Photochemically assisted synthesis of phenacenes fluorinated at the terminal benzene rings and their electronic spectra

• Yuuki Ishii,
• Minoru Yamaji,
• Fumito Tani,
• Kenta Goto,
• Yoshihiro Kubozono and
• Hideki Okamoto

Beilstein J. Org. Chem. 2025, 21, 670–679, doi:10.3762/bjoc.21.53

• 5). The homologous chrysenecarbaldehyde 13 was obtained starting from aldehyde 4 via the same two-step procedure in a 39% yield from 5. Bromophenanthrene derivative 15 was prepared by Wittig reaction between compounds 5 and 7 followed by Mallory photoreaction in a 60% yield from 5. The target

• compounds, F8PIC and F8FUL, were obtained through the Wittig-reaction and Mallory-photoreaction sequence (Scheme 2). Thus, reactions between phosphonium salt 5 and specific aldehydes, 10 and 13, followed by photolysis in the presence of I2 and O2, respectively, afforded F8PIC (57%) and F8FUL (52%). F87PHEN

Total synthesis of (±)-simonsol C using dearomatization as key reaction under acidic conditions

• Xiao-Yang Bi,
• Xiao-Shuai Yang,
• Shan-Shan Chen,
• Jia-Jun Sui,
• Zhao-Nan Cai,
• Yong-Ming Chuan and
• Hong-Bo Qin

Beilstein J. Org. Chem. 2025, 21, 601–606, doi:10.3762/bjoc.21.47

• scaffold of simonsol C, utilizing an alkaline dearomatization as the key reaction, followed by a functional-group-selective Wittig reaction and concurrent oxy-Michael addition [6]. A bromophenol acetal was used in the intramolecular alkylative dearomatization, which was first reported by Magnus et al. [8

New tandem Ugi/intramolecular Diels–Alder reaction based on vinylfuran and 1,3-butadienylfuran derivatives

• Yuriy I. Horak,
• Roman Z. Lytvyn,
• Andrii R. Vakhula,
• Yuriy V. Homza,
• Nazariy T. Pokhodylo and
• Mykola D. Obushak

Beilstein J. Org. Chem. 2025, 21, 444–450, doi:10.3762/bjoc.21.31

• , form heterolignans, which are synthetic derivatives of naturally occurring lignans [22][23][24][25]. This has gained significant attention in drug discovery [26]. Several synthetic routes, such as tandem Pummerer/Diels–Alder or Wittig/Diels–Alder approaches, have been developed for heterolignan

Multicomponent reactions driving the discovery and optimization of agents targeting central nervous system pathologies

• Lucía Campos-Prieto,
• Aitor García-Rey,
• Eddy Sotelo and
• Ana Mallo-Abreu

Beilstein J. Org. Chem. 2024, 20, 3151–3173, doi:10.3762/bjoc.20.261

• post-modification reactions. Examples of these reactions include the Ugi/Dieckmann reactions, Ugi/Robinson–Gabriel reactions, Ugi/Buchwald–Hartwig reactions, Ugi reaction followed by a catalytic aza-Wittig cyclization, Ugi reaction followed by SNAr strategy, Ugi/Heck reactions, Ugi/Huisgen

• -carboxamide-1,4-benzodiazepin-5-ones when enantiopure (S)-(−)-α-methylbenzylamine and arylglyoxals were used. Thus, a reversal of diastereoselectivity was observed depending on the cyclization methodology employed, the reduction of a nitro group or the Staudinger/aza-Wittig on azide derivatives. This

Synthesis of tricarbonylated propargylamine and conversion to 2,5-disubstituted oxazole-4-carboxylates

• Kento Iwai,
• Akari Hikasa,
• Kotaro Yoshioka,
• Shinki Tani,
• Kazuto Umezu and
• Nagatoshi Nishiwaki

Beilstein J. Org. Chem. 2024, 20, 2827–2833, doi:10.3762/bjoc.20.238

• esters and N-acyl groups is limited to acetyl, benzoyl, and alkoxycarbonyl groups [15]. Conversely, NAIs derived from α-oxomalonic acid diester are more versatile. Nagao et al. prepared NAI 2 through the aza-Wittig reaction of diethyl mesoxalate (DEMO, diethyl α-oxomalonate). However, only the N-acetyl

