Direct synthesis of acyl fluorides from carboxylic acids using benzothiazolium reagents

• Lilian M. Maas,
• Alex Haswell,
• Rory Hughes and
• Matthew N. Hopkinson

Beilstein J. Org. Chem. 2024, 20, 921–930, doi:10.3762/bjoc.20.82

• fluoride 2, carbonyl sulfide and another fluoride ion. As a result of this pathway, each molecule of the BT-SCF3 reagent can in principle lead to the formation of two molecules of acyl fluoride 2. Indeed, a yield of 2a above 50% was observed during the optimisation studies using 0.5 equiv of BT-SCF3 (Table

A laterally-fused N-heterocyclic carbene framework from polysubstituted aminoimidazo[5,1-b]oxazol-6-ium salts

• Andrew D. Gillie,
• Matthew G. Wakeling,
• Bethan L. Greene,
• Louise Male and
• Paul W. Davies

Beilstein J. Org. Chem. 2024, 20, 621–627, doi:10.3762/bjoc.20.54

• aminide 7 in good yield on a gram scale (Scheme 1b). With the novel 3-aminoimidazo[5,1-b]oxazol-6-ium salt in hand, we examined its use as an NHC precursor for the preparation of late transition metal complexes. Treating compound 9a with triethylamine and either dimethyl sulfide gold(I) chloride or copper

Green and sustainable approaches for the Friedel–Crafts reaction between aldehydes and indoles

• Periklis X. Kolagkis,
• Eirini M. Galathri and
• Christoforos G. Kokotos

Beilstein J. Org. Chem. 2024, 20, 379–426, doi:10.3762/bjoc.20.36

• research group explored the activity of cadmium sulfide (CdS) nanotubes as heterogeneous nanocatalysts for the electrophilic condensation between aldehydes and indoles [106]. The nanorods were obtained with a solvothermal technique, where thiourea and cadmium nitrate were mixed in ethylenediamine for 10

Synthesis of π-conjugated polycyclic compounds by late-stage extrusion of chalcogen fragments

• Aissam Okba,
• Pablo Simón Marqués,
• Kyohei Matsuo,
• Naoki Aratani,
• Hiroko Yamada,
• Gwénaël Rapenne and
• Claire Kammerer

Beilstein J. Org. Chem. 2024, 20, 287–305, doi:10.3762/bjoc.20.30

• sulfide (Na2S). Since the nature of the imide substituents is very important to control the solid state molecular arrangement, the same authors revised their initial synthetic route to allow for a late stage introduction of the imide groups, thus leading to the preparation of a series of variously

• corresponding boronic acid 9 and a Suzuki–Miyaura cross-coupling between 8 and 9 gave rise to dimer 10, followed by the oxidation of both acenaphthene units into 1,8-naphthalic anhydrides. Installation of the thiepine ring was achieved by a double nucleophilic aromatic substitution induced by sodium sulfide

Anion–π catalysis on carbon allotropes

• M. Ángeles Gutiérrez López,
• Mei-Ling Tan,
• Giacomo Renno,
• Augustina Jozeliūnaitė,
• J. Jonathan Nué-Martinez,
• Javier Lopez-Andarias,
• Naomi Sakai and
• Stefan Matile

Beilstein J. Org. Chem. 2023, 19, 1881–1894, doi:10.3762/bjoc.19.140

• monomer 22 much less significantly. With less electron-deficient NDIs carrying two sulfide donors in the core, the catalytic activity of 45 dropped below that of fullerene monomer 22. Oxidation of the sulfide donors into sulfoxide acceptors increased the catalytic activity much less than expected, resting

N-Sulfenylsuccinimide/phthalimide: an alternative sulfenylating reagent in organic transformations

• Fatemeh Doraghi,
• Seyedeh Pegah Aledavoud,
• Mehdi Ghanbarlou,
• Bagher Larijani and
• Mohammad Mahdavi

