Transition-metal-catalyzed domino reactions of strained bicyclic alkenes

• Austin Pounder,
• Eric Neufeld,
• Peter Myler and
• William Tam

Beilstein J. Org. Chem. 2023, 19, 487–540, doi:10.3762/bjoc.19.38

• 5.0 equivalents of Cs2CO3 provided the naphthalene core via sequential dehydration. Based on preliminary mechanistic experiments, the authors proposed the reaction begins with the oxidation of Co(II) to Co(III) by O2. MHP-directed C–H activation of the ortho-C–H position generates 90 which can

• reaction to afford the naphthalene product 88a. Inspired by Zhao’s seminal report on the racemic carboamination of bicyclic alkenes [53], the Cramer laboratory studied the Co-catalyzed enantioselective carboamination of bicyclic alkenes 1 via C–H functionalization in 2021 (Scheme 17) [54]. The authors

• azabicyclic alkenes 30 (Scheme 29) [75]. When investigating the reaction with oxabenzonorbornadiene (30b), the resulting product was found to exclusively be the dehydrated 2-naphthalene derivative 166. It was found that the addition of pivalic acid greatly improved the yield, likely due to its facilitation of

Transition-metal-catalyzed C–H bond activation as a sustainable strategy for the synthesis of fluorinated molecules: an overview

• Louis Monsigny,
• Floriane Doche and
• Tatiana Besset

Beilstein J. Org. Chem. 2023, 19, 448–473, doi:10.3762/bjoc.19.35

• allowing the formation of a C(sp2)–ORF bond through palladium-catalyzed C–H bond activation [169]. Using Pd(OPiv)2 as the catalyst in the presence of PhI(OAc)2 (PIDA), the naphthalene sulfoxide 43a was 2,2,2-trifluoroethoxylated in 82% yield (Scheme 21). The substituent of the sulfoxide part does not

• -sulfonylbenzamides reported by the group of Ji and Li [150]. a50 °C. b15 equiv TFA. c5 equiv TFA. dN-acetylglycine (60 mol %). Ns: 4-nitrobenzenesulfonyl. Pd(II)-catalyzed selective 2,2,2-trifluoroethoxylation and other fluoroalkoxylations of naphthalene sulfoxide derivatives reported by the group of Yorimitsu [169

Preparation of β-cyclodextrin/polysaccharide foams using saponin

• Max Petitjean and
• José Ramón Isasi

Beilstein J. Org. Chem. 2023, 19, 78–88, doi:10.3762/bjoc.19.7

• complexing with the PAH and having repulsive interactions with soil [21]. A large quantity of HOCs have been studied, such as naphthalene or fluoranthene [19]. The authors reported also the possibility of remediation of heavy metals by saponins [22]. Therefore, saponins are useful in soil washing

Improving the accuracy of ³¹P NMR chemical shift calculations by use of scaling methods

• William H. Hersh and
• Tsz-Yeung Chan

Beilstein J. Org. Chem. 2023, 19, 36–56, doi:10.3762/bjoc.19.4

• for the P–P-bonded compounds was that of PB in 8 of up to roughly 40 ppm. An alternative hypothesis for this deviation might be that it could be due to multiple P–C bond character rather than the P–P bond itself, due to π overlap of dicoordinate PB with the naphthalene ring. The MAD/RMSD values for

Electrochemical vicinal oxyazidation of α-arylvinyl acetates

• Yi-Lun Li,
• Zhaojiang Shi,
• Tao Shen and
• Ke-Yin Ye

Beilstein J. Org. Chem. 2022, 18, 1026–1031, doi:10.3762/bjoc.18.103

• ), chloro (16), and bromo (17), proceeded with the anticipated reactivity less efficiently (30–48% yields). The presence of other electron-withdrawing groups, such as CO2Me (18) and OCF3 (19), exhibited similar negative effects on the reaction yields. Naphthalene (20), thiophene (21), benzothiophene (22

Electrochemical and spectroscopic properties of twisted dibenzo[g,p]chrysene derivatives

