N-Boc-α-diazo glutarimide as efficient reagent for assembling N-heterocycle-glutarimide diads via Rh(II)-catalyzed N–H insertion reaction

• Grigory Kantin,
• Pavel Golubev,
• Alexander Sapegin,
• Alexander Bunev and
• Dmitry Dar’in

Beilstein J. Org. Chem. 2023, 19, 1841–1848, doi:10.3762/bjoc.19.136

• , including both aromatic and saturated NH-substrates. This yields structures that are appealing for generating cereblon ubiquitin-ligase ligands and for potential use in crafting PROTAC molecules. Keywords: CRBN ligands; diazocarbonyl compounds; N–H insertion reaction; N-heterocycles; Rh(II)-catalysis

• lactams). The second approach, which asserts its universality, frequently displays inadequate yield of target compounds. As such, the endeavour to discover novel approaches for synthesizing N-heterocycle-glutarimide ensembles of type 1 persists as imperative. Aliphatic diazocarbonyl reagents are widely

• characterized by high regioselectivity. We obtained tetrazol-2-yl glutarimides 6p and 6q in moderate yields. Alternative regioisomers (tetrazol-1-yl glutarimides) were observed only in trace amounts (according to NMR data). It should be noted that in this work the insertion of the diazocarbonyl reagent into the

Unusual highly diastereoselective Rh(II)-catalyzed dimerization of 3-diazo-2-arylidenesuccinimides provides access to a new dibenzazulene scaffold

• Anastasia Vepreva,
• Alexander S. Bunev,
• Andrey Yu. Kudinov,
• Grigory Kantin,
• Mikhail Krasavin and
• Dmitry Dar’in

Beilstein J. Org. Chem. 2022, 18, 533–538, doi:10.3762/bjoc.18.55

• vinyl-substituted diazocarbonyl compounds with an exclusively (E)-configured double bond which positions the aryl substituent and the diazo group in close proximity. The reactivity of DAS is twofold: on the one hand, these compounds undergo reactions which are typical for diazocarbonyl compounds, on the

• diazocarbonyl compounds [5]. The close spatial arrangement of the conjugate aryl fragment and the diazo group in the DAS molecule favors both intramolecular and intermolecular cyclizations involving the arylidene group. Thus, under catalytic decomposition, DAS containing a 2-pyridyl or 2-hydroxyaryl substituent

• impurities. In one case, azine 4k was isolated in pure form and characterized. It should be noted that such azines are typically observed as byproducts in Rh(II)-catalyzed reactions of diazocarbonyl compounds [11][12][13][14]. The introduction of a strong donor substituent (MeO) in position 4 of the

1,2,3-Triazoles as leaving groups: S_NAr reactions of 2,6-bistriazolylpurines with O- and C-nucleophiles

• Dace Cīrule,
• Irina Novosjolova,
• Ērika Bizdēna and
• Māris Turks

Beilstein J. Org. Chem. 2021, 17, 410–419, doi:10.3762/bjoc.17.37

• -halopurines [41]. O-Alkylation of guanosine and inosine with Cu(I)-stabilized carbenes derived form α-diazocarbonyl compounds is also known [42]. Alkylation of 6-oxopurine derivatives under Mitsunobu conditions which usually proceeds with O-regioselectivity are mostly described for guanine derivatives [43][44

Copper-based fluorinated reagents for the synthesis of CF₂R-containing molecules (R ≠ F)

• Louise Ruyet and
• Tatiana Besset

Beilstein J. Org. Chem. 2020, 16, 1051–1065, doi:10.3762/bjoc.16.92

• co-workers also reported the reaction of the CuCF2PO(OEt)2 reagent with α-diazocarbonyl derivatives. Depending on the copper salt used for the generation of the copper reagent, the reaction with α-diazocarbonyl derivatives provided either the α-fluorovinylphosphonate, in a stereoselective fashion, or

Recent advances in Cu-catalyzed C(sp³)–Si and C(sp³)–B bond formation

• Balaram S. Takale,
• Ruchita R. Thakore,
• Elham Etemadi-Davan and
• Bruce H. Lipshutz

