Generation of alkyl and acyl radicals by visible-light photoredox catalysis: direct activation of C–O bonds in organic transformations

• Mithu Roy,
• Bitan Sardar,
• Itu Mallick and
• Dipankar Srimani

Beilstein J. Org. Chem. 2024, 20, 1348–1375, doi:10.3762/bjoc.20.119

• (Scheme 16). This one-pot strategy involved the reaction of xanthates formed in situ with electron-deficient alkenes under visible-light photoredox conditions in the presence of PPh3. This approach did not require multistep synthesis of starting materials. In addition, alcohol groups in polyols could be

• converted rather selectively in the order tertiary alcohol< secondary alcohol < primary alcohol. They also proposed a mechanism, which is outlined in Scheme 16. The first step involves deprotonation of alcohol in the presence of base and nucleophilic attack of CS2 to generate a xanthate salt intermediate

• , functionalization of alcohols is required, which requires an additional step. Therefore, it is quite interesting to directly employ alcohols for creating carbon-centered radicals that facilitate photomediated organic transformations. In this section, we will discuss some methods where alcohol C–O bonds were

Computation-guided scaffold exploration of 2E,6E-1,10-trans/cis-eunicellanes

• Zining Li,
• Sana Jindani,
• Volga Kojasoy,
• Teresa Ortega,
• Erin M. Marshall,
• Khalil A. Abboud,
• Sandra Loesgen,
• Dean J. Tantillo and
• Jeffrey D. Rudolf

Beilstein J. Org. Chem. 2024, 20, 1320–1326, doi:10.3762/bjoc.20.115

• implies that protonation and cyclization may be concerted for that conformer (Figure S4, Supporting Information File 1). We previously transformed 2 into the trans,trans-6/6/6-tricyclic C6 alcohol 8 using mCPBA to epoxidize the C6–C7 alkene [7]. Under the same conditions, epoxidation of 1 yielded the 6,7

Domino reactions of chromones with activated carbonyl compounds

• Peter Langer

Beilstein J. Org. Chem. 2024, 20, 1256–1269, doi:10.3762/bjoc.20.108

• alcohol and oxidation of the latter resulted in formation of the final product. The reason for the change of the regioselectivity of cyclization, as compared to the formation of products 36, remains unclear at present. The reaction of 3-halochromones with 3H-indole-2-thiones (thiooxindoles) 38a–c afforded

Stability trends in carbocation intermediates stemming from germacrene A and hedycaryol

• Naziha Tarannam,
• Prashant Kumar Gupta,
• Shani Zev and
• Dan Thomas Major

Beilstein J. Org. Chem. 2024, 20, 1189–1197, doi:10.3762/bjoc.20.101

• in a terpene hydrocarbon, or through nucleophilic water attack, yielding a terpene alcohol [5]. To date, about 80,000 terpenes and terpenoids have been discovered [3], approx. 10% of which are sesquiterpenes, composed of 15-carbon skeletons [6][7]. Sesquiterpenes are mainly distributed in plants and

• (Scheme 1) [16]. As an alternative to deprotonation, the germacradienyl cation can be captured by water to yield the sesquiterpene alcohol hedycaryol, which is an important intermediate towards the synthesis of sesquiterpene alcohols [17]. The reprotonation of (R)-(+)-1 germacrene A or hedycaryol at the

Bismuth(III) triflate: an economical and environmentally friendly catalyst for the Nazarov reaction

• Manoel T. Rodrigues Jr.,
• Aline S. B. de Oliveira,
• Ralph C. Gomes,
• Amanda Soares Hirata,
• Lucas A. Zeoly,
• Hugo Santos,
• João Arantes,
• Catarina Sofia Mateus Reis-Silva,
• João Agostinho Machado-Neto,
• Leticia Veras Costa-Lotufo and
• Fernando Coelho

Beilstein J. Org. Chem. 2024, 20, 1167–1178, doi:10.3762/bjoc.20.99

• synthesis has been reported for several transformations, such as epoxide opening [56], ketal formation and deprotection [57][58], Mannich reaction [59], intramolecular Sakurai cyclization [60], alcohol oxidation [61], aromatic hydrocarbon nitration [62], imine allylation [63], Knoevenagel condensation [64

