Total synthesis of insect sex pheromones: recent improvements based on iron-mediated cross-coupling chemistry

• Eric Gayon,
• Guillaume Lefèvre,
• Olivier Guerret,
• Adrien Tintar and
• Pablo Chourreu

Beilstein J. Org. Chem. 2023, 19, 158–166, doi:10.3762/bjoc.19.15

• functionality indeed affords the terminal oxidized function of the pheromone molecule (alkoxy acetate in 2 or 3, Scheme 4a and 4b, or formyl group in 1, Scheme 4c). As a representative target, we developed the total synthesis of the codling moth sex pheromone, (8E,10E)-dodecadien-1-ol (4), featuring the

Cytochrome P450 monooxygenase-mediated tailoring of triterpenoids and steroids in plants

• Karan Malhotra and
• Jakob Franke

Beilstein J. Org. Chem. 2022, 18, 1289–1310, doi:10.3762/bjoc.18.135

• manner. MaCYP71CD2 is a bifunctional CYP that hydroxylates C23 and additionally introduces a C24–C25 epoxide on the side chain of tirucalla-7,24-dien-3β-ol (19), yielding dihydroniloticin (20). MaCYP71BQ5 then oxidises the methyl group C21 to a formyl group, leading to spontaneous hemiacetal ring

From amines to (form)amides: a simple and successful mechanochemical approach

• Federico Casti,
• Rita Mocci and
• Andrea Porcheddu

Beilstein J. Org. Chem. 2022, 18, 1210–1216, doi:10.3762/bjoc.18.126

• mechanochemical conditions. In the solvent-based procedure, imidazole has already been used in combination with DMF, which works as a solvent and source of a formyl group [23]. In that paper, the authors assumed the formation of formylimidazole as an intermediate in the formylation reaction. However, the

Morita–Baylis–Hillman reaction of 3-formyl-9H-pyrido[3,4-b]indoles and fluorescence studies of the products

• Nisha Devi and
• Virender Singh

Beilstein J. Org. Chem. 2022, 18, 926–934, doi:10.3762/bjoc.18.92

• –Spengler (P-S) or Bischler–Napieralski (B-N) cyclisation, introduction of a formyl group at C-1 or C-3 position of the β-carboline frameworks may provide a new route for generating unlimited diversity at C-1 as well as at the C-3 position of β-carbolines. As depicted in Figure 2, 1-formyl-β-carbolines and

Amamistatins isolated from Nocardia altamirensis

• Till Steinmetz,
• Wolf Hiller and
• Markus Nett

Beilstein J. Org. Chem. 2022, 18, 360–367, doi:10.3762/bjoc.18.40

• ). HMBC correlations indicated the presence of a formyl group at the ε-amino group of this residue. The fourth spin system belongs to a 1,2-disubstituted benzene moiety, featuring proton signals at δH 7.03 (dd, J = 8.3, 1.2 Hz, H-33), 7.38 (ddd, J = 8.3, 7.3, 1.7 Hz, H-34), 6.97 (ddd, J = 7.9, 7.3, 1.2 Hz

• formula of C35H53N5O8 was determined by HRESIMS with a molecular ion at m/z 672.3966 [M + H]+ (calcd for C35H54N5O9, 672.3972). Similar to 3, compound 4 is also missing a formyl group at the ε-amino group of its lysine residue. However, its increased mass of 16 Da indicates the presence of an additional

A photochemical C=C cleavage process: toward access to backbone N-formyl peptides

• Haopei Wang and
• Zachary T. Ball

Beilstein J. Org. Chem. 2021, 17, 2932–2938, doi:10.3762/bjoc.17.202

• with transfer of the C1 formyl group to compound 8. The formation of amide 2 at elevated pH could, in theory, derive from hydrolysis of the initially formed formyl product 8 (i.e. Figure 1C). However, the appearance of primarily C9 byproducts in the formation of amide 2 at elevated pH precludes

Catalytic trifluoromethylation of iodoarenes by use of 2-trifluoromethylated benzimidazoline as trifluoromethylating reagent

• Tatsuhiro Uchikura,
• Nanami Kamiyama,
• Taisuke Ishikawa and
• Takahiko Akiyama

Beilstein J. Org. Chem. 2020, 16, 2442–2447, doi:10.3762/bjoc.16.198

• p-methoxycarbonyl, were also suitable and gave products 3d–f in moderate to high yields. Furthermore, the presence of a formyl group was also tolerated in the reaction, and p-formyltrifluoromethylbenzene (3g) was obtained in 40% yield. However, the electron-rich substrate 2-methoxyiodobenzene (1h

Et₃N/DMSO-supported one-pot synthesis of highly fluorescent β-carboline-linked benzothiophenones via sulfur insertion and estimation of the photophysical properties

