Recent advances in transition-metal-free arylation reactions involving hypervalent iodine salts

• Ritu Mamgain,
• Kokila Sakthivel and
• Fateh V. Singh

Beilstein J. Org. Chem. 2024, 20, 2891–2920, doi:10.3762/bjoc.20.243

• arylation; rearrangement reaction; Introduction The chemistry of hypervalent iodine compounds is well-established and they are prevalent as oxidants and electrophilic reagents in organic conversions [1][2][3]. They have gained significant attention due to their high reactivity and ability to carry out

Visible-light-mediated flow protocol for Achmatowicz rearrangement

• Joachyutharayalu Oja,
• Sanjeev Kumar and
• Srihari Pabbaraja

Beilstein J. Org. Chem. 2024, 20, 2493–2499, doi:10.3762/bjoc.20.213

• platforms, we herein present a photo-flow platform for Achmatowicz reactions. A novel photo-flow solar panel reactor was fabricated to test and validate the Achmatowicz rearrangement reaction (Figure S1, Supporting Information File 1), and the reaction conditions were optimized with a ruthenium catalyst. As

• Information File 1). This reactor was then exposed to sunlight/handmade LED to carry out the Achmatowicz rearrangement reaction. To test the model reaction's feasibility, a stock solution containing ethyl 3-(furan-2-yl)-3-hydroxypropanoate (2a)/Ru(bpy)3Cl2·6H2O/K2S2O8/ACN (2 mL)/DMSO (2 mL)/H2O (4 mL) as a

• rearrangement reaction [7][8][9][10][14][15]. With the established photo-flow platform and optimized conditions, we were interested in investigating the scope of this methodology using several substituted furfuryl alcohol substrates (2a–p) which were subjected to the Achmatowicz reaction utilizing our photo

Cofactor-independent C–C bond cleavage reactions catalyzed by the AlpJ family of oxygenases in atypical angucycline biosynthesis

• Jinmin Gao,
• Liyuan Li,
• Shijie Shen,
• Guomin Ai,
• Bin Wang,
• Fang Guo,
• Tongjian Yang,
• Hui Han,
• Zhengren Xu,
• Guohui Pan and
• Keqiang Fan

Beilstein J. Org. Chem. 2024, 20, 1198–1206, doi:10.3762/bjoc.20.102

• cofactor-independent manner. Keywords: angucyclines; aromatic polyketide; biosynthesis; cofactor-independent oxygenase; oxidative rearrangement reaction; Introduction The angucyclines represent a large class of natural products biosynthesized by type II polyketide synthases. Within this category, a

Skeletal rearrangement of 6,8-dioxabicyclo[3.2.1]octan-4-ols promoted by thionyl chloride or Appel conditions

• Martyn Jevric,
• Julian Klepp,
• Johannes Puschnig,
• Oscar Lamb,
• Christopher J. Sumby and
• Ben W. Greatrex

Beilstein J. Org. Chem. 2024, 20, 823–829, doi:10.3762/bjoc.20.74

• during chromatography, and so an alternate method was developed to generate a single product by promoting the formation of the hemiacetal series 12a–f. Following the rearrangement reaction, chromatography of the chlorides using silica with 2% water added led to the isolation of 12a,c–f in good yield

• described for the first time. The work builds upon the findings of the groups of Karban and Banwell, who described this type of ring transformation using DAST, with two new reagents for promoting the rearrangement reaction. This work adds to the growing set of transformations that are known for

Unraveling the role of prenyl side-chain interactions in stabilizing the secondary carbocation in the biosynthesis of variexenol B

• Moe Nakano,
• Rintaro Gemma and
• Hajime Sato

Beilstein J. Org. Chem. 2023, 19, 1503–1510, doi:10.3762/bjoc.19.107

• as the C–H–π interaction between the carbocation intermediate and the Phe residue of terpene cyclase in the biosynthesis of sesterfisherol [21], and the intricated rearrangement reaction mechanism promoted by the equilibrium state of the homoallyl cation and the cyclopropylcarbinyl cation in the

Inductive heating and flow chemistry – a perfect synergy of emerging enabling technologies

• Conrad Kuhwald,
• Sibel Türkhan and
• Andreas Kirschning

Beilstein J. Org. Chem. 2022, 18, 688–706, doi:10.3762/bjoc.18.70

• (reaction 1) and steam (reaction 2) methane reforming. Calcination and RF heating. The continuously operated “Sabatier” process. Biofuel production from biomass using inductive heating for pyrolysis. Water electrolysis using an inductively heated electrolysis cell. Dimroth rearrangement (reaction 1) and