• according to well-established protocols [71][72][73][74]. The β-ketoesters were obtained employing a sequence of two reactions, the formation of the benzylic alcohol derivative, through a Reformatsky reaction using In(0), followed by a pyridinium chlorochromate (PCC) oxidation, giving the β-ketoesters 7a–g

Manganese-catalyzed C–C and C–N bond formation with alcohols via borrowing hydrogen or hydrogen auto-transfer

• Mohd Farhan Ansari,
• Atul Kumar Maurya,
• Abhishek Kumar and
• Saravanakumar Elangovan

Beilstein J. Org. Chem. 2024, 20, 1111–1166, doi:10.3762/bjoc.20.98

• friendly and atom-economical process for C–C and C–N bond formations utilizing alcohol as an alkylating agent and hydrogen donor, producing water as the only side-product [6][7][8][9]. Notably, alcohols are inexpensive, abundant and can be obtained from biomass, which makes this method even more attractive

• to the scientific community [10][11][12]. In this process, first, the metal-catalyzed dehydrogenation of the alcohol provides a reactive substrate for coupling with nucleophiles and the active metal hydride species. Later, the borrowed hydrogen is used in the final step to reduce unsaturated

• synthesis of amines and imines using Mn-pincer catalyst [37]. When t-BuOK (1 equiv) was used as a base, alkylated amine products were observed selectively using alcohol as an alkylating agent, whereas when t-BuONa (1.5 equiv) was used as base, alkylated imine products were isolated (Scheme 6). This

Synthesis of 1,4-azaphosphinine nucleosides and evaluation as inhibitors of human cytidine deaminase and APOBEC3A

• Maksim V. Kvach,
• Stefan Harjes,
• Harikrishnan M. Kurup,
• Geoffrey B. Jameson,
• Elena Harjes and
• Vyacheslav V. Filichev

Beilstein J. Org. Chem. 2024, 20, 1088–1098, doi:10.3762/bjoc.20.96

• phosphinic acid 7 was further protected with benzyl alcohol by a procedure adopted from reference [67] using TBTU and Et3N in refluxing dichloroethane. Compound 8 was obtained in 65% yield after silica gel column chromatography. To synthesise a nucleobase for nucleosides Va and Vb, we first obtained

• dichlorophosphane 9 from commercially available PCl3 and ethyl vinyl ether using a previously published procedure [68]. Compound 9 reacted with 1 equiv of benzyl alcohol in absolute Et2O and pyridine at −78 °C, followed by quenching of the reaction mixture with H2O. This procedure provided phosphinate 10 in more

Carbonylative synthesis and functionalization of indoles

• Alex De Salvo,
• Raffaella Mancuso and
• Xiao-Feng Wu

Beilstein J. Org. Chem. 2024, 20, 973–1000, doi:10.3762/bjoc.20.87

• functionalization of indoles to 3-substituted indoles Functionalization through direct C–H alkoxycarbonylation The transition-metal-catalyzed carbonylation of aryl halides, triflates, and tosylates with carbon monoxide and an alcohol was first pioneered by Heck and co-workers in 1974 [64][65]. Since then, this

Innovative synthesis of drug-like molecules using tetrazole as core building blocks

• Jingyao Li,
• Ajay L. Chandgude,
• Qiang Zheng and
• Alexander Dömling

Beilstein J. Org. Chem. 2024, 20, 950–958, doi:10.3762/bjoc.20.85

• of tetrazole building blocks which provides the handle of alcohol functionality and further oxidation serves as an oxo component in subsequent MCRs (Figure 1d). The synthesis of oxo-tetrazoles was targeted because of the prevalence of the aldehyde substrate in MCRs and their use in medicinal

• isocyanide) in the developed methodology provides multiple opportunities for various further chemical manipulations, easy access of 1H-tetrazole moieties, and great orthogonal functional group compatibility. First, the tetrazole building blocks were prepared on a multi‐gram scale to access the free alcohol

(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

• itself accessible in good yields from allyl chloride 1 using a route based on that reported by Schlüter [28]. Bifunctional 1,2-BCP (±)-4 bearing orthogonally protected alcohol functionalities was obtained from 3a through a three-step sequence of strain-release radical ring-opening with iodochloromethane

• , deiodination at the bridgehead position, and nucleophilic substitution at the alkyl chloride. From 1,2-BCP (±)-4, a variety of 1,2-BCPs were prepared through basic chemical transformations (Scheme 1B) [26]. Selective deprotection gave access to free alcohol-containing 1,2-BCPs (±)-5 and (±)-8. Oxidation and

