable imine

• enantioselective aza-Friedel–Crafts addition. In the first step, the DDQ-promoted oxidation of 3-indolinonecarboxylate 22 generated indolenines that performed as the potential electrophiles towards indoles 4. The chiral catalyst effectively assembled the reacting partners in a chiral transition state through H

• activation of the reaction components through H-bonding engagement with free hydroxy groups of the catalysts also favoring stereoselective addition (see structure 28 in Scheme 8a) [32]. Two years later, the same research group utilized the C1-symmetric catalyst P10 for the functionalization of the C3–H bond

Clauson–Kaas pyrrole synthesis using diverse catalysts: a transition from conventional to greener approach

• Dileep Kumar Singh and
• Rajesh Kumar

Beilstein J. Org. Chem. 2023, 19, 928–955, doi:10.3762/bjoc.19.71

• with electron‐donating groups (i.e., OMe, Me) reacted much faster than aniline and furnished the pyrroles in excellent yields. In addition, the reaction of more sterically hindered aniline with 2,5-dimethoxytetrahydrofuran gave moderate yields and less sterically hindered aniline gave good yields. This

• reactivity of the aromatic amine depends on the electron density of the amino compounds. In addition, the authors also performed the reaction of aliphatic amines with 2,5-DMTHF (2), and found that aliphatic amines are inert in the presence of MgI2 etherate. The proposed mechanism shown in Scheme 9b suggests

• addition, this procedure has many other advantages such as simple experimental work-up, easy availability of reagents, high to excellent yields, and environmental friendliness of the catalyst. To optimize the reaction conditions, the authors screened different solvents, catalyst loading, and temperature

Photoredox catalysis enabling decarboxylative radical cyclization of γ,γ-dimethylallyltryptophan (DMAT) derivatives: formal synthesis of 6,7-secoagroclavine

• Alessio Regni,
• Francesca Bartoccini and
• Giovanni Piersanti

Beilstein J. Org. Chem. 2023, 19, 918–927, doi:10.3762/bjoc.19.70

• accomplish by more conventional procedures, enables the synthesis of ergot alkaloid precursors. In addition, this work describes a mild, environmentally friendly method to activate, reductively and oxidatively, natural carboxylic acids for decarboxylative C–C bond formation by exploiting the same

• carboxylate anion and/or reduction of the corresponding N-hydroxyphthalimide- (NHPI)-derived redox-active ester, although it destroys their stereochemical information [46][47][48][49][50][51]. In addition, the side-chains of aromatic amino acids (mainly electron-rich tryptophan and tyrosine) can be

• )PF6 (E1/2*III/II = +1.21 V, E1/2III/II = −1.37; E1/2IV/*III = −0.89, E1/2 IV/III = +1.69 V) [74] would permit efficient radical generation and C(sp3)–C(sp3) bond formation either by challenging selective radical–radical cross-coupling or by radical addition to a π-bond, enabling a rare example of

Intermediates and shunt products of massiliachelin biosynthesis in Massilia sp. NR 4-1

• Till Steinmetz,
• Blaise Kimbadi Lombe and
• Markus Nett

Beilstein J. Org. Chem. 2023, 19, 909–917, doi:10.3762/bjoc.19.69

• ). Although the architecture of the corresponding locus suggested an involvement in the production of a lipopeptide siderophore, the gene cluster could not be unequivocally associated with a known compound. The assumption that Massilia sp. NR 4-1 synthesizes iron-chelating molecules in addition to

• volume of 100 mL, hence yielding the blue CAS assay solution. To perform the assay, 1 mL of the CAS assay solution was pipetted into a cuvette followed by the addition of 0.2 mL of the substance to be tested. A color change from blue to yellow indicated the presence of metal-chelating molecules. Filter

Synthesis of aliphatic nitriles from cyclobutanone oxime mediated by sulfuryl fluoride (SO₂F₂)

• Xian-Lin Chen and
• Hua-Li Qin

Beilstein J. Org. Chem. 2023, 19, 901–908, doi:10.3762/bjoc.19.68

• ], Liu [35], and Yang [36] achieved similar transformations through visible-light photocatalysis. In addition, Guo [37][38] improved the protocol by using low-cost nickel and iron catalysts. However, most of these advancements mainly relied on the excellent redox potential manipulation of cyclic oxime

• ). Furthermore, the desired products were not even obtained when the starting materials were connected to extra strong electron-withdrawing groups (such as a nitro group) on their aromatic rings. In addition, a series of cyclobutanone oxime derivatives were also smoothly transformed into the corresponding

• 1a and facilitate the ultimate addition process. The selectivity of bases for different processes may attract significant attention for further applications. In order to understand the mechanism of the aforementioned transformation, some experimental investigations were performed as described in

First synthesis of acylated nitrocyclopropanes

• Kento Iwai,
• Rikiya Kamidate,
• Khimiya Wada,
• Haruyasu Asahara and
• Nagatoshi Nishiwaki

Beilstein J. Org. Chem. 2023, 19, 892–900, doi:10.3762/bjoc.19.67

• bulkier. The obtained nitrocyclopropane was transformed into furan upon treatment with tin(II) chloride via a ring-opening/ring-closure process. Keywords: acetoxyiodine; conjugate addition; dihydrofuran; nitroalkene; nitrocyclopropane; Introduction 3-Arylated 2-nitrocyclopropane-1,1-dicarbonylic acid

• esters 1a have recently attracted considerable attention from synthetic organic chemists. In addition to their polyfunctionality, their ring strain and electron deficiency lead to a wide variety of reactivities. Based on their electron-deficient nature, these compounds have been used as substrates in the

• ). These structural features enable the construction of a five-membered ring upon treatment with alkenes [9], diazo compounds (reaction g) [10], and nitriles [11]. Several approaches are available for the synthesis of cyclopropanedicarboxylates 1a, which consist of three steps: 1) conjugate addition, 2