Strategies in the synthesis of dibenzo[b,f]heteropines

• David I. H. Maier,
• Barend C. B. Bezuidenhoudt and
• Charlene Marais

Beilstein J. Org. Chem. 2023, 19, 700–718, doi:10.3762/bjoc.19.51

• from 2-bromostyrene (116) via halogen–lithium exchange and quenching with the appropriate heteroatom source (SiR2Cl2, SnMe2Cl2, GeR2Cl2, BBr3). P-Tethered dienes were synthesised via quenching of a 2-vinylphenyl Grignard reagent with phenylphosphonic dichloride (PhPOCl2). O-Tethered dienes were

• authors brominated 2a in acetic acid, resulting in a tetrabrominated intermediate 154 in excellent yield (90%). Selective lithium–halogen exchange and reaction with a chlorophosphine, followed by debromination with BuLi/MeOH, gave the desired bisphosphine 155 in good yield (Scheme 36). Conclusion The

Enolates ambushed – asymmetric tandem conjugate addition and subsequent enolate trapping with conventional and less traditional electrophiles

• Péter Kisszékelyi and
• Radovan Šebesta

Beilstein J. Org. Chem. 2023, 19, 593–634, doi:10.3762/bjoc.19.44

• trapping by adding MeLi (1.05 equiv), which indeed led to a significant increase in yield and selectivity due to the high reactivity of the lithium dialkyl zincate enolate. Various 1,3-diketones 39 were prepared using this method with good yields and excellent enantioselectivities while only the trans

• desymmetrization step during which the chiral enolate attacks (Si-face) the prochiral cyclohexadienone ring via a chair-like transition state. The reaction requires an excess amount of base, resulting in the formation of a more favorable lithium enolate. Subsequent oxidation of the boronates gave the corresponding

Strategies to access the [5-8] bicyclic core encountered in the sesquiterpene, diterpene and sesterterpene series

• Cécile Alleman,
• Charlène Gadais,
• Laurent Legentil and
• François-Hugues Porée

Beilstein J. Org. Chem. 2023, 19, 245–281, doi:10.3762/bjoc.19.23

• cyclopropane 185 was performed with lithium in liquid ammonia in order to introduce the angular methyl group. In the same time, the ketone was reduced into an alcohol, which one was submitted to Barton deoxygenation. The alkene side chain underwent a metathesis reaction with methyl methacrylate to introduce an

Friedel–Crafts acylation of benzene derivatives in tunable aryl alkyl ionic liquids (TAAILs)

• Swantje Lerch,
• Stefan Fritsch and
• Thomas Strassner

Beilstein J. Org. Chem. 2023, 19, 212–216, doi:10.3762/bjoc.19.20

• lithium bis(trifluoromethylsulfonyl)imide (LiNTf2). All reactions are generally tolerant towards different aryl substitutions, substitution patterns, alkyl chain lengths and can be carried out in a multigram scale [57]. The acylation of the electron-rich benzene derivative anisole with acetic anhydride

Germacrene B – a central intermediate in sesquiterpene biosynthesis

• Houchao Xu and
• Jeroen S. Dickschat

Beilstein J. Org. Chem. 2023, 19, 186–203, doi:10.3762/bjoc.19.18

• -workers [19], through a sequence of reduction to the alcohol, acetylation and reduction with lithium in ammonia (Scheme 3A) [20], and its structure was unambiguously assigned by X-ray crystallography of a silver nitrate adduct [21]. From natural sources, the compound was first obtained from Humulus

Synthetic study toward tridachiapyrone B

• Morgan Cormier,
• Florian Hernvann and
• Michaël De Paolis

Beilstein J. Org. Chem. 2022, 18, 1741–1748, doi:10.3762/bjoc.18.183

• chiral tetrahydrofuran (Scheme 1b). To assemble the skeleton of the natural product, we developed a new strategy in which the α,α’-dimethoxy-γ-pyrone motif 2 was first desymmetrized by a sequence encompassing the conjugate addition of 2-lithio-1,3-dithiane, elimination of methoxide lithium, and

