Advances in the use of metal-free tetrapyrrolic macrocycles as catalysts

• Mandeep K. Chahal

Beilstein J. Org. Chem. 2024, 20, 3085–3112, doi:10.3762/bjoc.20.257

• -workers reported using metal-free planar H2TPP (18) as a photocatalyst for the photoredox-α-alkylation of aldehydes with ethyl diazoacetate [91]. This reaction achieved an impressive product yield up to 84%. Control experiments showed that omitting any one of the reaction components – such as the

• suggested that the reaction of the porphyrin catalyst with the enamine and ethyl diazoacetate (EDA) played a crucial role in these α-alkylation reactions. This work demonstrated a dual catalytic system where porphyrin functioned as both a photoredox catalyst and a photosensitizer. Later, the same group used

• studies were focused on using these porphyrins as photooxidants in the red light-induced α-alkylation of aldehyde with ethyl diazoacetate. The reported reaction proceeds smoothly, giving 75% and 70% yields for macrocycles 18 and 78, respectively (Figure 17a). Irradiation of porphyrin photocatalysts by red

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

• started our studies with the palladium-catalyzed MCR of ethyl diazoacetate (1a), 1,3-butadiene (2a), and 1-phenylpiperazine (3a) in the presence of 5 mol % Pd(OAc)2 and 10 mol % Xantphos as ligand. To our delight, after irradiation with blue LED light in dimethylformamide (DMF) for 12 h at room

• , hydride shift process, and photoinduced homolytic cleavage of the C–Pd bond, furnishing hybrid α-ester alkylpalladium radical I. In path b, upon irradiation with blue light, photoexcited Pd(0)Ln* reduces ethyl diazoacetate (1a) to Pd-radical species I by a proton-coupled electron transfer (PCET) process

Gold-catalyzed ethylene cyclopropanation

• Silvia G. Rull,
• Andrea Olmos and
• Pedro J. Pérez

Beilstein J. Org. Chem. 2019, 15, 67–71, doi:10.3762/bjoc.15.7

• directly converted into ethyl 1-cyclopropylcarboxylate upon reaction with ethyl diazoacetate (N2CHCO2Et, EDA) in the presence of catalytic amounts of IPrAuCl/NaBArF4 (IPr = 1,3-bis(2,6-diisopropylphenyl)imidazole-2-ylidene; BArF4 = tetrakis(3,5-bis(trifluoromethyl)phenyl)borate). Keywords: carbene

• transfer; cyclopropane; cyclopropylcarboxylate; ethylene cyclopropanation; ethyl diazoacetate; gold catalysis; Introduction Nowadays the olefin cyclopropanation through metal-catalyzed carbene transfer starting from diazo compounds to give olefins constitutes a well-developed tool (Scheme 1a), with an

• copolymerization of ethylene and ethyl diazoacetate with rhodium-based catalysts (Scheme 2a). Ethyl cyclopropanecarboxylate has been prepared in several ways, alternative to the direct carbene addition to ethylene (Scheme 2b): ring contraction of 2-halocyclobutanone [5], cyclization of alkyl 4-halobutanoates [6

The chemistry and biology of mycolactones

• Matthias Gehringer and
• Karl-Heinz Altmann

Beilstein J. Org. Chem. 2017, 13, 1596–1660, doi:10.3762/bjoc.13.159

Catalytic Wittig and aza-Wittig reactions

• Zhiqi Lao and
• Patrick H. Toy

Beilstein J. Org. Chem. 2016, 12, 2577–2587, doi:10.3762/bjoc.12.253

• )porphyrinate), and ethyl diazoacetate (11) to generate arsonium ylide 12 for use in biphasic catalytic Wittig-type reactions (Scheme 3) [11]. In these reactions sodium hydrosulfite replaced triphenylphosphite as the reducing reagent to convert the byproduct Ph3As=O (13) back into 9 in the aqueous phase of the

• -catalysts. Prototypical Wittig reaction involving in situ phosphonium salt and phosphonium ylide formation. Bu3As-catalyzed Wittig-type reactions. Ph3As-catalyzed Wittig-type reactions using Fe(TCP)Cl and ethyl diazoacetate for arsonium ylide generation. Bu2Te-catalyzed Wittig-type reactions. Polymer