• Dharmender Singh,
• Vipin Kumar and
• Virender Singh

Beilstein J. Org. Chem. 2020, 16, 1740–1753, doi:10.3762/bjoc.16.146

• compared to 3-formyl-β-carbolines 3a–g which may be attributed to the higher electrophilicity of the formyl group at C1 position of the β-carboline ring. Inspired by the results of the above study, it was envisaged to check the generality of this strategy for the synthesis of β-carboline linked

Highly selective Diels–Alder and Heck arylation reactions in a divergent synthesis of isoindolo- and pyrrolo-fused polycyclic indoles from 2-formylpyrrole

• Carlos H. Escalante,
• Eder I. Martínez-Mora,
• Carlos Espinoza-Hicks,
• Alejandro A. Camacho-Dávila,
• Fernando R. Ramos-Morales,
• Francisco Delgado and
• Joaquín Tamariz

Beilstein J. Org. Chem. 2020, 16, 1320–1334, doi:10.3762/bjoc.16.113

• using manganese oxide or DDQ as the oxidizing reagents, or even including Pd/C at high temperatures (250 °C) [45], failed to obtain the series of indoles 23. It is likely that the electron withdrawing effect of the formyl group at the C-7 position counterbalance the delocalization direction of the

Synthesis of novel multifunctional carbazole-based molecules and their thermal, electrochemical and optical properties

• Nuray Altinolcek,
• Ahmet Battal,
• Mustafa Tavasli,
• William J. Peveler,
• Holly A. Yu and
• Peter J. Skabara

Beilstein J. Org. Chem. 2020, 16, 1066–1074, doi:10.3762/bjoc.16.93

• , respectively. Keywords: carbazole; electrochemistry; fluorescence; formyl group; solvatochromism; Introduction Carbazole derivatives have found many different applications in a variety of technologically important areas, such as organic light emitting diodes (OLEDs), organic photovoltaics (OPVs), dye

• . The ICT band of 7b at 373 nm was more intense than the ICT band of 7a at 378 nm. This observation confirms that conjugation enhances ICT band intensity [42]. In 7b, the formyl group is at the para position to the carbazole ring, thus giving rise to conjugation. In 7a, however, the formyl group is at

• ]. ϕFL of compounds 7a and 7b was 5.4% and 97.4%, respectively. An estimated error in quantum yield calculations is ca. 10%. The details of the calculations are given in Supporting Information File 1. Surprisingly, compound 7b, in which the formyl group is at the para position to the carbazole ring, was

Rhodium-catalyzed reductive carbonylation of aryl iodides to arylaldehydes with syngas

• Zhenghui Liu,
• Peng Wang,
• Zhenzhong Yan,
• Suqing Chen,
• Dongkun Yu,
• Xinhui Zhao and
• Tiancheng Mu

Beilstein J. Org. Chem. 2020, 16, 645–656, doi:10.3762/bjoc.16.61

• the sources of the carbonyl group and hydrogen in the formyl group. C6H513CHO, C6H5CDO, and C6H513CDO could be verified by the molecular ion peaks at m/z 107, 107, and 108 in the GC–MS spectrum of the reaction solution (for the spectrum, see Supporting Information File 1). This result confirmed that

• both CO and H2 participated in the formation of the formyl group in the product (Scheme 4a–c). Reaction mechanism and role of each component Based on the results from the labeling experiments a reaction mechanism for the reductive carbonylation of aryl iodides was proposed, as shown in Scheme 5 [57

Functionalization of 4-bromobenzo[c][2,7]naphthyridine via regioselective direct ring metalation. A novel approach to analogues of pyridoacridine alkaloids

• Benedikt C. Melzer,
• Alois Plodek and
• Franz Bracher

Beilstein J. Org. Chem. 2019, 15, 2304–2310, doi:10.3762/bjoc.15.222

• amphimedine (1) [11]. 4-Chloro-5-methylbenzo[c][2,7]naphthyridine (8) was oxidized at the methyl group to give an aldehyde. Subsequent modifications of the formyl group and Stille couplings at C-4 gave a number of 4,5-disubstituted benzo[c][2,7]naphthyridines (Figure 2A) [12]. Organolithium compounds were

An overview of the cycloaddition chemistry of fulvenes and emerging applications

• Ellen Swan,
• Kirsten Platts and
• Anton Blencowe

Beilstein J. Org. Chem. 2019, 15, 2113–2132, doi:10.3762/bjoc.15.209

• found to occur between the fulvene and an enamine generated through the reaction of the formyl group with the organocatalyst, diphenylprolinol silyl ether. Variation of the spacer structure provided access to a range of triquinane derivatives (Scheme 11), an important precursor in biomimetic and natural