The scent gland composition of the Mangshan pit viper, Protobothrops mangshanensis

• Jonas Holste,
• Paul Weldon,
• Donald Boyer and
• Stefan Schulz

Beilstein J. Org. Chem. 2024, 20, 2644–2654, doi:10.3762/bjoc.20.222

• ) starting from the oxoester 3, which is conveniently available from propenylpiperidine (2) [27] and methyl acrylate [28]. The Wittig reagent 1-methylheptyltriphenylphosphonium iodide (5) was prepared by methylation of the Wittig salt of heptyl iodide (4). A Wittig reaction with 3 afforded an E/Z mixture of

Harnessing the versatility of hydrazones through electrosynthetic oxidative transformations

• Aurélie Claraz

Beilstein J. Org. Chem. 2024, 20, 1988–2004, doi:10.3762/bjoc.20.175

• Wittig, Julia, Peterson and Tebbe-type reactions, the group of Lambert et al. implemented an elegant electrophotocatalytic carbonyl-olefin cross-coupling in an undivided cell equipped with a carbon felt anode and a platinum cathode in the presence of their own trisaminocyclopropenium cationic

Harnessing unprotected deactivated amines and arylglyoxals in the Ugi reaction for the synthesis of fused complex nitrogen heterocycles

• Javier Gómez-Ayuso,
• Pablo Pertejo,
• Tomás Hermosilla,
• Israel Carreira-Barral,
• Roberto Quesada and
• María García-Valverde

Beilstein J. Org. Chem. 2024, 20, 1758–1766, doi:10.3762/bjoc.20.154

• with a reduced reactivity in the synthesis of 3H-benzo[e][1,4]diazepin-5-ones, heterocycles previously synthesized by our research group through Ugi/Staudinger/aza-Wittig and Ugi/reduction/cyclization sequences, using 2-azidobenzoic [20] and 2-nitrobenzoic [21] acids, respectively. The first

• methodology has several drawbacks, as the need to synthesise the 2-azidobenzoic acid from anthranilic acid and sodium azide, the requirement of anhydrous conditions to perform the Staudinger/aza-Wittig sequence or the generation of large quantities of triphenylphosphine oxide which needs to be removed by

• reaction took place with a α,3-like relative configuration on the major diastereomer, similar to that obtained for the Ugi/Staudinger/aza-Wittig sequence and complementary to that observed for the Ugi/reduction/cyclization sequence (see Supporting Information File 1, Figure S2). With the aim of building

One-pot Ugi-azide and Heck reactions for the synthesis of heterocyclic systems containing tetrazole and 1,2,3,4-tetrahydroisoquinoline

• Jiawei Niu,
• Yuhui Wang,
• Shenghu Yan,
• Yue Zhang,
• Xiaoming Ma,
• Qiang Zhang and
• Wei Zhang

Beilstein J. Org. Chem. 2024, 20, 912–920, doi:10.3762/bjoc.20.81

• oxidative cycloisomerization reactions for the synthesis of 2-tetrazolyl-substituted 3-acylpyrroles (Scheme 2C) [42]. The Ding group also reported sequential Ugi-azide/Staudinger/aza-Wittig/addition/Ag-catalyzed cyclization reactions for obtaining 12-tetrazolyl-substituted (E)-5H-quinazolino[3,2-a

(Bio)isosteres of ortho- and meta-substituted benzenes

• H. Erik Diepers and
• Johannes C. L. Walker

Beilstein J. Org. Chem. 2024, 20, 859–890, doi:10.3762/bjoc.20.78

• . Fessard, Salomé and co-workers used this approach to synthesise a small collection of 2-oxo-BCHs including 42 and 44 (Scheme 4A) [40]. These could then be used as precursors for ortho-benzene isosteric 1,2-BCHs (Scheme 4B) [40]. Carbonyl reduction of 42a yielded alcohol (±)-45a. From 42b, Wittig