• Tomoya Imai,
• Ryuhei Akasaka,
• Naruhiro Yoshida,
• Toru Amaya and
• Tetsuo Iwasawa

Beilstein J. Org. Chem. 2022, 18, 963–971, doi:10.3762/bjoc.18.96

• , Otsu, Shiga, 520-2194, Japan 10.3762/bjoc.18.96 Abstract Dibenzo[g,p]chrysene (DBC), which consists of a twisted naphthalene core with four fused benzene rings, is a promising framework for organic electronic materials. Therefore, the research for structure–property relationships is important for the

• design of DBC-based materials. Here, the electrochemical and spectroscopic properties of DBC derivatives were investigated, and the effects of substituents and torsion of the naphthalene moiety were examined based on density functional theory (DFT) calculations. All the substituted DBC derivatives showed

• the benzene ring because of the steric repulsion of substituents on both sides. More specifically, the inductive effect of the MeO group is dominant rather than the mesomeric effect when the substituent is located at both sides of the MeO group. Concerning the torsion of the naphthalene moiety, the

Electroreductive coupling of 2-acylbenzoates with α,β-unsaturated carbonyl compounds: density functional theory study on product selectivity

• Naoki Kise and
• Toshihiko Sakurai

Beilstein J. Org. Chem. 2022, 18, 956–962, doi:10.3762/bjoc.18.95

• vinyl ketone (2b) and subsequent treatment with 1 M HCl afforded phthalides 5a–h in moderate to good yields and naphthalene-1-ols 3’ corresponding to cyclized products 3 were not formed at all (Table 2). The Ep values of substrates 1a–h were observed to be in the range from −1.74 to −1.96 V versus SCE

Thiophene/selenophene-based S-shaped double helicenes: regioselective synthesis and structures

• Mengjie Wang,
• Lanping Dang,
• Wan Xu,
• Zhiying Ma,
• Liuliu Shao,
• Guangxia Wang,
• Chunli Li and
• Hua Wang

Beilstein J. Org. Chem. 2022, 18, 809–817, doi:10.3762/bjoc.18.81

• annulene [12], and twisted naphthalene as central spacers [19]. As its close analogue, selenophene has properties very similar to those of thiophene. Fused aromatic compounds containing selenophene units show favorable optical and electrochemical properties and improved charge transport characteristics in

• S21). However, after the formation of the naphthalene ring, the α-position is the most likely site for reaction (Supporting Information File 1, Figure S22). Therefore, after the double oxidative photocyclization of compound 5a, product DH-1 is mainly obtained. The predicted result of the double

• helicenes have the same configuration and bend toward the same direction on the same side of the shared naphthalene ring (Figure 3C and D). Both products DH-1 or DH-2 feature a pair of enantiomers MM and PP in their unit cell (see Supporting Information File 2, Figures S2 and S6). The crystal parameters of

Synthesis of α-(perfluoroalkylsulfonyl)propiophenones: a new set of reagents for the light-mediated perfluoroalkylation of aromatics

• Durbis J. Castillo-Pazos,
• Juan D. Lasso and
• Chao-Jun Li

Beilstein J. Org. Chem. 2022, 18, 788–795, doi:10.3762/bjoc.18.79

• ), both in less than 6 hours (Scheme 5). Unsubstituted arenes such as naphthalene were well tolerated in this methodology and produced 72% isolated yield of the perfluorohexylated product 11b. The radical addition to unsubstituted benzene was also found to be possible affording perfluorooctylated product

DDQ in mechanochemical C–N coupling reactions

• Shyamal Kanti Bera,
• Rosalin Bhanja and
• Prasenjit Mal

Beilstein J. Org. Chem. 2022, 18, 639–646, doi:10.3762/bjoc.18.64

• reacted smoothly with various substituted aldehydes (containing a bromo, fluoro, hydroxy, chloro, ethyl, or methyl group) affording the corresponding products 5b–g with good to excellent yields. Also, 3,4,5-trimethoxy-, 2,4,6-trimethyl-, anthracene-9-yl-, and naphthalene-1-yl-substituted benzaldehydes