Beilstein J. Org. Chem. 2020, 16, 691–737, doi:10.3762/bjoc.16.67

Preparation and in situ use of unstable N-alkyl α-diazo-γ-butyrolactams in Rh^II-catalyzed X–H insertion reactions

• Maria Eremeyeva,
• Daniil Zhukovsky,
• Dmitry Dar’in and
• Mikhail Krasavin

Beilstein J. Org. Chem. 2020, 16, 607–610, doi:10.3762/bjoc.16.55

• , the reactions tended to yield enamine adducts. Keywords: in situ reactions; N-alkyl 2-pyrrolidones; RhII-catalyzed insertion reactions; stability of diazo compounds; Introduction Recently, we described the first synthesis and subsequent transformations of a rare type of cyclic α-diazocarbonyl

• -α-diazo-γ-butyrolactams 4 did not undergo these reactions typical of α-diazocarbonyl compounds, as they rapidly dimerized to give bishydrazones 5 (Figure 1). The instability of N-alkyl-α-diazo-γ-butyrolactams 4 compared to the N-aryl counterparts 1, was most likely related to the reduced electron

• reaction of cyclopropylamine with N-phenyl-α-diazo-2-pyrrolidone [2]) can be rationalized, as proposed previously [2], either by the oxidation of diazolactam 6c to a respective ketone (a process described in the literature for other α-diazocarbonyl compounds [6]), followed by a nucleophilic attack of

Novel photochemical reactions of carbocyclic diazodiketones without elimination of nitrogen – a suitable way to N-hydrazonation of C–H-bonds

• Liudmila L. Rodina,
• Xenia V. Azarova,
• Jury J. Medvedev,
• Dmitrij V. Semenok and
• Valerij A. Nikolaev

Beilstein J. Org. Chem. 2018, 14, 2250–2258, doi:10.3762/bjoc.14.200

• with up to 90–97% yield. Keywords: C–H insertion; diazo compounds; excited state; photochemistry; Wolff rearrangement; Introduction Photochemical reactions of diazocarbonyl compounds are well-known transformations in the synthesis of the diversified acyclic, carbo- and heterocyclic structures [1][2

• ][3][4][5]. A direct irradiation of diazo compounds by UV light usually gives rise to nitrogen elimination and generation of carbenes [6][7][8][9][10] or ketenes [11][12][13][14][15][16][17][18] and their ensuing transformations. On the other hand, photochemical reactions of diazocarbonyl compounds

Continuous multistep synthesis of 2-(azidomethyl)oxazoles

• Thaís A. Rossa,
• Nícolas S. Suveges,
• Marcus M. Sá,
• David Cantillo and
• C. Oliver Kappe

Beilstein J. Org. Chem. 2018, 14, 506–514, doi:10.3762/bjoc.14.36

• preparation of oxazoles described in the literature. These include ring-closure reactions of diazocarbonyl compounds with amides or nitriles [16], α-haloketones and amides [17][18][19], cyanohydrins and aldehydes (Fischer synthesis) [20][21], or oxidative additions of α-methylene ketones to nitriles [22][23

Rh(II)-mediated domino [4 + 1]-annulation of α-cyanothioacetamides using diazoesters: A new entry for the synthesis of multisubstituted thiophenes

• Jury J. Medvedev,
• Ilya V. Efimov,
• Yuri M. Shafran,
• Vitaliy V. Suslonov,
• Vasiliy A. Bakulev and
• Valerij A. Nikolaev

Beilstein J. Org. Chem. 2017, 13, 2569–2576, doi:10.3762/bjoc.13.253

• reactions; thiophenes; Introduction In recent years the diversified reactivity of metal carbenes, catalytically generated from diazocarbonyl compounds, has found wide application in organic synthesis [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16]. A particular interest was attracted recently to

• the same molecule. The main objective of our current research was to study Rh(II)-catalyzed reactions of diazocarbonyl compounds with α-cyanothioacetamides, bearing both thioamide and cyano groups in their structure. Based on the known literature findings [36][37][38] one might expect that a catalytic