Reactions of 2-carbonyl- and 2-hydroxy(or methoxy)alkyl-substituted benzimidazoles with arenes in the superacid CF₃SO₃H. NMR and DFT studies of dicationic electrophilic species

• Dmitry S. Ryabukhin,
• Alexey N. Turdakov,
• Natalia S. Soldatova,
• Mikhail O. Kompanets,
• Alexander Yu. Ivanov,
• Irina A. Boyarskaya and
• Aleksander V. Vasilyev

Beilstein J. Org. Chem. 2019, 15, 1962–1973, doi:10.3762/bjoc.15.191

• –8 with arenes under the action of Brønsted acids (H2SO4, TfOH) or Lewis acids (AlX3, X = Cl, Br). Reactions of 2-formyl-1-methylbenzimidazole (1) with various arenes (benzene, and its methyl, methoxy or chloro-substituted derivatives) are given in Table 3. These reactions proceed on the formyl group

Introduction of an isoxazoline unit to the β-position of porphyrin via regioselective 1,3-dipolar cycloaddition reaction

• Xiujun Liu,
• Xiang Ma and
• Yaqing Feng

Beilstein J. Org. Chem. 2019, 15, 1434–1440, doi:10.3762/bjoc.15.143

• Vilsmeier reaction was carried out after insertion of Cu2+ into the cavity of TPP. In the presence of concentrated H2SO4 the Cu2+ was removed to give the 2-formyl derivative TPP-CHO. Subsequently, the formyl group was reduced by NaBH4, accompanied with chlorination by SOCl2, to afford the chloromethyl

Multicomponent reactions (MCRs): a useful access to the synthesis of benzo-fused γ-lactams

• Edorta Martínez de Marigorta,
• Jesús M. de Los Santos,
• Ana M. Ochoa de Retana,
• Javier Vicario and
• Francisco Palacios

Beilstein J. Org. Chem. 2019, 15, 1065–1085, doi:10.3762/bjoc.15.104

• through an addition of copper acetylide, generated from terminal alkyne and copper, to the imine formed by the reaction between the amine and the formyl group. Then, the secondary propargylamine intermediate would act as a nucleophile in a cyclization process to form the lactam ring. The same

The LANCA three-component reaction to highly substituted β-ketoenamides – versatile intermediates for the synthesis of functionalized pyridine, pyrimidine, oxazole and quinoxaline derivatives

• Tilman Lechel,
• Roopender Kumar,
• Mrinal K. Bera,
• Reinhold Zimmer and
• Hans-Ulrich Reissig

Beilstein J. Org. Chem. 2019, 15, 655–678, doi:10.3762/bjoc.15.61

• . The easily introduced C-2 alkenyl groups may also be oxidized. Thus, dihydroxylation of the vinyl group in PM7 followed by oxidative cleavage afforded pyrimidine derivative PM50 having a formyl group at C-2 (Scheme 12) [31]. Next, the conversion of the 5-alkoxy groups of the pyrimidine derivatives PM

• oxidations of PM5, PM9, PM15 and PM19 furnishing aldehydes PM41, PM42, PM44 and PM48 are shown in Scheme 11 [33]. In case of the benzyl-substituted substrate PM5, the (probably faster) oxidation of the C-2 benzyl group could not be avoided and hence the dicarbonyl compound PM41 was isolated [50]. The formyl

• group of the prepared intermediates allows further conversion into other functional groups as depicted in the scheme. Wittig reactions provided 4-alkenyl-substituted pyrimidine derivatives such as PM43 or PM47, whereas further oxidation of PM44 afforded the carboxylic acid PM45 in good yield [33

A selective removal of the secondary hydroxy group from ortho-dithioacetal-substituted diarylmethanols

• Anna Czarnecka,
• Emilia Kowalska,
• Agnieszka Bodzioch,
• Joanna Skalik,
• Marek Koprowski,
• Krzysztof Owsianik and
• Piotr Bałczewski

Beilstein J. Org. Chem. 2018, 14, 1229–1237, doi:10.3762/bjoc.14.105

• procedure shown in Scheme 2 including: 1) protection of the formyl group in ortho-bromoaldehydes 1 and 2 with 1,3-propanedithiol, 2) the Br/Li exchange reaction in the resulting ortho-bromo-1,3-dithianes 3 and 4 with n-BuLi followed by condensation with a second (hetero)aromatic aldehyde Ar2-CHO. The

Nucleophilic fluoroalkylation/cyclization route to fluorinated phthalides

• Masanori Inaba,
• Tatsuya Sakai,
• Shun Shinada,
• Tsuyuka Sugiishi,
• Yuta Nishina,
• Norio Shibata and
• Hideki Amii