Menadione: a platform and a target to valuable compounds synthesis

• Acácio S. de Souza,
• Ruan Carlos B. Ribeiro,
• Dora C. S. Costa,
• Fernanda P. Pauli,
• David R. Pinho,
• Matheus G. de Moraes,
• Fernando de C. da Silva,
• Luana da S. M. Forezi and
• Vitor F. Ferreira

Beilstein J. Org. Chem. 2022, 18, 381–419, doi:10.3762/bjoc.18.43

• hydroquinone ethers [87]. The combination of tert-butyl hydroperoxide and poly(bis-1,2-phenyl)diselenide was the one that showed the best result: 90% yield after 12 h reaction and recrystallization (Table 3, entry 3). Construction of the naphthoquinone ring In addition to the oxidation of naphthalene

A resorcin[4]arene hexameric capsule as a supramolecular catalyst in elimination and isomerization reactions

• Tommaso Lorenzetto,
• Fabrizio Fabris and
• Alessandro Scarso

Beilstein J. Org. Chem. 2022, 18, 337–349, doi:10.3762/bjoc.18.38

• obtained by the same group with a larger tetrahedral capsule using pyrene in place of naphthalene units observing isopulegol, neoisopulegol and neoisoisopulegol with 71%, 24% and 4% selectivity [52]. The comparison between the metal-ligand tetrahedral capsules and the H-bonded 16 shows a common trend of

Site-selective reactions mediated by molecular containers

• Rui Wang and
• Yang Yu

Beilstein J. Org. Chem. 2022, 18, 309–324, doi:10.3762/bjoc.18.35

• accommodated in the cavity of A through π–π stacking interactions between the naphthalene ring of 3 and a triazine ligand of A from the X-ray crystallographic analysis. In the control experiment, without host A, only 44% yield of the conventional 9,10-adduct 4 was produced without any 1,4-adduct product

• reactions. Naphthalene is usually hard to undergo Diels–Alder reactions [44][45][46], even though the quantum-mechanical and thermochemical calculations suggest that the reaction is exothermic, which indicates the entropic cost is significant [47]. In 2010, the same group reported another interesting site

• -selective Diels–Alder and [2 + 2]-photoaddition reactions between 2 and 2,3-substituted naphthalene 7 mediated by cage host A mentioned above (Figure 2) [48]. Given the reduction of the entropic cost resulting from the effective concentration and preorganization of the guest reactants confined to the

Regioselectivity of the S_EAr-based cyclizations and S_EAr-terminated annulations of 3,5-unsubstituted, 4-substituted indoles

• Jonali Das and
• Sajal Kumar Das

Beilstein J. Org. Chem. 2022, 18, 293–302, doi:10.3762/bjoc.18.33

• catalysis diazo compound 30 delivered 3,4-fused tricyclic indole derivative 32 which underwent spontaneous rearrangement to thermodynamically more stable naphthalene derivative 33 upon standing for a few hours. To the best of our knowledge, this is the only report of catalyst-controlled C3 versus C5

Iridium-catalyzed hydroacylation reactions of C1-substituted oxabenzonorbornadienes with salicylaldehyde: an experimental and computational study

• Angel Ho,
• Austin Pounder,
• Krish Valluru,
• Leanne D. Chen and
• William Tam

Beilstein J. Org. Chem. 2022, 18, 251–261, doi:10.3762/bjoc.18.30

• (EDGs) led to naphthol compounds 9, while electron-withdrawing groups (EWGs) led to the anticipated ring-opened 1,1,2-trisubstituted naphthalene framework 10 [61]. On the other hand, Edmunds and co-workers described a ring-opening reaction of C1-substituted OBDs 5 with arylboronic acids that was

• catalyzed by rhodium/diene to afford the 1,2,4-trisubstituted naphthalene framework 8 with complete regio- and stereocontrol (Scheme 1) [62][63]. In 2015, the Nishimura group reported the first iridium-catalyzed addition of salicylaldehydes 14 to bicyclic alkenes 11 (Scheme 1) [64]. Although a variety of