• reaction of diazocarbonyl compounds with α-cyanothioacetamides would first of all affect the electron-rich sulfur atom of the C=S group, leading to the generation of intermediate thiocarbonyl ylides, which would further react intramolecularly with the cyano group to produce a heterocyclic structure. One

Unusual reactions of diazocarbonyl compounds with α,β-unsaturated δ-amino esters: Rh(II)-catalyzed Wolff rearrangement and oxidative cleavage of N–H-insertion products

• Valerij A. Nikolaev,
• Jury J. Medvedev,
• Olesia S. Galkina,
• Ksenia V. Azarova and
• Christoph Schneider

Beilstein J. Org. Chem. 2016, 12, 1904–1910, doi:10.3762/bjoc.12.180

• ; transition-metal-catalyzed reactions; Wolff rearrangement; Introduction Transition-metal-catalyzed reactions of diazocarbonyl compounds (DCC) with different organic substrates comprise a powerful tool of organic synthesis [1][2][3][4][5][6][7][8]. Of prime importance was found to be the ability of reactive

• these processes. Herein we present the main results of this study. Diazocarbonyl compounds of three classes with dissimilar structures and usually different reactivity were tested in our current research: aroyldiazomethanes 2a–c, diazoketoesters 3a,b and diazodiketones – by the example of

• other reaction processes were observed – the Wolff rearrangement and the assumed oxidative cleavage of the initial reaction products. Several examples of Rh-catalyzed reactions of diazocarbonyl compounds with N–H-substrates, which are accompanied by the Wolff rearrangement with formation of

On the strong difference in reactivity of acyclic and cyclic diazodiketones with thioketones: experimental results and quantum-chemical interpretation

• Andrey S. Mereshchenko,
• Alexey V. Ivanov,
• Viktor I. Baranovskii,
• Grzegorz Mloston,
• Ludmila L. Rodina and
• Valerij A. Nikolaev

Beilstein J. Org. Chem. 2015, 11, 504–513, doi:10.3762/bjoc.11.57

• stage of the cycloaddition process. Keywords: diazocarbonyl compounds; 1,3-dipolar cycloaddition; 1,3-oxathioles; thiiranes; thiocarbonyl ylides; thioketones; Introduction Dipolar cycloadditions of diazo compounds have been of great interest for a long time as they provide a means for the preparation

• of a wide variety of nitrogen containing heterocyclic compounds [1][2][3][4][5]. These reactions are generally known for diazoalkanes and 2-diazocarbonyl compounds, whereas similar processes with 2-diazo-1,3-dicarbonyl compounds (DDC) are far less common [6][7][8][9][10], and reported literature data

Azirinium ylides from α-diazoketones and 2H-azirines on the route to 2H-1,4-oxazines: three-membered ring opening vs 1,5-cyclization

• Nikolai V. Rostovskii,
• Mikhail S. Novikov,
• Alexander F. Khlebnikov,
• Galina L. Starova and
• Margarita S. Avdontseva

Beilstein J. Org. Chem. 2015, 11, 302–312, doi:10.3762/bjoc.11.35

• , rhodium carbenoids derived from α-diazocarbonyl compounds transform 2H-azirines 1 to azirinium ylides 5 (Scheme 1) which undergo facile N–C2 bond cleavage to give 2-azabuta-1,3-dienes 3. Recently we showed that the use of α-diazo-β-ketoesters 2 in these reactions, which are finished by 1,6-cyclization of

Less reactive dipoles of diazodicarbonyl compounds in reaction with cycloaliphatic thioketones – First evidence for the 1,3-oxathiole–thiocarbonyl ylide interconversion

• Valerij A. Nikolaev,
• Alexey V. Ivanov,
• Ludmila L. Rodina and
• Grzegorz Mlostoń

Beilstein J. Org. Chem. 2013, 9, 2751–2761, doi:10.3762/bjoc.9.309

• -thioxocyclobutan-1-one (1a) and adamantanethione (1b), were found to be less reactive than aromatic thiobenzophenone. However, they are reactive enough to enter reactions with most of the studied diazocarbonyl compounds already at room temperature or upon heating to 80 °C. Experimental General information: 1H and

