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

• facilitate important chemical reactions. Thus, we will focus on the reports detailing organic transformations that proceed via visible-light-induced deoxygenative generation of acyl radicals from carboxylic acids and acid anhydrides that have appeared since 2019. Review General mechanism of photoredox

• catalysis In recent times, visible-light-mediated photoredox chemistry has evolved as a unique tool for various organic transformations. In contrast to traditional catalysis, the photochemical process uses an electron or energy transfer mechanism to form reactive intermediates. Typically, a photocatalyst is

• conventional metal hydrides, such as tin or silicon hydrides. The reaction mechanism is interesting since first, a Lewis acid–base adduct is generated by interaction of Et3N with a boron atom of bis(catecholato)diboron (B2cat2, 19). As a result, one of the catecholate ligands experiences an increase in

Rhodium-catalyzed homo-coupling reaction of aryl Grignard reagents and its application for the synthesis of an integrin inhibitor

• Kazuyuki Sato,
• Satoki Teranishi,
• Atsushi Sakaue,
• Yukiko Karuo,
• Atsushi Tarui,
• Kentaro Kawai,
• Hiroyuki Takeda,
• Tatsuo Kinashi and
• Masaaki Omote

Beilstein J. Org. Chem. 2024, 20, 1341–1347, doi:10.3762/bjoc.20.118

• previous results [21][22]. Consequently, we propose the reaction mechanism as shown in Figure 2. In the initial step, the Rh catalyst reacts with the Grignard reagent 4 to give the Rh(I)–aryl complex 7. Oxidative addition of 1,2-dibromoethane onto complex 7 then generates Rh(III)–aryl complex 8 along with

• . Conditions: a) The reaction was carried out at rt for 1–3 h without Mg. b) The side product 6h by SNAr reaction onto 3h was obtained in 8%. Tentative reaction mechanism. Ullmann and Ullmann-type homo-coupling reactions. Rh-catalyzed homo-coupling reactions. Rh-catalyzed homo-coupling reaction by using

Synthesis of 1,2,3-triazoles containing an allomaltol moiety from substituted pyrano[2,3-d]isoxazolones via base-promoted Boulton–Katritzky rearrangement

• Constantine V. Milyutin,
• Andrey N. Komogortsev and
• Boris V. Lichitsky

Beilstein J. Org. Chem. 2024, 20, 1334–1340, doi:10.3762/bjoc.20.117

• spectroscopy and high-resolution mass spectrometry. Moreover, X-ray analysis was used for confirmation of structure of compound 4g (Figure 1). A plausible mechanism of the studied rearrangement is presented in Scheme 5. At first, anion A is generated from starting hydrazone 3 under action of base. Next

• obtained the recyclized product 6a (Scheme 6), whose structure was confirmed by 1H, 13C NMR spectroscopy, high-resolution mass spectrometry and X-ray analysis. Based on the aforementioned reaction we have synthesized a set of pyrazolylisoxazoles 6 (Scheme 7). The proposed mechanism of investigated

• hydrazone 3a. Synthesis of hydrazone 3b using phenylhydrazine hydrochloride. Synthesis of target 1,2,3-triazoles 4. Reaction conditions: 1 (0.5 mmol), arylhydrazine hydrochloride (0.55 mmol), EtOH (5 ml), then K2CO3 (1.5 mmol, 0.21 g), EtOH (5 ml). Proposed reaction mechanism. Reaction of 1d with hydrazine

Transition-metal-catalyst-free electroreductive alkene hydroarylation with aryl halides under visible-light irradiation

• Kosuke Yamamoto,
• Kazuhisa Arita,
• Masami Kuriyama and
• Osamu Onomura

Beilstein J. Org. Chem. 2024, 20, 1327–1333, doi:10.3762/bjoc.20.116

• , providing the corresponding product 3aa in 74% yield. Several control experiments were conducted to gain insight into the reaction mechanism of the electroreductive process. The hydroarylation of cyclopropane-substituted styrene 2l resulted in the formation of ring-opening product 3al’, and the simple