• esterification of alcohol (±)-5 gave redox active ester (±)-6, which was itself shown to be a suitable substrate for nickel-catalysed decarboxylative cross coupling reactions to aryl-substituted BCPs (±)-7. Oxidation of alcohol (±)-8 gave acid (±)-9 which yielded amine (±)-10 after a Curtius rearrangement

Skeletal rearrangement of 6,8-dioxabicyclo[3.2.1]octan-4-ols promoted by thionyl chloride or Appel conditions

• Martyn Jevric,
• Julian Klepp,
• Johannes Puschnig,
• Oscar Lamb,
• Christopher J. Sumby and
• Ben W. Greatrex

Beilstein J. Org. Chem. 2024, 20, 823–829, doi:10.3762/bjoc.20.74

• the acetal in 3 and 6 to the neighbouring C4-position (Figure 1) [19][20]. A variety of products were reported resulting from fluorination as well as the skeletal rearrangement, with the reaction outcome highly substrate-dependent. A key finding in this work was that the configuration of the alcohol

• biological ribosides. This prompted an investigation of the scope of the SOCl2-mediated rearrangement, with the aim of producing useful chiral materials for synthesis. Results and Discussion The set of bicyclic systems 10a–f with a C4 alcohol were prepared starting with cyrene (2) by alkylation and then

• the exo-face. This process was used to prepare the known compounds 10a–c, and the novel materials 10d–f [9]. Thus, the reaction of o-dibromoxylene with cyrene gave the alcohol 10d in 71% yield over two-steps through the spirocyclic ketone 9d. Alkylation of 2 with methyl iodide gave an inseparable

Discovery and biosynthesis of bacterial drimane-type sesquiterpenoids from Streptomyces clavuligerus

• Dongxu Zhang,
• Wenyu Du,
• Xingming Pan,
• Xiaoxu Lin,
• Fang-Ru Li,
• Qingling Wang,
• Qian Yang,
• Hui-Min Xu and
• Liao-Bin Dong

Beilstein J. Org. Chem. 2024, 20, 815–822, doi:10.3762/bjoc.20.73

• DL10092 displayed a new peak in its HPLC profile compared to the control of wild-type E. coli BL21 (DE3) (see Figure S9 in Supporting Information File 1). The fermented product appeared as an alcohol, likely due to the activity of the endogenous hydrolase in E. coli. The retention time of the new peak was

Advancements in hydrochlorination of alkenes

• Daniel S. Müller

Beilstein J. Org. Chem. 2024, 20, 787–814, doi:10.3762/bjoc.20.72

• solution of HCl, even in the presence of secondary alcohol and ester functionalities (Scheme 5B) [45]. An application in the synthesis of Δ9-tetrahydrocannabutol, the butyl homologue of Δ9-tetrahydrocannabinol (Δ9-THC), is outlined in Scheme 5C [46]. In this case, ZnCl2 was employed as a catalyst, but

• potential safety hazards, especially in large-scale reactions [53]. Instead of acetyl chlorides, various other reagents, including pivaloyl chloride, oxalyl chloride, SOCl2, and TMSCl, can be employed to generate HCl. Numerous proton donors, such as water, alcohol, phenol, or acidic C–H groups, have been

•  18A). The reaction worked exclusively for reactive alkenes such as 1,1-disubstituted or trisubstituted alkenes. No conversion was observed for terminal alkenes and 1,2-substituted alkenes. When exposing citronellol (122) to the reaction conditions, the alcohol was rapidly converted to the acetate and

Substrate specificity of a ketosynthase domain involved in bacillaene biosynthesis

• Zhiyong Yin and
• Jeroen S. Dickschat

Beilstein J. Org. Chem. 2024, 20, 734–740, doi:10.3762/bjoc.20.67

• are suggested not to catalyse elongations, but the KS domains of modules 5 and 9 may only act in the translocation of the intermediate from the ACP of the previous module to the ACP of modules 5 and 9, respectively. Modules 5 and 9 then only catalyse the dehydration of the alcohol functions installed

• benzyl alcohol to obtain the unlabelled ester 5 with a quantitative yield over two steps. After having established this method, (5-13C)glutamic acid (3) was converted analogously into (1-13C)-5, unfortunately with a little lower, but still very good yield of 83%. By employing Yamaguchi conditions, the