Trichloroacetic acid fueled practical amine purifications

• Aleena Thomas,
• Baptiste Gasch,
• Enzo Olivieri and
• Adrien Quintard

Beilstein J. Org. Chem. 2022, 18, 225–231, doi:10.3762/bjoc.18.26

• feasibility of a TCA-induced amine purification, we first focused on the study of the different parameters crucial for such a process. For such purpose, we initially studied the purification of a model 1:1 mixture of dicyclohexylamine and naphthalene (Table 1). Gratifyingly, adding 3 equivalents of TCA to

• this mixture dissolved in EtOAc, precipitation of the amine salt enabled the removal of naphthalene in the solvent. Beside the choice of the solvent for the crystallization which strongly depends on the solubility of the protonated amine salts involved, we first focused on the optimization of the

• potential of this system. In order to highlight the interest of this technique and its broad applicability, dicyclohexylamine could be purified from various mixtures containing 1 equivalent of structurally different impurities (Table 2). Aside from naphthalene (Table 2, entry 1), dicyclohexylamine could be

Multi-faceted reactivity of N-fluorobenzenesulfonimide (NFSI) under mechanochemical conditions: fluorination, fluorodemethylation, sulfonylation, and amidation reactions

• José G. Hernández,
• Karen J. Ardila-Fierro,
• Dajana Barišić and
• Hervé Geneste

Beilstein J. Org. Chem. 2022, 18, 182–189, doi:10.3762/bjoc.18.20

• milling (Figure 1b and Figure S5 in Supporting Information File 1). Other substrates such as naphthalene and N-Boc-aniline proved unreactive under the milling conditions with NFSI. However, the more activated arene 2-naphthol underwent double fluorination affording 1,1-difluoronaphthalen-2(1H)-one as the

1,2-Naphthoquinone-4-sulfonic acid salts in organic synthesis

• Ruan Carlos B. Ribeiro,
• Patricia G. Ferreira,
• Amanda de A. Borges,
• Luana da S. M. Forezi,
• Fernando de Carvalho da Silva and
• Vitor F. Ferreira

Beilstein J. Org. Chem. 2022, 18, 53–69, doi:10.3762/bjoc.18.5

• colored product and determine its concentration by a spectrophotometric method, is the most convenient, simple, and inexpensive method for analytical work. Hiyama [53] noted that little is known about the biological activities of sulfonic naphthalene derivatives, despite being important intermediates for

• the synthesis of dyes. Then, he prepared several naphthalene sulfonic derivatives and tested them for their effects on bacteria and viruses, but none of the compounds presented important activity. Hashimoto and co-workers [54] were the first to apply β-NQSNa for the qualitative analysis of

Recent advances in the asymmetric phosphoric acid-catalyzed synthesis of axially chiral compounds

• Alemayehu Gashaw Woldegiorgis and
• Xufeng Lin

Beilstein J. Org. Chem. 2021, 17, 2729–2764, doi:10.3762/bjoc.17.185

• high loading of 20 mol % CPA 18 with a 1-pyrenyl group at the 6,6’-position of the spiro backbone was preferred as the best catalyst for this transformation. Encouragingly, the double atroposelective C–H amination reaction took place and afforded the desired 1,5-dicarbazole naphthalene derivative 63 in

• context, Bai and co-workers (2019) developed the direct intermolecular enantioselective C–H amination of N-aryl-2-naphthylamines 92 with azodicarboxylates 93 to prepare N–C atropisomers of nonbiaryl naphthalene-1,2-diamine 94. In the presence of chiral phosphoric acids (CPA 15), the desired product 94 was

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

• vinylindoline derivatives 125 was achieved by utilizing chiral ligands like chiral binaphane (Scheme 37) [91]. They had observed that the formation of six- and seven-membered rings required elevated temperatures. Subsequently, the same group studied the cyclization of arylene 126 to furnish naphthalene

Chemical syntheses and salient features of azulene-containing homo- and copolymers

• Vijayendra S. Shetti

Beilstein J. Org. Chem. 2021, 17, 2164–2185, doi:10.3762/bjoc.17.139

• , anti-Kasha photophysics, and a small HOMO–LUMO gap when compared to its isomer, naphthalene. These properties make azulene-containing polymers an intriguing entity in the field of functional polymers, especially for organic electronic applications like organic field-effect transistors (OFET) and