Beilstein J. Org. Chem. 2023, 19, 1471–1502, doi:10.3762/bjoc.19.106

• sulfide moieties 11 was performed by Fu et al. (Scheme 6) [47]. Iron(III) chloride was used as a catalyst for this coupling reaction without the need of any ligand and additive. Screening for other metal salts, such as Cu(OAc)2, Pd(OAc)2, AgOAc or CuI was not successful, although FeS·7H2O, FeS, Fe2(SO4)3

• , CF3CO2SR, which was produced in the previous step, as a sulfenylating reagent, reacted with I to form the 3,3-bis-sulfide indolenium III. The migration of a sulfide group to the C2-site of indole, generated 2,3-disubstituted indole V. Protonation of V resulted in indolenium intermediate VI. Finally

• sulfide molecules 137 (Scheme 58) [90]. The Lewis basicity nature of PhSePh as a catalyst and the presence of Lewis acid TMSOTf improved the chemical yields. It is interesting to note that the reaction carried out at a lower temperature because of the high reactivity of allene 136. When the reaction was

Cyanothioacetamides as a synthetic platform for the synthesis of aminopyrazole derivatives

• Valeriy O. Filimonov,
• Alexandra I. Topchiy,
• Vladimir G. Ilkin,
• Tetyana V. Beryozkina and
• Vasiliy A. Bakulev

Beilstein J. Org. Chem. 2023, 19, 1191–1197, doi:10.3762/bjoc.19.87

• elimination of hydrogen sulfide (Scheme 2). Thus, we have shown that when 2-cyanothioacetamides 1a–c react with hydrazine hydrate (3a) in ethanol, both groups (thioamide and cyano) interact with hydrazine with the elimination of hydrogen sulfide and the formation of 3,5-diaminopyrazoles 4a–c (Scheme 2). It

Selective and scalable oxygenation of heteroatoms using the elements of nature: air, water, and light

• Damiano Diprima,
• Hannes Gemoets,
• Stefano Bonciolini and
• Koen Van Aken

Beilstein J. Org. Chem. 2023, 19, 1146–1154, doi:10.3762/bjoc.19.82

• originates from water. In this tentative mechanism, the sulfide I forms with water and oxygen a photoactive complex II which is excited at 365 nm towards III. Via single-electron transfer both a radical cation IV and the superoxide V are generated. Subsequently, the sulfide radical cation IV undergoes a

Photoredox catalysis harvesting multiple photon or electrochemical energies

• Mattia Lepori,
• Simon Schmid and
• Joshua P. Barham

Beilstein J. Org. Chem. 2023, 19, 1055–1145, doi:10.3762/bjoc.19.81

• direct application of commercially available potassium (poly)sulfide (K2Sx) with H2O, the top-down generation from elemental sulfur (S8) with sodium tert-butoxide (NaOt-Bu), and the bottom-up generation from lithium sulfide (Li2S) or triisopropylsilanethiol (iPr3SiSH) were all suitable methods of

Eschenmoser coupling reactions starting from primary thioamides. When do they work and when not?

• Lukáš Marek,
• Jiří Váňa,
• Jan Svoboda and
• Jiří Hanusek

Beilstein J. Org. Chem. 2023, 19, 808–819, doi:10.3762/bjoc.19.61

• reaction pathway opens that involves either the E2 or E1cB-like mechanism to give the corresponding nitrile X and thiolate IX, which can be further alkylated with an excess of α-halogen component to give a symmetrical sulfide. Only in very few cases when the starting α-thioiminium salt III contains an

• (Table 3, entries 4–6). The addition of a weak base (KHCO3, entries 2 and 8 in Table 3) causes partial elimination of salt 12a to N-phenyl-2-sulfanyl(phenyl)acetamide whose reaction with 4a gives stable sulfide 14a, together with a minor occurrence of thiazole 13 and thiobenzamide. A somewhat different

• behavior was observed with substrate 4b, where a mixture of thiazole 13, sulfide 14b and thiobenzamide was formed in DMF (Table 3, entries 9 and 10) even without any base. This behavior corresponds to a much worse leaving ability of methylamine (pKa = 10.6) from cyclic intermediate en route to thiazole 13

1,4-Dithianes: attractive C2-building blocks for the synthesis of complex molecular architectures