• ; arbitrary numbering of atoms). Energy profile for the transformation of 1,3-oxathiole 3e to alkene 5e. Relative free energies (kcal·mol−1, 298 K) computed at the DFT PBE1PBE/6-31G(d) level. Reaction of diazocarbonyl compounds 2a,c,e with adamantane-2-thione (1b). Three possible pathways A, B and C for the

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

• variety of reactions e.g. cyclopropanation, X–H insertion, cycloaddition and ylide formation [13][15], and more recently, in the synthesis of valuable compound classes such as β-keto esters [16] and β-hydroxy-α-diazocarbonyl compounds [17], we aimed to develop an inherently safe continuous-flow 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

• cyclic amide side chains. Keywords: α-halo-β-lactam; diazo; halocarbonylcarbene; halogenation; thermolysis; Introduction Diazocarbonyl compounds are popular precursors for carbonylcarbenes and -carbenoids, the synthetic utility of which is thoroughly established through their successful employment in

• thermolysis of an α-bromodiazoketone was successfully employed in an intramolecular cyclopropanation reaction [62]. Historically, the thermolysis of diazocarbonyl compounds has been carried out under reflux [63][64][65][66], although examples of low temperature and ambient temperature thermolysis can be found

• in the case of more labile diazo compounds [14][22][23][67]. Recent examples of thermolyses of diazocarbonyl compounds, include the preparation of arylcyclopropanes (cyclopropanation) and α-arylamino esters (N–H insertion) by thermolysis of aryldiazoacetates in trifluorotoluene under reflux [68][69

Parallel and four-step synthesis of natural-product-inspired scaffolds through modular assembly and divergent cyclization

• Hiroki Oguri,
• Haruki Mizoguchi,
• Hideaki Oikawa,
• Aki Ishiyama,
• Masato Iwatsuki,
• Kazuhiko Otoguro and
• Satoshi Ōmura

Beilstein J. Org. Chem. 2012, 8, 930–940, doi:10.3762/bjoc.8.105

• of 15, isonitrile 21, indole-3-carboxylic acid derivative 58 and aldehyde 59 produced a 1:1 diastereomeric mixture of the dipeptidyl intermediate. Stepwise installation of the α-diazocarbonyl group produced 62 in good yield. The cyclization precursor 62 has a different arrangement of the branched

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

• epoxidation, aziridination and olefination reactions [12][13] are common reaction channels. The intramolecular formation of sulfonium ylides from α-diazocarbonyl compounds tethered with alkylthio or arylthio groups has been studied by the research groups of Davies [14], Moody [15], and West [16]. From α-diazo

One-pot preparation of substituted pyrroles from α-diazocarbonyl compounds

• Fernando de C. da Silva,
• Mauricio G. Fonseca,
• Renata de S. Rianelli,
• Anna C. Cunha,
• Maria C. B. V. de Souza and
• Vitor F. Ferreira

Beilstein J. Org. Chem. 2008, 4, No. 45, doi:10.3762/bjoc.4.45

• -carbaldehyde (6) followed by reaction with primary amines. Keywords: diazocarbonyl; dihydrofuran; one-pot synthesis; pyrrole; Introduction The pyrrole unit [1] occurs in many interesting classes of compounds such as pharmaceutical agents [2][3][4][5], conducting polymers [6][7], molecular optics [8][9][10

• yield, with high atom economy, and be more convergent than one or two-component reactions. α-Diazocarbonyl compounds have a long history of useful applications in organic chemistry. They are easily prepared from readily accessible precursors and can be used in a wide variety of chemical transformations

• [28]. Indeed, we prepared several pyrroles from diazocarbonyl compounds in two steps [29] employing dihydrofurans. However, these latter compounds were difficult to prepare, isolate and transform into the pyrroles [30]. In this manuscript, we report the preparation of pyrroles from diazodicarbonyl