• undergo chemical transformations in their synthesis of ketoprofen bioisostere 189 (Scheme 18B) [72]. 1,3-Cuneane 186 bearing two electron-withdrawing groups was accessible by oxidation of 1,3-cuneane 185a. The 1,3-cuneane scaffold was stable to Wittig olefination and Weinreb ester formation (to 187

Decarboxylative 1,3-dipolar cycloaddition of amino acids for the synthesis of heterocyclic compounds

• Xiaofeng Zhang,
• Xiaoming Ma and
• Wei Zhang

Beilstein J. Org. Chem. 2023, 19, 1677–1693, doi:10.3762/bjoc.19.123

• developed a 2-azidobenzladehyde-based reaction sequence including a one-pot [3 + 2] cycloaddition, N-acylation and Staudinger/aza-Wittig reactions for the construction of pyrroloquinazolines and pyrrolobenzodiazepines [73]. The AcOH-catalyzed reaction of 2-azidobenzaldehydes, α-substituted amino acids and

• maleimides in MeCN at 110 °C for 6 h afforded the corresponding monocycloaddition compounds followed by acylation to yield intermediates 22. The subsequent sequential Staudinger/aza-Wittig reaction of intermediates 22 gave products 23a–g in 48–75% yields with 5:1 to 6:1 dr (Scheme 14). This one-pot reaction

First synthesis of acylated nitrocyclopropanes

• Kento Iwai,
• Rikiya Kamidate,
• Khimiya Wada,
• Haruyasu Asahara and
• Nagatoshi Nishiwaki

Beilstein J. Org. Chem. 2023, 19, 892–900, doi:10.3762/bjoc.19.67

• through an intramolecular aza-Wittig reaction, yielding cyclopropane-fused 2-quinolones [2]. A nitro group not only activates substrates and stabilizes the α-anion as an electron-withdrawing group but also acts as a nucleophile, electrophile, and leaving group, exhibiting diverse reactivities [3]. For

Facile access to 3-sulfonylquinolines via Knoevenagel condensation/aza-Wittig reaction cascade involving ortho-azidobenzaldehydes and β-ketosulfonamides and sulfones

• Ksenia Malkova,
• Andrey Bubyrev,
• Stanislav Kalinin and
• Dmitry Dar’in

Beilstein J. Org. Chem. 2023, 19, 800–807, doi:10.3762/bjoc.19.60

• have developed a new convenient protocol for the synthesis of 3-sulfonyl-substituted quinolines (sulfonamides and sulfones). The approach is based on a Knoevenagel condensation/aza-Wittig reaction cascade involving o-azidobenzaldehydes and ketosulfonamides or ketosulfones as key building blocks. The

• protocol is appropriate for both ketosulfonyl reagents and α-sulfonyl-substituted alkyl acetates providing the target quinoline derivatives in good to excellent yields. Keywords: aza-Wittig reaction; azides; cyclocondensation; quinolones; sulfonamides; Introduction The quinoline scaffold has a wide

• , the method for the synthesis of 3-acyl-substituted quinolines from o-azidobenzaldehydes and 1,3-dicarbonyl compounds was reported [70][71] (Figure 2a). A combination of Knoevenagel condensation and aza-Wittig reaction allowed to build up target products in high yields. In case of [70], the procedure

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

• -pyridobenzazepines 60b via cyclisation of 2,2'-dihalostilbene analogue 58 through a Pd-catalysed double Buchwald–Hartwig amination. The stilbene analogues 58 were prepared by a Wittig reaction with reported yields of the desired Z-isomer around 55%. The amination step was performed on a series of primary alkylamines

• the synthesis of intermediate stilbenes 61 by Wittig coupling. The authors elected to use a Pd2dba3/DPEphos (L4)/Cs2CO3 system (dba = dibenzylideneacetone; DPEphos = bis[(2-diphenylphosphino)phenyl] ether) in toluene after catalyst and ligand screening. Cyclisation of several substituted 2,2

• ]oxepine derivatives 101 (Scheme 21). Lin et al. [62] used copper-catalysed coupling in their total synthesis of bulbophylol-B (105), a substituted dihydrobenzo[b,f]oxepine. The authors synthesised an intermediate stilbene via Wittig reaction, followed by hydrogenation to give dihydrostilbene 104, which