• Bram Ryckaert,
• Ellen Demeyere,
• Frederick Degroote,
• Hilde Janssens and
• Johan M. Winne

Beilstein J. Org. Chem. 2023, 19, 115–132, doi:10.3762/bjoc.19.12

• 21 cannot be lithiated to give a stable vinyllithium species, and immediately expel a sulfide anion to afford phenylthioacetylene (Scheme 6a) [40], Brandsma showed that the lithiated derivatives of 1,4-dithiin (3) can be generated by ‘ortho-lithiation’-type reactions at −110 °C in THF (Scheme 6d) [41

Organophosphorus chemistry: from model to application

• György Keglevich

Beilstein J. Org. Chem. 2023, 19, 89–90, doi:10.3762/bjoc.19.8

• in organophosphorus chemistry. A series of P-stereogenic chiral thiophosphorus acids, such as a fused 1-hydroxytetrahydrophosphinine 1-sulfide, an oxaphosphinine sulfide analogue, and an azaphosphinine sulfide analogue were synthesized my Montchamp and Winters as potential organocatalysts [4]. The

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

• ]octane CD ring system with the correct configuration. The synthesis started from commercially available (S)-2-((p-toluenesulfonyl)oxy)-1-propanol (6) which was converted to (R)-2-(benzyloxy)propionaldehyde (7) by a sequence involving formation of the a phenyl sulfide through an epoxide intermediate

• the formation of 15. This intermediate was coupled with an (R)-epoxide in presence of s-BuLi, and intermediate 16 with E configuration was then obtained by a (PhS)2-accelerated 1,3-sulfide shift. The A ring was then cyclized by a sequence consisting of protection of the alcohol, oxidative cleavage of

Redox-active molecules as organocatalysts for selective oxidative transformations – an unperceived organocatalysis field

• Elena R. Lopat’eva,
• Igor B. Krylov,
• Dmitry A. Lapshin and
• Alexander O. Terent’ev

Beilstein J. Org. Chem. 2022, 18, 1672–1695, doi:10.3762/bjoc.18.179

• electrophile and the nucleophile with the specific preorganization of the substrates by the catalyst is crucial for high enantioselectivity [67] (as in example A in Scheme 4). However, in example B the transition state without specific interactions between the sulfide and the catalyst is proposed. In this case

• , the acidic and basic sites of the catalyst are suggested to be involved in the activation of only hydrogen peroxide within a well-defined and deep chiral cavity. The enantioselective approach of sulfide to H2O2 is ensured by the sterically demanding structure of the catalyst. It should also be noted

• that hydrogen bonding is considered as one of the key factors determining the selectivity of catalyst-free sulfoxidations [68]. In such reactions, the selectivity of sulfide oxidation by oxone (sulfoxide/sulfone ratio) was controlled by the solvent nature (deeper oxidation was observed in water than in

A new route for the synthesis of 1-deazaguanine and 1-deazahypoxanthine

• Raphael Bereiter,
• Marco Oberlechner and
• Ronald Micura

Beilstein J. Org. Chem. 2022, 18, 1617–1624, doi:10.3762/bjoc.18.172

• . Subsequent reduction with sodium dithionite then afforded triamine 9. Another way comprised the installation of a nitroso group in compound 6 through reaction with in situ-generated nitrous acid giving nitroso compound 8. The subsequent reduction to the corresponding amine with hydrogen sulfide afforded the

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

• for the synthesis of 1,2-azaphospholidine 2-oxides/sulfides and their fused derivatives. The 1,2-azaphospholidine 2-oxide/sulfide derivatives have been prepared by construction of any of their ring bonds. Synthesis via C–N bond formation In 1962, Helferich and Curtius reported the first synthesis of a

• -arylaminopropyl(methyl)phosphinic acids 45 under reduced pressure. The reactions of 1,2-oxaphospholane 2-oxides 47/2-sulfides 50 and anilines 48 generated 1-aryl-2-methyl-1,2-azaphospholidine 2-oxides 49 and 46a as well, while the reaction of 1,2-thiaphospholane 2-sulfide (51) with aniline (48a) gave