• ambitious coupling, however, met a dead-end and a less direct approach was explored. With a more reactive and less hindered nucleophile, we explored the coupling of lithiocyclopentadiene to compound 2. After conjugate addition and elimination of lithium methoxide, the resulting 6a would be deprotonated by

Synthesis of (−)-halichonic acid and (−)-halichonic acid B

• Keith P. Reber and
• Emma L. Niner

Beilstein J. Org. Chem. 2022, 18, 1629–1635, doi:10.3762/bjoc.18.174

• hydrolysis of compounds 8 and 9 to form the corresponding amino acids. Thus, treating bicycle 8 with aqueous lithium hydroxide resulted in hydrolysis of the ethyl ester, and subsequent neutralization with pH 7 phosphate buffer afforded halichonic acid ((−)-1) in 88% yield after purification by column

Synthetic study toward the diterpenoid aberrarone

• Liang Shi,
• Zhiyu Gao,
• Yiqing Li,
• Yuanhao Dai,
• Yu Liu,
• Lili Shi and
• Hong-Dong Hao

Beilstein J. Org. Chem. 2022, 18, 1625–1628, doi:10.3762/bjoc.18.173

• through the corresponding lithium enolate occurred from the convex face of the bicyclic ring system [37]. After these two continuous stereocenters were successfully installed, the expected challenging all-carbon quaternary center at C1 was constructed utilizing the Nagata reagent (Et2AlCN). By using this

Preparation of β-cyclodextrin-based dimers with selectively methylated rims and their use for solubilization of tetracene

• Konstantin Lebedinskiy,
• Volodymyr Lobaz and
• Jindřich Jindřich

Beilstein J. Org. Chem. 2022, 18, 1596–1606, doi:10.3762/bjoc.18.170

• deacetylation of 8, proved to be not reactive enough to complete the reaction in 24 h under the conditions used to prepare the dimer 5. The prolongation of the reaction time increased the yield slightly, but it was still too low (17%). To improve the yield, we used lithium iodide and increased the temperature

Synthesis of the biologically important dideuterium-labelled adenosine triphosphate analogue ApppI(d₂)

• Petri A. Turhanen

Beilstein J. Org. Chem. 2022, 18, 1466–1470, doi:10.3762/bjoc.18.153

• -enoic acid (2) was then reduced to 3-methylbut-3-en-1,1-d2-1-ol (3) with lithium aluminium deuteride, followed by tosylation with tosyl chloride. Tosylated 3-methylbut-3-en-1,1-d2-1-ol 4 was then treated with ATP TBA salt in acetonitrile at 45 °C for 55 h to give the target product ApppI(d2) (Scheme 1

Preparation of an advanced intermediate for the synthesis of leustroducsins and phoslactomycins by heterocycloaddition

• Anaïs Rousseau,
• Guillaume Vincent and
• Cyrille Kouklovsky

Beilstein J. Org. Chem. 2022, 18, 1385–1395, doi:10.3762/bjoc.18.143

• [30][31]. However, condensation of the corresponding lithium acetylide to the ketone 11b gave modest and non-reproducible yields of the desired product 22 (Scheme 7, Table 1). The configuration of the newly created stereogenic center was undetermined. These experiments showed the necessity to perform

Ionic multiresonant thermally activated delayed fluorescence emitters for light emitting electrochemical cells

• Merve Karaman,
• Abhishek Kumar Gupta,
• Subeesh Madayanad Suresh,
• Tomas Matulaitis,
• Lorenzo Mardegan,
• Daniel Tordera,
• Henk J. Bolink,
• Sen Wu,
• Stuart Warriner,
• Ifor D. Samuel and
• Eli Zysman-Colman