α-Ketol and α-iminol rearrangements in synthetic organic and biosynthetic reactions

• Scott Benz and
• Andrew S. Murkin

Beilstein J. Org. Chem. 2021, 17, 2570–2584, doi:10.3762/bjoc.17.172

• determined by 1H NMR). Additionally, purified 42 was not observed to undergo any α-ketol rearrangement reaction, although the authors did not discuss why the reverse reaction did not occur. As was alluded to earlier, tandem reactions that include an α-ketol rearrangement have been incorporated into some

Advances in mercury(II)-salt-mediated cyclization reactions of unsaturated bonds

• Sumana Mandal,
• Raju D. Chaudhari and
• Goutam Biswas

Beilstein J. Org. Chem. 2021, 17, 2348–2376, doi:10.3762/bjoc.17.153

• corresponding methoxyarylalkyne derivative 105 (Scheme 31). In 2005, Ghorai et al. reported the synthesis of a mixture of 6-membered as well as 5-membered heterocyclic compounds through a Hg(II)-salt-promoted unique cyclization–rearrangement reaction [85]. They had performed the HgCl2-promoted cyclization of O

Total synthesis of pyrrolo[2,3-c]quinoline alkaloid: trigonoine B

• Takashi Nishiyama,
• Erina Hamada,
• Daishi Ishii,
• Yuuto Kihara,
• Nanase Choshi,
• Natsumi Nakanishi,
• Mari Murakami,
• Kimiko Taninaka,
• Noriyuki Hatae and
• Tominari Choshi

Beilstein J. Org. Chem. 2021, 17, 730–736, doi:10.3762/bjoc.17.62

• prepared from an appropriate carboxylic acid through a Curtius rearrangement reaction (50–98% yield). Treatment of urea derivatives 19a–d with CBr4, PPh3, and Et3N afforded carbodiimides 20a–d in 64–75% yield. Compounds 21a–d were obtained in situ following the removal of the TIPS protecting group in 20a–d

CF₃-substituted carbocations: underexploited intermediates with great potential in modern synthetic chemistry

• Anthony J. Fernandes,
• Armen Panossian,
• Bastien Michelet,
• Agnès Martin-Mingot,
• Frédéric R. Leroux and
• Sébastien Thibaudeau

Beilstein J. Org. Chem. 2021, 17, 343–378, doi:10.3762/bjoc.17.32

Synthesis of C₇₀-fragment buckybowls bearing alkoxy substituents

• Yumi Yakiyama,
• Shota Hishikawa and
• Hidehiro Sakurai

Beilstein J. Org. Chem. 2020, 16, 681–690, doi:10.3762/bjoc.16.66

• for the rearrangement reaction In a similar manner as described in [18], to the mixture of 3 (0.19 mmol) and p-toluenesulfonic acid (0.19 mmol) was added a dry toluene (20 mL). The mixture was refluxed with stirring for 1 h. After the addition of sat. NaHCO3aq, the mixture was extracted with CH2Cl2

Regio- and stereoselective synthesis of new ensembles of diversely functionalized 1,3-thiaselenol-2-ylmethyl selenides by a double rearrangement reaction

• Svetlana V. Amosova,
• Andrey A. Filippov,
• Nataliya A. Makhaeva,
• Alexander I. Albanov and
• Vladimir A. Potapov

Beilstein J. Org. Chem. 2020, 16, 515–523, doi:10.3762/bjoc.16.47

Safe and highly efficient adaptation of potentially explosive azide chemistry involved in the synthesis of Tamiflu using continuous-flow technology

• Cloudius R. Sagandira and
• Paul Watts

Beilstein J. Org. Chem. 2019, 15, 2577–2589, doi:10.3762/bjoc.15.251

• effort to address the safety concerns raised by the potentially explosive acyl azide 1a (Scheme 1), Hayashi and co-workers [14] demonstrated the handling of the Curtius rearrangement reaction (transformation from acyl azide 1a to isocyanate 1b) in a microreactor system (Scheme 1 and Figure 1). Acyl azide

Chiral terpene auxiliaries V: Synthesis of new chiral γ-hydroxyphosphine oxides derived from α-pinene

• Anna Kmieciak and
• Marek P. Krzemiński

Beilstein J. Org. Chem. 2019, 15, 2493–2499, doi:10.3762/bjoc.15.242

• rearrangement reaction may be the rigid bicyclic structure of the substrate and steric hindrance on one side of the molecule caused by the gem-dimethyl bridge. Conclusion Regioisomeric exocyclic allylic alcohols were synthesized from natural α-pinene. (1R,2R,4S,5R)-3-Methyleneneoisoverbanol and (1R,2R,3R,5R)-4