• azaphospholidine 2-sulfide 52 in only 21% yield by heating at 200 °C for 60 h (Scheme 8) [28]. In 1982, Collins and co-workers prepared both 1,3-dihydrobenzo[d][1,2]azaphosphole 2-oxides 56 and 2-sulfide 60 through heating zwitterionic 2-aminobenzyl(phenyl)phosphinic acid 54 and 2-aminobenzyl(phenyl

Cathodic generation of reactive (phenylthio)difluoromethyl species and its reactions: mechanistic aspects and synthetic applications

• Sadanobu Iwase,
• Shinsuke Inagi and
• Toshio Fuchigami

Beilstein J. Org. Chem. 2022, 18, 872–880, doi:10.3762/bjoc.18.88

• bromodifluoromethyl phenyl sulfide (1) using o-phthalonitrile as a mediator generated the (phenylthio)difluoromethyl radical, which reacted with α-methylstyrene and 1,1-diphenylethylene to provide the corresponding adducts in moderate and high yields, respectively. In contrast, chemical reduction of 1 with SmI2

• generation of (phenylthio)difluoromethyl reactive species from bromodifluoromethyl phenyl sulfide and their synthetic application as well as mechanistic aspects. Results and Discussion Cathodic reduction of bromodifluoromethyl phenyl sulfide (1) At first, the reduction potential (Epred) of

• bromodifluoromethyl phenyl sulfide (1) was measured by cyclic voltammetry in an anhydrous acetonitrile (MeCN) solution containing Bu4NClO4 (0.1 M) using a platinum electrode. One irreversible reduction peak was observed at −2.4 V vs SSCE at a scan rate of 100 mV/s. Even at a much higher scan rate of 500 mV/s, 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

• closure (Scheme 1). A plausible mechanism for the cyclization of compounds 7 is the Darzens reaction to episulfide, followed by Barton–Kellogg-type reaction with triphenylphosphine and elimination of triphenylphosphine sulfide. Compound 8 showed lower germination activity than KAR1 [22], but achieved IC50

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

• smoothly substituted at the α-position with benzenethiol (4) in the presence of K2CO3 to afford the unsymmetrically functionalized sulfide 5 in 86% yield; 5 is a precursor to some pharmaceutical cores (Scheme 4) [45][46][47][48]. However, α-bromo-δ-valerolactone (3a) was extremely unstable under ambient

• 2a. Synthesis of α-functionalized lactones using the two-phase system. Synthesis of unsymmetrically functionalized sulfide 5 via the two-phase system-promoted intramolecular cyclization of 2b. Sequential nucleophilic substitution in the two-phase system. One-pot synthesis of 2-phenylthio-α

Synthetic strategies toward 1,3-oxathiolane nucleoside analogues

• Umesh P. Aher,
• Dhananjai Srivastava,
• Girij P. Singh and
• Jayashree B. S

Beilstein J. Org. Chem. 2021, 17, 2680–2715, doi:10.3762/bjoc.17.182

• derivative 17. This was obtained as a mixture of endo- and exo-sulfoxides. Esterification of 17 was carried out with dimethyl sulfate to give methyl ester 18, which was further reduced using dichloroborane and dimethyl sulfide to provide sulfide 19 in 80% yield in THF as solvent. Hydrolysis of compound 19

• condensation of the sodium salt of methyl 2-mercaptoacetate (3j) with bromoacetaldehyde diethyl acetal (36) in DMF solvent and further oxidation of the sulfide using m-CPBA, followed by Pummerer rearrangement using Ac2O and sodium acetate at 90 °C, which provides compound 37 (Scheme 9). α-Acetoxy sulfide

• intermediate 37 was resolved using a lipase in t-BuOMe, resulting in a high enantiomeric excess. They used an enzymatic resolution of an acetoxy sulfide with a Pseudomonas fluorescens lipase to obtain compound 38. Reaction of chiral acetoxy sulfide 38 with HCl in dry ethanol induced acetate removal by

Silica gel and microwave-promoted synthesis of dihydropyrrolizines and tetrahydroindolizines from enaminones