Beilstein J. Org. Chem. 2022, 18, 1311–1321, doi:10.3762/bjoc.18.136

• operation. To solve this, we fabricated devices adding an ionic liquid (lithium hexafluorophosphate (LiPF6) or 1-butyl-3-methylimidazolium hexafluorophosphate (BMIM:PF6) in a 4 to 1 molar ratio) and, in some cases, an electrolyte matrix (PEO (polyethylene oxide)), to improve the ionic mobility on the active

Modular synthesis of 2-furyl carbinols from 3-benzyldimethylsilylfurfural platforms relying on oxygen-assisted C–Si bond functionalization

• Sebastien Curpanen,
• Per Reichert,
• Gabriele Lupidi,
• Giovanni Poli,
• Julie Oble and
• Alejandro Perez-Luna

Beilstein J. Org. Chem. 2022, 18, 1256–1263, doi:10.3762/bjoc.18.131

• alkoxides We first contemplated the possibility to promote C3–Si bond functionalization through intramolecular activation by alkoxides [15]. It was reported that lithium alkoxides A undergo 1,4-silyl migration (Brook rearrangement) to generate C2-lithiated furans C, which in turn can react in the presence

Vicinal ketoesters – key intermediates in the total synthesis of natural products

• Marc Paul Beller and
• Ulrich Koert

Beilstein J. Org. Chem. 2022, 18, 1236–1248, doi:10.3762/bjoc.18.129

• with Davis’ oxaziridine and subsequent oxidation using Dess–Martin periodinane. Initial attempts for the key step (15 → 16) like a Nozaki–Hiyama–Kishi reaction failed, but lithium–halogen exchange using t-BuLi at low temperatures gave the desired vinyllithium intermediate I which successfully added to

• also be used in photochemical reactions, as shown by Gramain et al. in the synthesis of the pyrrolizidine alkaloid (rac)-isoretronecanol (69, Scheme 11) [26]. A Claisen condensation of the lithium enolate of N-acetylpyrrolidine (66) with diethyl oxalate gave the ketoester 67. Irradiation of compound 67

Electrogenerated base-promoted cyclopropanation using alkyl 2-chloroacetates

• Kouichi Matsumoto,
• Yuta Hayashi,
• Kengo Hamasaki,
• Mizuki Matsuse,
• Hiyono Suzuki,
• Keiji Nishiwaki and
• Norihito Kawashita

Beilstein J. Org. Chem. 2022, 18, 1116–1122, doi:10.3762/bjoc.18.114

• stoichiometric amount of metal lithium was utilized to reduce ethyl 2-bromoacetate to form the corresponding 1,2,3-trisubstituted cyclopropane derivatives (Scheme 1, reaction 3) [12]. The generation of an anionic intermediate was indicated. During our study, we discovered that 1,2,3-trisubstituted cyclopropane

• derivatives could be formed in moderate yields through the electrochemical reduction [13][14][15][16][17][18][19][20][21] of alkyl 2-chloroacetates in a divided cell (Scheme 1, reaction 4). The in Abushanab’s study utilized metal lithium is one of the rarest and most expensive metals. In addition, the

• treatment of metal lithium is difficult and occasionally dangerous, and the reaction also produces the corresponding Li salt as waste [22][23]. In contrast, in this work, we use basic electricity to make the corresponding cyclopropane derivatives. Herein, we would like to report the details of our

Radical cation Diels–Alder reactions of arylidene cycloalkanes

• Kaii Nakayama,
• Hidehiro Kamiya and
• Yohei Okada

Beilstein J. Org. Chem. 2022, 18, 1100–1106, doi:10.3762/bjoc.18.112

• cation cycloadditions using (photo)electrochemical single-electron transfer in lithium perchlorate (LiClO4)/nitromethane (CH3NO2) solution [36][37][38][39][40][41][42][43][44]. During the course of our studies, we found that the TiO2 photoelectrochemical approach was more beneficial than simple