Combretastatins D series and analogues: from isolation, synthetic challenges and biological activities

• Jorge de Lima Neto and
• Paulo Henrique Menezes

Beilstein J. Org. Chem. 2023, 19, 399–427, doi:10.3762/bjoc.19.31

• only be favorable after the macrolactonization step. The authors used a convergent route for the formal synthesis of 2. Reaction of 4-bromobenzaldehyde (52) with a commercially available stabilized Wittig reagent led to the formation of the corresponding ester 53. Further reduction of the carbonyl

• convergent route by which it was possible to reach both, compound 2 and 1. Initially, the authors prepared the protected alcohol 66 from aldehyde 52 in a linear sequence (Scheme 12). In parallel, the monobenzylation of 3,4-dihydroxybenzaldehyde (67), followed by chain elongation using the Wittig reaction

• Wittig reaction led to the α,β-unsaturated ester 87, which was subjected to a hydrogenation reaction in the presence of metallic magnesium, leading to the formation of alkyne 88. The cis-alkene was selectively obtained using the Lindlar catalyst. Finally, hydrolysis of the ester led to the formation of

Identification and determination of the absolute configuration of amorph-4-en-10β-ol, a cadinol-type sesquiterpene from the scent glands of the African reed frog Hyperolius cinnamomeoventris

• Angelique Ladwig,
• Markus Kroll and
• Stefan Schulz

Beilstein J. Org. Chem. 2023, 19, 167–175, doi:10.3762/bjoc.19.16

• in a Michael addition with methyl acrylate, affording aldehyde 4 (Scheme 1). Instead of the original Wittig reaction [13], a Horner–Wadsworth–Emmons reaction using diethyl (2-methylallyl)phosphonate and BuLi led to a higher yield and formation of the pure (E)-isomer 5. The required phosphonate was

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

• ]) are linear syntheses involving a great number of steps and purifications as well as cryogenic temperatures. Moreover, the introduction of the C=C unsaturation is achieved via a Wittig reaction or a Pd-catalyzed Sonogashira cross-coupling followed by a reduction by a borane reagent, methods which lead

Total synthesis of grayanane natural products

• Nicolas Fay,
• Rémi Blieck,
• Cyrille Kouklovsky and
• Aurélien de la Torre

Beilstein J. Org. Chem. 2022, 18, 1707–1719, doi:10.3762/bjoc.18.181

• , protection of the secondary alcohol as a benzyl ether, oxidation of the sulfur and Pummerer rearrangement (Scheme 3). A Wittig reaction gave compounds 8, as a 10:1 separable diastereomeric mixture. A diastereoselective Diels–Alder cycloaddition followed by oxidation of the resulting epimeric mixture gave

• hydrolysis, esterification, and Jones oxidation, affording intermediate 14 with a good 79% yield over 4 steps. Next, the methyl ketone was converted to an enol triflate, and then coupled with Li2CuCN(CH2SPh)2. A reduction of the ester with DIBAL, followed by Dess–Martin oxidation and Wittig reaction lead to

Solid-phase total synthesis and structural confirmation of antimicrobial longicatenamide A

• Takumi Matsumoto,
• Takefumi Kuranaga,
• Yuto Taniguchi,
• Weicheng Wang and
• Hideaki Kakeya

Beilstein J. Org. Chem. 2022, 18, 1560–1566, doi:10.3762/bjoc.18.166

• unavailable building blocks 7 and 10 were chemically constructed from readily available starting materials. The synthesis of building block 10 commenced with the synthesis of compound 15 through Wittig reaction of Garner’s aldehyde (13) [16], which was readily obtained from tert-butyloxycarbonyl (Boc

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

• -substitution. Subsequent transesterification gave the α-ketoester 75, which was used in a Wittig reaction. The undesired Z-configured double bond was isomerized to the E-alkene and final hydrogenation delivered corynoxine (76). (+)-Gracilamine The Mannich reaction was also used by Nagasawa et al. as a key step