Beilstein J. Org. Chem. 2018, 14, 182–186, doi:10.3762/bjoc.14.12

• assuming the pathway shown in Scheme 2. The formyl group in aldehyde 2 undergoes nucleophilic trifluoromethylation triggered by a catalytic amount of KF to give the ortho-cyanobenzyl silyl ether 3. Upon treatment with aq HCl, the subsequent lactonization of 4 takes place to afford trifluoromethylphthalide

Conjugated nitrosoalkenes as Michael acceptors in carbon–carbon bond forming reactions: a review and perspective

• Yaroslav D. Boyko,
• Valentin S. Dorokhov,
• Alexey Yu. Sukhorukov and
• Sema L. Ioffe

Beilstein J. Org. Chem. 2017, 13, 2214–2234, doi:10.3762/bjoc.13.220

• corresponding adduct 44 in 93% yield. Importantly, both stereoisomers obtained were oxime E,Z-isomers with the C-7 relative configuration being the same as in myrioneurinol. Subsequent deoxygenation and reduction of aldoxime followed by transformation of the malonate unit to the formyl group furnished

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

• a formyl group attached to C8’ and a single bond between C8’ and C9’ (mycolactone G, 10). Due to its unspecific appearance at early stages, the diagnosis of Buruli ulcer is non-trivial and no point-of-care rapid diagnostic test is currently available [64]. Identification of the infection generally

New electroactive asymmetrical chalcones and therefrom derived 2-amino- / 2-(1H-pyrrol-1-yl)pyrimidines, containing an N-[ω-(4-methoxyphenoxy)alkyl]carbazole fragment: synthesis, optical and electrochemical properties

• Daria G. Selivanova,
• Alexei A. Gorbunov,
• Olga A. Mayorova,
• Alexander N. Vasyanin,
• Igor V. Lunegov,
• Elena V. Shklyaeva and
• Georgii G. Abashev

Beilstein J. Org. Chem. 2017, 13, 1583–1595, doi:10.3762/bjoc.13.158

• substituent at the C3 atom of the carbazole cycle: 2a,b – formyl group, 3a,b – acetyl group, 4a,b – 1-chloro-3-oxoprop-1-en-1-yl moiety and 5a,b – 5-acetylthiophen-2-yl unit. That’s why it is interesting to compare their optical properties. So, we have fulfilled the overlapping of the absorption and emission

Nitration of 5,11-dihydroindolo[3,2-b]carbazoles and synthetic applications of their nitro-substituted derivatives

• Roman A. Irgashev,
• Nikita A. Kazin,
• Gennady L. Rusinov and
• Valery N. Charushin

Beilstein J. Org. Chem. 2017, 13, 1396–1406, doi:10.3762/bjoc.13.136

• performed by using the Suzuki–Miyaura cross-coupling reaction with phenylboronic acid under Pd catalysis (Scheme 5). The location of the formyl group and bromine atoms in ICZ derivatives 12 and 13 has been established by X-ray crystallography analysis, performed for single crystals of 12b and 13b (Figure 5

Biosynthesis of oxygen and nitrogen-containing heterocycles in polyketides

• Franziska Hemmerling and
• Frank Hahn

Beilstein J. Org. Chem. 2016, 12, 1512–1550, doi:10.3762/bjoc.12.148

Reactions of N,3-diarylpropiolamides with arenes under superelectrophilic activation: synthesis of 4,4-diaryl-3,4-dihydroquinolin-2(1H)-ones and their derivatives

• Larisa Yu. Gurskaya,
• Diana S. Belyanskaya,
• Dmitry S. Ryabukhin,
• Denis I. Nilov,
• Irina A. Boyarskaya and
• Aleksander V. Vasilyev

Beilstein J. Org. Chem. 2016, 12, 950–956, doi:10.3762/bjoc.12.93

• superelectrophilic activation of the N-formyl group by TfOH in the reaction with benzene resulted in the formation of N-(diphenylmethyl)-substituted dihydroquinolinones. Keywords: alkynes; quinolinones; Friedel–Crafts reactions; superacids; superelectrophilic activation; Introduction Quinoline derivatives are a

• of compounds 5 and 6 with arenes in TfOH were checked. Analogously to other heteroaromatic aldehydes of the series of pyridine [19], quinolone [20], pyrazol [21], and imidazole [22], the superelectrophilic activation of the formyl group in 5 was expected. Indeed, compounds 5a,b and d reacted with

• two positive charges in C substantially increases the electrophilic properties of the carbon of the O-protonated N-formyl group and explains its reactivity. The reactions of 5 with other arenes, such as 1,2-dichlorobenzene, toluene, or isomeric xylenes, gave deformylation products 2. In this case