Introducing a new 7-ring fused diindenone-dithieno[3,2-b:2',3'-d]thiophene unit as a promising component for organic semiconductor materials

• Valentin H. K. Fell,
• Joseph Cameron,
• Alexander L. Kanibolotsky,
• Eman J. Hussien and
• Peter J. Skabara

Beilstein J. Org. Chem. 2022, 18, 944–955, doi:10.3762/bjoc.18.94

• using polyphosphoric acid [16] and sulfuric acid failed [42], therefore we tried Friedel–Crafts acylation. For that, 27 was hydrolysed to the corresponding diacid 28 with lithium hydroxide [15]. In a manner similar to [24], firstly, a ‘cold’ Friedel–Crafts acylation in dichloromethane was attempted, in

• chromatography, in a manner similar to a reported procedure [49]. In a manner similar to [40], intermediate 27 was reacted with 32 within a Suzuki–Miyaura coupling to achieve 33 (Scheme 4). Intermediate 33 was then hydrolysed to the diacid 34 with lithium hydroxide [15]. Compound 34 was successfully reacted

• aqueous lithium hydroxide, THF, 4 h, 94% [15]; e) copper powder, quinoline, 230 °C, 1 h, 81% [15]; f) N-bromosuccinimide, CHCl3/glacial acetic acid, 0 °C, 1 h, rt, 1.5 h, 94% [15] ; g) n-BuLi, −90 °C, 20 min, triisopropyl borate, −80 °C, anhydrous THF, rt, overnight, 97% [34]; h) pinacol, toluene, 115 °C

On Reuben G. Jones synthesis of 2-hydroxypyrazines

• Pierre Legrand and
• Yves L. Janin

Beilstein J. Org. Chem. 2022, 18, 935–943, doi:10.3762/bjoc.18.93

• (Table 2, entries 5 and 6 in comparison with entry 2). Trials using ethanol or isopropanol as a solvent (Table 2, entries 7 and 8) were not successful, plausibly because of a precipitation of the reaction medium before the end of the base addition. Trials with lithium or potassium hydroxide (Table 2

Synthetic strategies for the preparation of γ-phostams: 1,2-azaphospholidine 2-oxides and 1,2-azaphospholine 2-oxides

• Jiaxi Xu

Beilstein J. Org. Chem. 2022, 18, 889–915, doi:10.3762/bjoc.18.90

• )(phenyl)phosphinate (53) was reduced with lithium aluminum hydride to 2-aminobenzyl(phenyl)phosphine (57). It was oxidized with sulfur to give zwitterionic 2-aminobenzyl(phenyl)dithiophosphinic acid (58), which underwent thermal elimination of hydrogen sulfide to yield 2-phenyl-1,3-dihydrobenzo[d][1,2

• as starting materials, realizing an unprecedented asymmetric induction in the synthesis of cyclohexadiene-fused γ-phosphinolactams 126–131, through the formation of configurationally stable lithium salts. When aldehydes 125 were applied as electrophiles, three new stereocenters were generated in the

Synthesis of odorants in flow and their applications in perfumery

• Merlin Kleoff,
• Paul Kiler and
• Philipp Heretsch

Beilstein J. Org. Chem. 2022, 18, 754–768, doi:10.3762/bjoc.18.76

• achieved within milliseconds initializing bromine–lithium exchange of bromochloromethane to generate (chloromethyl)lithium. This carbenoid species readily reacts with terpenyl pinacol boronates 17, resulting in the formation of intermediate 18, which undergoes 1,2-anionotropic rearrangement to the

Synthesis of sulfur karrikin bioisosteres as potential neuroprotectives

• Martin Pošta,
• Václav Zima,
• Lenka Poštová Slavětínská,
• Marika Matoušová and
• Petr Beier