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

• (trimethylsilanyl)diseleno[2,3-b:3′,2′-d]thiophene ((TMS)2-bb-DST), and 2,5-di(trimethylsilanyl)diseleno[2,3-b:3′,2′-d] selenophene ((TMS)2-bb-DSS) were used as starting materials to synthesize three S-shaped double helicenes (i.e., DH-1, DH-2, and DH-3) through monobromination, formylation, the Wittig reaction

• sulfur atoms on the same side is defined as bb by us. The double Wittig reaction of 4a and 4b with 1,3-phenyldimethyltriphenylphosphonium bromide afforded compounds 5a and 5b with yields of 46% and 64%, respectively. After the double Wittig reaction of 4c we obtained a mixture of cis and trans isomers of

New efficient synthesis of polysubstituted 3,4-dihydroquinazolines and 4H-3,1-benzothiazines through a Passerini/Staudinger/aza-Wittig/addition/nucleophilic substitution sequence

• Long Zhao,
• Mao-Lin Yang,
• Min Liu and
• Ming-Wu Ding

Beilstein J. Org. Chem. 2022, 18, 286–292, doi:10.3762/bjoc.18.32

• Abstract A new efficient synthesis of polysubstituted 3,4-dihydroquinazolines and 4H-3,1-benzothiazines via sequential Passerini/Staudinger/aza-Wittig/addition/nucleophilic substitution reaction has been developed. The three-component Passerini reactions of 2-azidobenzaldehydes 1, benzoic acid (2), and

• isocyanides 3 produced the azide intermediates 4, which were treated sequentially with triphenylphosphine, isocyanates (or CS2), and secondary amines to give polysubstituted 3,4-dihydroquinazolines 8 and 4H-3,1-benzothiazines 11 in good overall yields through consecutive Passerini/Staudinger/aza-Wittig

• /addition/nucleophilic substitution reactions. Keywords: aza-Wittig reaction; 3,4-dihydroquinazoline; 4H-3,1-benzothiazine; nucleophilic substitution; Passerini reaction; Staudinger reaction; Introduction The chemistry of 3,4-dihydroquinazolines and 4H-3,1-benzothiazines is of constant interest owing to

Synthesis and late stage modifications of Cyl derivatives

• Phil Servatius and
• Uli Kazmaier

Beilstein J. Org. Chem. 2022, 18, 174–181, doi:10.3762/bjoc.18.19

• NMR spectra. The solubility issues forced us to investigate also other modification protocols. Thus, macrocycle 11 was subjected to an ozonolysis with subsequent Wittig reaction in a one-pot manner (Scheme 4). Performing the ozonolysis in presence of pyridine led to immediate reduction of the primary

• ozonide formed during the reaction [57]. Consequently, no PPh3 or Me2S was required to obtain the crude aldehyde. Subsequent addition of a Wittig ylide gave access to a cyclopeptide with an α,β-unsaturated ester side chain as a (E/Z) mixture. Unfortunately, this compound contained triphenylphosphine oxide

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

• transformations. Organometallics are the most commonly used catalysts to promote C–C bond formation. In addition, other so-called classical reactions are also widely used, such as Friedel–Crafts alkylation and acylation, Wittig and Horner–Emmons reactions, carbonyl addition/substitution, α-alkylation, aldol

The ethoxycarbonyl group as both activating and protective group in N-acyl-Pictet–Spengler reactions using methoxystyrenes. A short approach to racemic 1-benzyltetrahydroisoquinoline alkaloids

• Marco Keller,
• Karl Sauvageot-Witzku,
• Franz Geisslinger,
• Nicole Urban,
• Michael Schaefer,
• Karin Bartel and
• Franz Bracher

Beilstein J. Org. Chem. 2021, 17, 2716–2725, doi:10.3762/bjoc.17.183

• ethyl chloroformate/Et3N, followed by Wittig olefination with an ylide generated from (methoxymethyl)triphenylphosphonium chloride and LDA to give the enol ethers as E/Z mixtures. N-Phenethyl carbamates were obtained from benzaldehydes via Henry reaction with nitromethane, followed by zinc dust