Synthesis of a dihalogenated pyridinyl silicon rhodamine for mitochondrial imaging by a halogen dance rearrangement

• Jessica Matthias,
• Thines Kanagasundaram,
• Klaus Kopka and
• Carsten S. Kramer

Beilstein J. Org. Chem. 2019, 15, 2333–2343, doi:10.3762/bjoc.15.226

• exchange with n-BuLi, was initially published and investigated by Mallet et al. who also investigated and termed the mechanism “homotransmetallation” [47]. The HD rearrangement reaction in general is an excellent method for the construction of highly substituted carbo- and heterocyclic systems (e.g

Robust perfluorophenylboronic acid-catalyzed stereoselective synthesis of 2,3-unsaturated O-, C-, N- and S-linked glycosides

• Madhu Babu Tatina,
• Xia Mengxin,
• Rao Peilin and
• Zaher M. A. Judeh

Beilstein J. Org. Chem. 2019, 15, 1275–1280, doi:10.3762/bjoc.15.125

• perflurophenylboronic acid as a versatile organocatalyst for the Ferrier rearrangement reaction. We noted that the yields of the disaccharides 3n and 3o and sulfonamides 3t and 3u can be increased with increase in the temperature (60 °C) and extension of the reaction time. The results in Table 1 are superior to the

Revisiting ring-degenerate rearrangements of 1-substituted-4-imino-1,2,3-triazoles

• James T. Fletcher,
• Matthew D. Hanson,
• Joseph A. Christensen and
• Eric M. Villa

Beilstein J. Org. Chem. 2018, 14, 2098–2105, doi:10.3762/bjoc.14.184

• forward rearrangement reaction and subsequent imine hydrolysis due to its nucleophilic incompetency, the para-nitroaniline byproduct formed in the condensation/rearrangement/hydrolysis might also serve as a colorimetric self-indicator of reaction progress, as illustrated in Figure 4. In order to test the

• rearrangement reaction will be the subject of future studies. Conclusion Motivated by an interest in the 4-imino-1,2,3-triazole synthon, the goal of this investigation was to better understand the susceptibility of such molecules to the ring-degenerate rearrangements first described by L’abbé in 1990 [42]. By

• –8.7 ppm correspond to the triazole C–H position used to quantify the imine constituents of product mixtures. Rearrangement reaction progress of 1a leading to irreversible formation of a colorimetric self-indicating byproduct. Evaluation of symmetrical condensation parameters. Evaluation of

Cationic cobalt-catalyzed [1,3]-rearrangement of N-alkoxycarbonyloxyanilines

• Itaru Nakamura,
• Mao Owada,
• Takeru Jo and
• Masahiro Terada

Beilstein J. Org. Chem. 2018, 14, 1972–1979, doi:10.3762/bjoc.14.172

• labelling experiments indicate that the rearrangement of the alkoxycarbonyloxy group proceeds in [1,3]-manner. In this article, we discuss the overall picture of the cobalt-catalysed [1,3]-rearrangement reaction including details of the reaction conditions and substrate scope. Keywords: anilines; cobalt

• to the strongly electron-withdrawing nature of the sulfonyl group (Scheme 2b) [12]. Accordingly, we envisioned that appropriate Lewis acidic metal catalysts would promote the rearrangement reaction of stable N-acyloxyanilines to afford readily deprotectable 2-acyloxyanilines under much milder

• mechanistic studies revealed that the rearrangement of the alkoxycarbonyloxy group proceeded in an unprecedented [1,3]-manner (Scheme 2c). In this article, we describe the overall picture of the intriguing [1,3]-rearrangement reaction, particularly the detail of the reaction, which were not sufficiently

Synthesis of new tricyclic 5,6-dihydro-4H-benzo[b][1,2,4]triazolo[1,5-d][1,4]diazepine derivatives by [3⁺ + 2]-cycloaddition/rearrangement reactions

• Lin-bo Luan,
• Zi-jie Song,
• Zhi-ming Li and
• Quan-rui Wang

Beilstein J. Org. Chem. 2018, 14, 1826–1833, doi:10.3762/bjoc.14.155

• followed by a ring-expansion rearrangement. In the rearrangement reaction, the phenyl substituent in the initially formed spiro-triazolium adducts 16 underwent a [1,2]-migration from C(3) to the electron-deficient N(2). This led to the ring expansion from 6-membered piperidine to 7-membered diazepine

• + + 2]-cycloaddition, α-acetoxyazo intermediates are initially transformed into an azocarbenium ion. Subsequently, it takes part in a cationic cycloaddition reaction with the triple bond of a nitrile followed by a rearrangement reaction [35][36][37][38][39]. This type of ionic cycloaddition