• ). The striking feature of azulene is its permanent dipole moment (1.08 D) and blue color unlike its colorless isomer naphthalene [4]. Azulene possesses an unequal distribution of electron density between its highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO

• ) resulting in a relatively small electron repulsion energy in the first singlet excited state and thus, a small HOMO–LUMO (S0–S1) gap compared to naphthalene. The large energy gap between its S2 and S1 states (up to 15000 cm−1) makes internal conversion less probable, making azulene emit from the S2 state

Recent advances in the syntheses of anthracene derivatives

• Giovanni S. Baviera and
• Paulo M. Donate

Beilstein J. Org. Chem. 2021, 17, 2028–2050, doi:10.3762/bjoc.17.131

• -bromonaphthoquinone (140) reacted with vinylacetic acid to afford the allylated compound 141. Then, reduction of 141 and sequential O-methyl-protection furnished naphthalene 142. A Suzuki–Miyaura coupling reaction between 142 and boronic acids afforded 2-naphthylbenzaldehydes 143, which were further subjected to a

• -phenanthrene derivatives 152, also in excellent yields (91–98%) [68]. In 2015, Gribble et al. published a new method to synthesize dibenzo[a,c]anthracene (158) based on a triple benzannulation of naphthalene derivative 153 via a 1,3,6-naphthotriyne synthetic equivalent 155 (Scheme 35) [69]. First, reaction of

• brominated naphthalene 153 with PhLi yielded compound 154, which collapsed to naphthotriyne 155 at elevated temperatures. Sequential addition of furan generated the trisadduct 156. Then, dibenz[a,c]anthracene 158 was obtained in good yield (86%) in two steps by hydrogenation of 156 and further dehydration of

Natural products in the predatory defence of the filamentous fungal pathogen Aspergillus fumigatus

• Jana M. Boysen,
• Nauman Saeed and
• Falk Hillmann

Beilstein J. Org. Chem. 2021, 17, 1814–1827, doi:10.3762/bjoc.17.124

• more likely to survive internalization by lung epithelial cells [147][154][155]. Although DHN-melanin is generally associated with immune evasion it was recently found to be recognized in higher animals via the C-type lectin receptor (MelLec) which interacts with the naphthalene-diol domain of DHN

Development of N-F fluorinating agents and their fluorinations: Historical perspective

• Teruo Umemoto,
• Yuhao Yang and
• Gerald B. Hammond

Beilstein J. Org. Chem. 2021, 17, 1752–1813, doi:10.3762/bjoc.17.123

• aromatics such as phenol, cresol, and naphthalene were fluorinated in chloroform at 22 °C (Scheme 18). The N-F imide reagent 7-1a fluorinated the sodium salt of diethyl 1-methylmalonate at −10 °C to give the corresponding fluoro product in high yield (96%). Later (1991 and 1992), the same laboratory

Volatile emission and biosynthesis in endophytic fungi colonizing black poplar leaves

• Christin Walther,
• Pamela Baumann,
• Katrin Luck,
• Beate Rothe,
• Peter H. W. Biedermann,
• Jonathan Gershenzon,
• Tobias G. Köllner and
• Sybille B. Unsicker

Beilstein J. Org. Chem. 2021, 17, 1698–1711, doi:10.3762/bjoc.17.118

• ]. Endophytic fungi themselves can produce VOCs. Currently, around 300 fungal VOCs have been characterized, including aliphatic alcohols, ketones, aldehydes, acids and esters, terpenoids, benzenoids, naphthalene derivatives, and cycloalkanes [25][26][27]. Endophytic fungal VOCs are frequently described to

• Muscodor vitigenus and characterized the volatile blend in culture [32]. Naphthalene, an insect deterrent that is used, e.g., in mothballs [33], was the most dominant compound in the fungal volatile blend and showed a repellent effect on the wheat stem sawfly Cephus cinctus in a Y-tube olfactometer