Beilstein J. Org. Chem. 2022, 18, 549–554, doi:10.3762/bjoc.18.57

• compounds 8, 20 and 21 albeit in low yields. Due to the extremely low isolated yield of compounds 20 and 21, we looked for an alternative more efficient procedure. In 2008 Sun et al. [32] described a method of karrikin alkylation in position 7 via direct metalation with lithium bis(trimethylsilyl)amide

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

• demethoxycarbonylating annulation of methyl methacrylate (33) with 3-cyanophthalide (32), in the presence of lithium tert-butoxide as catalyst (64% yield) (Scheme 7) [91]. Recently, Dissanayake and co-workers tested the stability of furans to be used as a diene in Diels–Alder reactions for the synthesis of p

• ). The studies showed that the emulsion, prepared by sonication, of an equimolar mixture of lithium perfluorooctane sulfonate (LiFOS) and perfluorohexane (PFH) in aqueous medium resulted in a significant increase of the reaction rate, when compared to other reaction conditions [109]. As an example, using

Ready access to 7,8-dihydroindolo[2,3-d][1]benzazepine-6(5H)-one scaffold and analogues via early-stage Fischer ring-closure reaction

• Irina Kuznetcova,
• Felix Bacher,
• Daniel Vegh,
• Hsiang-Yu Chuang and
• Vladimir B. Arion

Beilstein J. Org. Chem. 2022, 18, 143–151, doi:10.3762/bjoc.18.15

• steps as shown in Scheme 3. First, reduction of commercially available indole-2-carboxylate with lithium aluminum hydride in dry tetrahydrofuran gave (1H-indole-2-yl)methanol (10) in 89% yield. The obtained alcohol was exposed to benzoyl chloride and triethylamine to furnish benzoate 11, which was

• lithium hydroxide monohydrate [29] to give the desired indole-2-acetic acid (14) in 95% yield. The peptide coupling reaction [30] of indole-2-acetic acid (14) and 2-iodoaniline afforded 15 in 23% yield (Scheme 3). Subsequent protection of both the indole and the amide nitrogen with tert-butyloxycarbonyl

A two-phase bromination process using tetraalkylammonium hydroxide for the practical synthesis of α-bromolactones from lactones

• Yuki Yamamoto,
• Akihiro Tabuchi,
• Kazumi Hosono,
• Takanori Ochi,
• Kento Yamazaki,
• Shintaro Kodama,
• Akihiro Nomoto and
• Akiya Ogawa

Beilstein J. Org. Chem. 2021, 17, 2906–2914, doi:10.3762/bjoc.17.198

• -valerolactone (1a), has been limited. The main process for the bromination of δ-valerolactone (1a) was treating the lactone with lithium diisopropylamide (LDA) at −78 °C to first generate the corresponding enolate, trapping it with trimethylsilyl chloride (TMSCl) to form the enol silyl ether, followed by

Effect of a twin-emitter design strategy on a previously reported thermally activated delayed fluorescence organic light-emitting diode

• Ettore Crovini,
• Zhen Zhang,
• Yu Kusakabe,
• Yongxia Ren,
• Yoshimasa Wada,
• Bilal A. Naqvi,
• Prakhar Sahay,
• Tomas Matulaitis,
• Stefan Diesing,
• Ifor D. W. Samuel,
• Wolfgang Brütting,
• Katsuaki Suzuki,
• Hironori Kaji,
• Stefan Bräse and
• Eli Zysman-Colman

Beilstein J. Org. Chem. 2021, 17, 2894–2905, doi:10.3762/bjoc.17.197

• )) (10 nm)/X wt % DICzTRZ or ICzTRZ: CzSi (20 nm)/PPF (2,8-bis(diphenylphosphoryl)dibenzo[b,d]furan) (5 nm)/TPBi (1,3,5-tris(1-phenyl-1H-benzo[d]imidazol-2-yl)benzene) (50 nm)/Liq (lithium quinolin-8-olate) (1 nm)/Al (80 nm), where X is 20 or 30. The PVK layer is applied to facilitate hole injection from