• electron-withdrawing N-acetyl functionality in compounds 8 was introduced to conceal the basicity of the N(1) atom, thus avoiding the plausible disturbance in the following cationic polar cycloaddition/rearrangement reaction. After the accomplishment of the synthesis of key intermediates 8, we tried to

The phenyl vinyl ether–methanol complex: a model system for quantum chemistry benchmarking

• Dominic Bernhard,
• Fabian Dietrich,
• Mariyam Fatima,
• Cristóbal Pérez,
• Hannes C. Gottschalk,
• Axel Wuttke,
• Ricardo A. Mata,
• Martin A. Suhm,
• Melanie Schnell and
• Markus Gerhards

Beilstein J. Org. Chem. 2018, 14, 1642–1654, doi:10.3762/bjoc.14.140

• ). Nevertheless, due to the predicted red-shifts of the OH stretching frequencies of the OH–P isomers (indicating an increased hydrogen bond strength compared to the S0 state), their presence, i.e., by a rearrangement reaction from the OH–O’ isomer, can be excluded. By exciting the electronic origin of the OH–O

Synthesis and stability of strongly acidic benzamide derivatives

• Frederik Diness,
• Niels J. Bjerrum and
• Mikael Begtrup

Beilstein J. Org. Chem. 2018, 14, 523–530, doi:10.3762/bjoc.14.38

• in a ruthenium-catalyzed C–H activation reaction [36]. Most other reported transformations pass via the imidoyl chloride intermediates (equivalent to 10) to the amidine derivatives, which have been used in rearrangement reaction studies [9][37][38][39]. By these means also N,N’-bis(triflyl

Chiral phase-transfer catalysis in the asymmetric α-heterofunctionalization of prochiral nucleophiles

• Johannes Schörgenhumer,
• Maximilian Tiffner and
• Mario Waser

Beilstein J. Org. Chem. 2017, 13, 1753–1769, doi:10.3762/bjoc.13.170

• -workers demonstrated the potential of asymmetric cation-based phase-transfer catalysis to control the absolute configuration of the newly-installed stereogenic centre in this rearrangement reaction [141]. By using their spiro-quaternary ammonium salt catalyst B5 they were able to control the Neber

Synthesis of pyrrolo[2,1-f][1,2,4]triazin-4(3H)-ones: Rearrangement of pyrrolo[1,2-d][1,3,4]oxadiazines and regioselective intramolecular cyclization of 1,2-biscarbamoyl-substituted 1H-pyrroles

• Kkonnip Son and
• Seong Jun Park

Beilstein J. Org. Chem. 2016, 12, 1780–1787, doi:10.3762/bjoc.12.168

• the reported rearrangement reaction, the desired product 12a’ was not accessed (approach B, Scheme 1). For the procedure using silica-gel column chromatography to afford triazinone 12a’ from the free amine-containing oxadiazine 11a’ [10], compound 11a’ was not present after the boc-deprotection

• rearrangement reaction of pyrrolooxadiazine 11a to pyrrolotriazinone 12a was explored (Table 2). For nucleophile-induced cyclization, pyrrolidine, Li(Me3AlSPh) [22], NaSMe, and NaOMe were assessed. Attempting the Mazurciewitcz–Ganesan procedure [23], using pyrrolidine as a nucleophile, was not successful (entry

• conditions (0 °C, 5 min). The regioselectivity was influenced by the identities of halogen sources of triphenylphosphorane and the N-functional groups. For the rearrangement reaction, it was demonstrated that triazinone 12a was easily obtained when counter ions of oxygen such as lithium and sodium were used

The role of alkyl substituents in deazaadenine-based diarylethene photoswitches

• Christopher Sarter,
• Michael Heimes and
• Andres Jäschke

Beilstein J. Org. Chem. 2016, 12, 1103–1110, doi:10.3762/bjoc.12.106

• further supported by the appearance of two new signals in the NMR spectrum of an extensively irradiated solution of 1d at δ = 2.53 and 2.71 (Supporting Information File 1, Figure S7), in agreement with values reported for isolated products of this rearrangement reaction [49]. Methyl switch 1a, pyridyl

Dynamic behavior of rearranging carbocations – implications for terpene biosynthesis

• Stephanie R. Hare and
• Dean J. Tantillo

Beilstein J. Org. Chem. 2016, 12, 377–390, doi:10.3762/bjoc.12.41

• ), the results just described could be anticipated. The IRC for the dehydration-rearrangement reaction actually proceeds through the region where the secondary carbocation resides, even though this structure is not a PES minimum. The curvature of the IRC in this region would likely have indicated the