• Robin Klintworth,
• Garreth L. Morgans,
• Stefania M. Scalzullo,
• Charles B. de Koning,
• Willem A. L. van Otterlo and
• Joseph P. Michael

Beilstein J. Org. Chem. 2021, 17, 2543–2552, doi:10.3762/bjoc.17.170

• , Stellenbosch University, Matieland 7602, Stellenbosch, South Africa 10.3762/bjoc.17.170 Abstract A wide range of N-(ethoxycarbonylmethyl)enaminones, prepared by the Eschenmoser sulfide contraction between N-(ethoxycarbonylmethyl)pyrrolidine-2-thione and various bromomethyl aryl and heteroaryl ketones

• described in this article. Results and Discussion The benzoyl-containing enaminone 15a (Ar = Ph) was selected as a model for investigating conditions for the cyclization. This compound was conveniently prepared by Eschenmoser sulfide contraction [29][30], as shown in Scheme 2. The route entailed initial

• bromide in acetonitrile at ambient temperature to produce the putative S-alkylated salt was complete within 18 hours, after which treatment with triethyl phosphite and triethylamine rapidly completed the sulfide contraction, giving (E)-enaminone 15a in 92% yield after chromatographic purification. The

Catalyzed and uncatalyzed procedures for the syntheses of isomeric covalent multi-indolyl hetero non-metallides: an account

• Ranadeep Talukdar

Beilstein J. Org. Chem. 2021, 17, 2102–2122, doi:10.3762/bjoc.17.137

• catalytic and uncatalytic synthetic strategies adopted for the synthesis of the non-ionic (non-metallic) versions of these important molecules till date. Keywords: bisindole; heteroatom; indole; selenide; sulfide; Introduction Indole can be considered as a “prodigy” in the family of nitrogen-based

• Friedel–Crafts fashion (Scheme 10a) gave 82 with moderate to good product yields, respectively [69][70]. A similar work by Janosik involved strongly basic conditions at low temperature with bis(phenylsulfonyl)sulfide (83) as the sulfur donor (Scheme 10b) [73][74]. Disulfides are also important reagents

• for accessing bis(indolyl)sulfides. To synthesize the unsymmetrical bis(indolyl)sulfide 88, Janosik reacted the indole disulfide 87 with free indole and obtained the product 88 in 81% yield, where the sulfur linkages were 2,3’- with respect to the two indole nuclei (Scheme 11a) [73][74][75][76]. Hall

Total synthesis of ent-pavettamine

• Memory Zimuwandeyi,
• Manuel A. Fernandes,
• Amanda L. Rousseau and
• Moira L. Bode

Beilstein J. Org. Chem. 2021, 17, 1440–1446, doi:10.3762/bjoc.17.99

• yield. The first step involved esterification of malic acid using methanol, followed by selective reduction of the resulting dimethyl ester using borane dimethyl sulfide (BMS) yielding diol 5 (Scheme 2) [1][14][15]. The step achieved chemo-differentiation of the carboxyl groups present in 3 whilst

Fritsch–Buttenberg–Wiechell rearrangement of magnesium alkylidene carbenoids leading to the formation of alkynes

• Tsutomu Kimura,
• Koto Sekiguchi,
• Akane Ando and
• Aki Imafuji

Beilstein J. Org. Chem. 2021, 17, 1352–1359, doi:10.3762/bjoc.17.94

• olefination of 4,4'-dimethoxybenzophenone with methoxy(trimethylsilyl)methyl p-tolyl sulfide, and oxidation of the resulting 1-methoxyvinyl p-tolyl sulfide with mCPBA (Scheme 3b) [17]. The 1-chlorovinyl p-tolyl sulfoxides 2e–g were prepared through a one-pot procedure (Scheme 3c) [15]. The HWE reagent was

A comprehensive review of flow chemistry techniques tailored to the flavours and fragrances industries

• Guido Gambacorta,
• James S. Sharley and
• Ian R. Baxendale

Beilstein J. Org. Chem. 2021, 17, 1181–1312, doi:10.3762/bjoc.17.90