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

• component into a glutarimide framework employing a Rh2(esp)2-catalyzed N–H insertion with the involvement of N-Boc-α-diazo glutarimide. The new diazo reagent is more stable, soluble and convenient to prepare than the previously suggested one. The approach permits the application of diverse heterocycles

• , 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

• )-catalyzed N–H insertion reactions involving NH-heterocycles. The proposed method enables the synthesis of multigram quantities of diazo compound 5 rapidly. Furthermore, it can be stored up to several weeks in the refrigerator (5 °C) without any observable alterations. A diverse array of NH-heterocycles with

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

• cyclopropylamine. Alternatively, the formation of the enamine product could be envisaged via the reaction of the amine with bishydrazone 5, which would have formed, if the N–H insertion pathway was not sufficiently rapid. Both assumptions are in line with the formation of the similar enamine coupling product 8b

• viability of either (or both) of these possibilities is currently investigated. It should be noted that a similar Rh2(esp)2-catalyzed reaction of one of the N-aryl-α-diazo-γ-butyrolactams 1 with 2,6-dimethylaniline previously gave an excellent yield of the N–H insertion product [2]. Conclusion We

Cyclopropanation–ring expansion of 3-chloroindoles with α-halodiazoacetates: novel synthesis of 4-quinolone-3-carboxylic acid and norfloxacin

• Sara Peeters,
• Linn Neerbye Berntsen,
• Pål Rongved and
• Tore Bonge-Hansen

Beilstein J. Org. Chem. 2019, 15, 2156–2160, doi:10.3762/bjoc.15.212

• . These halo-acceptor carbenoids undergo cyclopropanation of N–H indoles with high selectivity, and only traces of C–H or N–H insertion products were observed. The yield of ethyl quinoline-3-carboxylate is dependent on the halogen in X-EDA (Cl: 90%, Br: 84%, I: 70%). The reaction works well for

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

• produce thiophenes 4 through an ordinary N–H insertion process [6][7][8][9][10][11][12][13] (Scheme 5). To the best of our knowledge, the discovered processes are the first examples of intramolecular reactions of thiocarbonyl ylides with cyano groups, acting as an electrophile, with subsequent 1,3

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

• .12.180 Abstract Rh(II)-сatalyzed reactions of aroyldiazomethanes, diazoketoesters and diazodiketones with α,β-unsaturated δ-aminoesters, in contrast to reactions of diazomalonates and other diazoesters, give rise to the Wolff rearrangement and/or oxidative cleavage of the initially formed N–H-insertion

• products. These oxidation processes are mediated by Rh(II) catalysts possessing perfluorinated ligands. The formation of pyrrolidine structures, characteristic for catalytic reactions of diazoesters, was not observed in these processes at all. Keywords: diazo compounds; N–H-insertion; oxidation cleavage

• nucleophilic 1,2-migration of aryl (Ph) or alkyl (Me) group R2 occurs, producing α-oxoketene D. The latter interacts with N–H-group of the aminoester 1 to give acylamides 6a–c. Predominance of the Wolff rearrangement over typical carbenoid reactions (N–H-insertion, etc.) in the case of diazodicarbonyl

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

• ], amides [17][18][19], and nitriles [20][21], to give N–H insertion products or N- or N,O-heterocyclic systems. The reactivity of acyl- or diacyl-substituted Rh(II) carbenoids toward an sp2-hybridized nitrogen [22][23][24] is much less studied, while examples of their reactions with 2H-azirines are unknown

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

• 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

N-Heterocyclic carbene-catalyzed direct cross-aza-benzoin reaction: Efficient synthesis of α-amino-β-keto esters

• Takuya Uno,
• Yusuke Kobayashi and
• Yoshiji Takemoto

Beilstein J. Org. Chem. 2012, 8, 1499–1504, doi:10.3762/bjoc.8.169

• migration of the N-acyl glycine derivatives [18]. The other consists of C–N bond-forming reactions, such as (c) a rhodium-catalyzed N–H insertion reaction with α-diazo-β-keto esters [19][20][21], and (d) α-oxidation of β-keto esters to the corresponding oximes and the subsequent hydrogenation [22]. However

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

• chemical processes in the fine chemical industry. In this context, we have previously reported the copper(I)-catalyzed reaction of amines with o-acetylenyl-substituted phenyldiazoacetates, which leads to a Cu(I)-catalyzed tandem N–H insertion/hydroamination of an alkyne [29]. Subsequently, we have tried to