Rearrangements of organic peroxides and related processes

• Ivan A. Yaremenko,
• Vera A. Vil’,
• Dmitry V. Demchuk and
• Alexander O. Terent’ev

Beilstein J. Org. Chem. 2016, 12, 1647–1748, doi:10.3762/bjoc.12.162

On the cause of low thermal stability of ethyl halodiazoacetates

• Magnus Mortén,
• Martin Hennum and
• Tore Bonge-Hansen

Beilstein J. Org. Chem. 2016, 12, 1590–1597, doi:10.3762/bjoc.12.155

• half-lives. The experimental results are supported by DFT calculations, and we provide a possible explanation for the reduced thermal stability of ethyl halodiazoacetates compared to ethyl diazoacetate and for the relative decomposition rates between the chloro, bromo and iodo analogs. We have also

• organic chemists ever since Theodor Curtius synthesized ethyl diazoacetate (EDA, 1) for the first time in 1883 [1]. Even today, after more than a century of research, diazo compounds still play an important role in state-of-the-art organic chemistry in areas such as for example C–H functionalization [2

• relative to their aliphatic counterparts is explained by the electron-acceptor character of the carbonyl group. The presence of one or two ester groups α to the diazo functionality leads to increased stability so that elevated temperatures are usually needed in order to induce thermal decomposition. Ethyl

Evidencing an inner-sphere mechanism for NHC-Au(I)-catalyzed carbene-transfer reactions from ethyl diazoacetate

• Manuel R. Fructos,
• Juan Urbano,
• M. Mar Díaz-Requejo and
• Pedro J. Pérez

Beilstein J. Org. Chem. 2015, 11, 2254–2260, doi:10.3762/bjoc.11.245

• Abstract Kinetic experiments based on the measurement of nitrogen evolution in the reaction of ethyl diazoacetate (N2CHCO2Et, EDA) and styrene or methanol catalyzed by the [IPrAu]+ core (IPr = 1,3-bis(diisopropylphenyl)imidazole-2-ylidene) have provided evidence that the transfer of the carbene group

• extended to many of the reported catalytic systems involving Au(I) complexes. Results and Discussion The probe reactions As mentioned above, we have already described the potential of the system IPrAuCl + NaBArF4 to promote the catalytic decomposition of ethyl diazoacetate (N2CHCO2Et, EDA) and

• carbene and the substrate. This approach would also explain the lack of formation of the olefins derived from carbene coupling with this Au(I)-based system. Conclusion The experimental results obtained from the measurement of N2 evolution in [IPrAu]+-catalyzed carbene transfer from ethyl diazoacetate have

Synthesis of quinoline-3-carboxylates by a Rh(II)-catalyzed cyclopropanation-ring expansion reaction of indoles with halodiazoacetates

• Magnus Mortén,
• Martin Hennum and
• Tore Bonge-Hansen

Beilstein J. Org. Chem. 2015, 11, 1944–1949, doi:10.3762/bjoc.11.210

• rapidly (<1min reaction time) from ethyl diazoacetate (EDA), DBU and an N-halo succinimide (NXS) of choice according to Scheme 1. In this letter we report our results from the reactions between a series of indoles with halodiazoacetates. Results and Discussion We initiated our study by investigating the

Stereocontrolled synthesis of 5-azaspiro[2.3]hexane derivatives as conformationally “frozen” analogues of L-glutamic acid

• Beatrice Bechi,
• David Amantini,
• Cristina Tintori,
• Maurizio Botta and
• Romano di Fabio

Beilstein J. Org. Chem. 2014, 10, 1114–1120, doi:10.3762/bjoc.10.110

• exploration of the reactivity of the terminal olefin towards the key cyclopropanation step performed in the presence of ethyl diazoacetate and Rh2(OAc)4 (rhodium acetate dimer). The reaction was carefully studied in different solvents (i.e., CH2Cl2, DCE, toluene) and with variable amounts of both ethyl

• diazoacetate and Rh2(OAc)4. In particular, encouraging results were obtained when the reaction was performed in CH2Cl2 in the presence of 1 equivalent of ethyl diazoacetate added to the reaction mixture by a syringe pump over 10 h, heated under reflux, and in the presence of a catalytic amount of Rh2(OAc)4