Chemoenzymatic synthesis of macrocyclic peptides and polyketides via thioesterase-catalyzed macrocyclization

• Senze Qiao,
• Zhongyu Cheng and
• Fuzhuo Li

Beilstein J. Org. Chem. 2024, 20, 721–733, doi:10.3762/bjoc.20.66

• TE-catalyzed marcolactonization [69]. The synthesis of linear peptide 34 commenced with the lactone opening of 26 to afford Weinreb amide 27. Following primary alcohol protection and amide reduction, the aldehyde 28 was coupled with iodide 29 to afford 30 via Nozaki–Hiyama–Kishi coupling, which was

• then transformed into aldehyde 31 through several protecting group adjustments and the corresponding alcohol and Ley oxidation. After the preparation of 33 using Evans syn-aldol condensation as a critical step, 34 was produced by thioester formation, desilylation, and allylic oxidation. Incubating 34

• epoxidation with enzymatic macrocyclization in 2020 as shown in Scheme 8 [85]. According to their previous report [86], the production of fragments 61 was initiated by Evans’ asymmetric aldol and alcohol protection to generate 57. Six-step route transformations, including cross metathesis, afforded aldehyde

SOMOphilic alkyne vs radical-polar crossover approaches: The full story of the azido-alkynylation of alkenes

• Julien Borrel and
• Jerome Waser

Beilstein J. Org. Chem. 2024, 20, 701–713, doi:10.3762/bjoc.20.64

• presence of transition metal catalysts [11][12][13][14]. Currently, this motif is synthesized by sequential introduction of the two functional groups [11][12][13]. Addition of a lithium acetylide to an epoxide affords the corresponding homopropargylic alcohol which can then undergo a sequence of mesylation

New variochelins from soil-isolated Variovorax sp. H002

• Jabal Rahmat Haedar,
• Aya Yoshimura and
• Toshiyuki Wakimoto

Beilstein J. Org. Chem. 2024, 20, 692–700, doi:10.3762/bjoc.20.63

• for 1 h with 10 mg/mL lysozyme. After 10% SDS was added to the tube, the mixture was incubated at room temperature, 60 °C, and then 0 °C, for 5 min durations. AcOK (5 M) and phenol/CHCl3/isoamyl alcohol (25:24:1) were then added, and the resulting solution was gently mixed by inversion and centrifuged

Palladium-catalyzed three-component radical-polar crossover carboamination of 1,3-dienes or allenes with diazo esters and amines

• Geng-Xin Liu,
• Xiao-Ting Jie,
• Ge-Jun Niu,
• Li-Sheng Yang,
• Xing-Lin Li,
• Jian Luo and
• Wen-Hao Hu

Beilstein J. Org. Chem. 2024, 20, 661–671, doi:10.3762/bjoc.20.59

• , amoxapine, an ibrutinib derivative, N-desmethyl sildenafil, silodosin, and lapatinib (4d–k, 35–67%). The late-stage modification of these drug agents and their derivatives in this MCR underlined the synthetic value and high functional group tolerance (e.g., aromatic amine, amide, alcohol, heterocycle). We

Chemical and biosynthetic potential of Penicillium shentong XL-F41

• Ran Zou,
• Xin Li,
• Xiaochen Chen,
• Yue-Wei Guo and
• Baofu Xu

Beilstein J. Org. Chem. 2024, 20, 597–606, doi:10.3762/bjoc.20.52

• , such as medium-chain alcohol dehydrogenase (CpDCS), esterase (CpDCE), P450 and O-methyltransferase (CpOMT1) (Figure S37). Through genome excavation and analysis of Penicillium shentong XL-F41, a significant difference was discovered between the key enzymes involved in the formation of product compound

Entry to new spiroheterocycles via tandem Rh(II)-catalyzed O–H insertion/base-promoted cyclization involving diazoarylidene succinimides

• Alexander Yanovich,
• Anastasia Vepreva,
• Ksenia Malkova,
• Grigory Kantin and
• Dmitry Dar’in

Beilstein J. Org. Chem. 2024, 20, 561–569, doi:10.3762/bjoc.20.48

• of compound 4b has been confirmed by single crystal X-ray data. The next step was to investigate the possibility of obtaining six-membered oxygen-containing spiroheterocycles by interaction of DAS 1 with 2-(bromomethyl)benzyl alcohol (15) (Scheme 6). The synthesis was carried out under the conditions