• . Under these conditions target compound 20 was obtained in poor yield (12%) as a mixture of diastereoisomers inseparable by flash chromatography. Then, the use of an excess of ethyl diazoacetate (8 equivalents) led to an increased reaction yield of up to 51%. Finally, an optimization study on both the

Preparation of phosphines through C–P bond formation

• Iris Wauters,
• Wouter Debrouwer and
• Christian V. Stevens

Beilstein J. Org. Chem. 2014, 10, 1064–1096, doi:10.3762/bjoc.10.106

• oxidation, the perfluoroalkyl-substituted phosphine oxides 32 were obtained in low to moderate yields (15–51%) although full conversion was observed. The byproduct formed was reduced perfluoroalkane HCnF2n+1. Ethyl diazoacetate (33) was reacted with the secondary phosphine borane 13a in the presence of a

Ethyl diazoacetate synthesis in flow

• Mariëlle M. E. Delville,
• Jan C. M. van Hest and
• Floris P. J. T. Rutjes

Beilstein J. Org. Chem. 2013, 9, 1813–1818, doi:10.3762/bjoc.9.211

• Marielle M. E. Delville Jan C. M. van Hest Floris P. J. T. Rutjes Radboud University Nijmegen, Institute for Molecules and Materials, Heyendaalseweg 135, 6525 AJ Nijmegen, the Netherlands 10.3762/bjoc.9.211 Abstract Ethyl diazoacetate is a versatile compound in organic chemistry and frequently

• quantities. Ethyl diazoacetate was prepared in a biphasic mixture comprising an aqueous solution of glycine ethyl ester, sodium nitrite and dichloromethane. Optimization of the reaction was focused on decreasing the residence time with the smallest amount of sodium nitrite possible. With these boundary

• conditions, a production yield of 20 g EDA day−1 was achieved using a microreactor with an internal volume of 100 μL. Straightforward scale-up or scale-out of microreactor technology renders this method viable for industrial application. Keywords: diazo compounds; diazotization; ethyl diazoacetate (EDA

α-Bromodiazoacetamides – a new class of diazo compounds for catalyst-free, ambient temperature intramolecular C–H insertion reactions

• Åsmund Kaupang and
• Tore Bonge-Hansen

Beilstein J. Org. Chem. 2013, 9, 1407–1413, doi:10.3762/bjoc.9.157

• ][27][28][29][30], as well as carbon, e.g., in aldol reactions with aldehydes [31][32], ketones [33][34] and imines [35][36]. The first syntheses of α-halodiazoacetic esters, reported in the late 1960s, employed electrophilic diazoalkane substitution; the mercury or silver salts of ethyl diazoacetate

Synthesis of 2,6-disubstituted tetrahydroazulene derivatives

• Zakir Hussain,
• Henning Hopf,
• Khurshid Ayub and
• S. Holger Eichhorn

Beilstein J. Org. Chem. 2012, 8, 693–698, doi:10.3762/bjoc.8.77

• '-carbonyldiimidazole, tert-butyl alcohol and DBU to afford ester 3 in quantitative yield. The ester 3 was then subjected to carbene addition by treatment with ethyl diazoacetate in the presence of a copper catalyst [17] in THF under reflux. The carbene adduct 4 was obtained as the major product, as a colorless oil in

• higher yields when the length of time used for the addition of the ethyl diazoacetate was extended, which was again similar to our earlier investigations [10]. The formation of only one major isomer (4) in this case could be due to the greater steric hindrance for carbene addition to the inner carbon

Intramolecular carbenoid ylide forming reactions of 2-diazo-3-keto-4-phthalimidocarboxylic esters derived from methionine and cysteine

• Marc Enßle,
• Stefan Buck,
• Roland Werz and
• Gerhard Maas

Beilstein J. Org. Chem. 2012, 8, 433–440, doi:10.3762/bjoc.8.49

• analogously; it should be noted that different approaches were taken to obtain the methyl ester analogue of 11b and other similar sulfur-containing α-diazo-β-ketoesters [14][15][16]. We found that diazoester 8a can also be prepared by acylation of ethyl diazoacetate (two equivalents, one equivalent serving to