• summarized in Scheme 8). The first pathway is realized in the formation of five-membered (in the case of 3-bromopropanol) and six-membered (in the case of 2-(bromomethyl)benzyl alcohol) cycles – the cyclization of the anion is faster than its reverse protonation. The same applies to substrates with activated

• alcohol followed by base-promoted cyclization. The procedures developed allow to obtain derivatives of such sought-after scaffolds in the field of medicinal chemistry as Δα,β-butenolides, tetrahydrofurans, and pyrans spiro-conjugated with a pyrrolidine ring. The tandem approach proposed is characterized

Switchable molecular tweezers: design and applications

• Pablo Msellem,
• Maksym Dekthiarenko,
• Nihal Hadj Seyd and
• Guillaume Vives

Beilstein J. Org. Chem. 2024, 20, 504–539, doi:10.3762/bjoc.20.45

Ligand effects, solvent cooperation, and large kinetic solvent deuterium isotope effects in gold(I)-catalyzed intramolecular alkene hydroamination

• Ruichen Lan,
• Brock Yager,
• Yoonsun Jee,
• Cynthia S. Day and
• Amanda C. Jones

Beilstein J. Org. Chem. 2024, 20, 479–496, doi:10.3762/bjoc.20.43

• -withdrawing phosphines. A DCM/alcohol cooperative effect was quantified, and a continuum of isotope effects was measured with low KIE’s in the absence of deuterated alcoholic solvent, increasing to large solvent KIE’s when comparing reactions in pure MeOH to those in pure MeOH-d4. The effects are interpreted

• Lewis bases as additive to the bulk CH2Cl2 solvent (Figure 6) and compared them to the baseline rate in the absence of additive. The rates of formation of 3a are mildly sensitive to alcohol structure with MeOH outperforming EtOH and propanol. For the set of linear alcohols, the shorter the chain, the

• behaves accordingly here [66]. Specific gold–oxygen interactions are typically not invoked in mechanistic discussions, though a gold alcohol complex has been proposed in silyl enol ether protonation [67]. Equilibrium studies by Maier et al. indicate that methanol is more weakly coordinating than alkynes

(E,Z)-1,1,1,4,4,4-Hexafluorobut-2-enes: hydrofluoroolefins halogenation/dehydrohalogenation cascade to reach new fluorinated allene

• Nataliia V. Kirij,
• Andrey A. Filatov,
• Yurii L. Yagupolskii,
• Sheng Peng and
• Lee Sprague

Beilstein J. Org. Chem. 2024, 20, 452–459, doi:10.3762/bjoc.20.40

• 11 had an allene structure. It was also important to note that the reaction proceeded more selectively in ether, which significantly reduced the amount of byproducts. Pure final alcohol 10 was isolated by column chromatography on SiO2 in 46% yield and 1H, 19F and 13C NMR spectra were in full

Mechanisms for radical reactions initiating from N-hydroxyphthalimide esters

• Carlos R. Azpilcueta-Nicolas and
• Jean-Philip Lumb

Beilstein J. Org. Chem. 2024, 20, 346–378, doi:10.3762/bjoc.20.35

• substitution with alcohol 94 in the presence of lithium phthalimide 95 leads to product 96 and turns over the catalytic cycle. Importantly, species 93 can be detected by high resolution mass spectrometry, when the reaction is carried out without nucleophile and using stoichiometric amounts of PTH1. H. Fu and

Nucleophilic functionalization of thianthrenium salts under basic conditions

• Xinting Fan,
• Duo Zhang,
• Xiangchuan Xiu,
• Bin Xu,
• Yu Yuan,
• Feng Chen and
• Pan Gao

Beilstein J. Org. Chem. 2024, 20, 257–263, doi:10.3762/bjoc.20.26

• Abstract In recent years, S-(alkyl)thianthrenium salts have become an important means of functionalizing alcohol compounds. However, additional transition metal catalysts and/or visible light are required. Herein, a direct thioetherification/amination reaction of thianthrenium salts is realized under metal

• -free conditions. This strategy exhibits good functional-group tolerance, operational simplicity, and an extensive range of compatible substrates. Keywords: amination; functionalization of alcohol; metal-free; S-(alkyl)thianthrenium salts; thioetherification; Introduction Sulfonium salts [1][2][3][4