When cyclopropenes meet gold catalysts

• Frédéric Miege,
• Christophe Meyer and
• Janine Cossy

Beilstein J. Org. Chem. 2011, 7, 717–734, doi:10.3762/bjoc.7.82

• ethyl diazoacetate on bulk gold powder were also studied, but mixtures of self- and cross-coupling products were invariably obtained with negligible selectivity. Interestingly, the authors investigated the intermolecular cyclopropanation of styrene by the surface bound gold carbene generated from

Gold-catalyzed naphthalene functionalization

• Pedro J. Pérez,
• M. Mar Díaz-Requejo and
• Iván Rivilla

Beilstein J. Org. Chem. 2011, 7, 653–657, doi:10.3762/bjoc.7.77

• unsaturated substrates, including aromatics [3]. Thus, the reaction of ethyl diazoacetate (EDA) with benzene in the presence of such catalysts at room temperature exclusively affords the cycloheptatriene product in quantitative yields. The reaction, always referred to the intermolecular version, was later

• derivatives, formed by the cyclopropanation of one of the double bonds of the naphthalene ring. Later, Müller and co-workers [9] showed the effect of a series of Rh2(L-L)4 in the same transformation but with ethyl diazoacetate as the carbene source. A mixture of the products (2a–d) arising from

• found that the gold complex IPrAuCl (1b) (IPr = 1,3-bis(diisopropylphenyl)imidazol-2-ylidene) in the presence of one equiv of NaBAr'4 (Ar' = 3,5-bis(trifluoromethyl)phenyl) induced the functionalization of benzene with ethyl diazoacetate to give a mixture of a cycloheptatriene and ethyl 2-phenylacetate

Sequential Au(I)-catalyzed reaction of water with o-acetylenyl-substituted phenyldiazoacetates

• Lei Zhou,
• Yizhou Liu,
• Yan Zhang and
• Jianbo Wang

Beilstein J. Org. Chem. 2011, 7, 631–637, doi:10.3762/bjoc.7.74

• , Díaz-Requejo, Nolan, Pérez and co-workers reported the first example of carbene transfer from ethyl diazoacetate (EDA) using (IPr)AuCl. The subsequent generation of a gold carbene was followed by insertion into a phenyl C–H bond, an O–H bond, or an N–H bond [6]. Similar reactions were also reported by

• Dias and co-workers with a gold(I) ethylene complex [7]. Although the scope of those studies was limited to ethyl diazoacetate, the examples therein demonstrated that gold complexes can be used as efficient catalysts in carbene transfer reactions with diazo compounds. On the other hand, the development

Synthesis of chiral mono(N-heterocyclic carbene) palladium and gold complexes with a 1,1'-biphenyl scaffold and their applications in catalysis

• Lian-jun Liu,
• Feijun Wang,
• Wenfeng Wang,
• Mei-xin Zhao and
• Min Shi

Beilstein J. Org. Chem. 2011, 7, 555–564, doi:10.3762/bjoc.7.64

• allylic acetates [75][76], carbene-transfer reactions from ethyl diazoacetate [77], formation of conjugated enones and enals [78], regio- and stereoselective synthesis of fluoroalkenes [79], and so on [80][81][82][83][84][85]. However, reports on NHC–Au catalyzed asymmetric reactions are rare [86]. The

Bis(oxazolines) based on glycopyranosides – steric, configurational and conformational influences on stereoselectivity

• Tobias Minuth and
• Mike M. K. Boysen

Beilstein J. Org. Chem. 2010, 6, No. 23, doi:10.3762/bjoc.6.23

• ligands were subsequently employed in the asymmetric cyclopropanation [22][23] of styrene (4) with ethyl diazoacetate (5). Our results revealed a strong dependence of the enantioselectivity on both the steric bulk and electronic nature of the O-substituents in ligands 2a–c and 3a–f. Furthermore, the

Sordarin, an antifungal agent with a unique mode of action

• Huan Liang

Beilstein J. Org. Chem. 2008, 4, No. 31, doi:10.3762/bjoc.4.31

• (Scheme 9). The latter was directly converted to a β-ketoester by reaction with ethyl diazoacetate in the presence of SnCl2. A final Knoevenagel cyclization afforded substance 45. The enantioselective synthesis implemented an improved procedure that relied on alkylation of the metallohydrazone of 43 with