• electroreductive reaction would proceed through a reductive radical-polar crossover pathway [57]. On the basis of mechanistic investigations and a literature report [47], a plausible mechanism for this electroreductive hydroarylation is depicted in Scheme 4. 1,3-DCB (Ep/2 = −1.9 V vs SCE in MeCN) [58] undergoes

• ), 1,3-DCB (50 mol %), H2O (5.0 mmol), Et4NCl (0.1 mmol), MeCN (3 mL), Al(+)-Pt(−), 7.5 mA/cm2, 4.5 F/mol, 0 °C, blue LEDs. a4.5 F/mol. b2 (5 equiv). cMeCN (3 mL). d5 F/mol. 1,3-DCB, 1,3-dicyanobenzene. Gram-scale reaction and control experiments. Plausible mechanism. Evaluation of reaction conditions.a

Sustainable tandem acylation/Diels–Alder reaction toward versatile tricyclic epoxyisoindole-7-carboxylic acids in renewable green solvents

• Ayhan Yıldırım

Beilstein J. Org. Chem. 2024, 20, 1308–1319, doi:10.3762/bjoc.20.114

• 2.160 Å. These bond lengths support path I, which is a more valid pathway in the reaction mechanism. As can be seen in Figure 4, the energies of both the exo transition state and the exo product are lower than those of the endo, which also supports the experimental results. Conclusion Vegetable oils

• , 47.03, 45.86; Anal calcd for C16H15NO4 (285.30): C, 67.36; H, 5.30; N, 4.91; found: C, 67.30; H, 5.26; N, 4.86. Reaction yields after seven uses of SSO and average recovery of the oil. Coupling constants of selected protons in compound 2a and its optimized geometric structure. Possible mechanism for the

Domino reactions of chromones with activated carbonyl compounds

• Peter Langer

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

• triethylamine in methanol afforded benzocoumarines 18a–ac (Scheme 4) [33][34]. The formation of the product, which was obtained in a two-step one-pot reaction, can be explained by a mechanism similar to the one discussed for the formation of 17. 1,4-Addition gave intermediate D which was isolated, but used in

• -butadienes The reaction of 3-formyl- and 3-acetylchromones 10a–i with 1,3-bis(silyloxy)-1,3-butadienes 6a–h, catalysed by Me3SiOTf, afforded hydroxylated benzophenones 20a–ag (Scheme 6) [35][36]. The products are formed by a mechanism related to the one discussed for the formation of products 19a–d. The same

• with 1,3-bis(silyloxy)-1,3-butadienes 6a–z afforded azaxanthones 41a–am (Scheme 23) [45][46]. The formation of the products can be explained by the mechanism discussed for the formation of azaxanthone 40 that involves intermediates AF and AG. For most products, the yields were in the range of 30 to 66

Mechanistic investigations of polyaza[7]helicene in photoredox and energy transfer catalysis

• Johannes Rocker,
• Till J. B. Zähringer,
• Matthias Schmitz,
• Till Opatz and
• Christoph Kerzig

Beilstein J. Org. Chem. 2024, 20, 1236–1245, doi:10.3762/bjoc.20.106

• cation was directly observed confirming the previously proposed mechanism of a three-component reaction. Several steps of the photoredox cycle were investigated separately, providing deep insights into the complex mechanism. The triplet-excited Aza-H, which was studied with quantitative LFP, is formed

• mechanism of the recently reported sulfonylation/arylation [45][46] reaction using laser flash photolysis (LFP). LFP is a powerful spectroscopic tool in photocatalysis that allows us not only to distinguish between energy and electron transfer but also to detect transient triplet states and radicals

• , yielding clear-cut evidence for the proposed reaction mechanism [47][48][49][50][51][52][53][54][55][56][57]. We found that quenching of the singlet-excited Aza-H by 4-cyanopyridine is the main pathway for the 3-CR, while the triplet state of our catalyst, which is formed with a quantum yield as high as

Competing electrophilic substitution and oxidative polymerization of arylamines with selenium dioxide

• Vishnu Selladurai and
• Selvakumar Karuthapandi

Beilstein J. Org. Chem. 2024, 20, 1221–1235, doi:10.3762/bjoc.20.105

• been used in oxyselenenylation of olefins, which follows an electrophilic addition mechanism [23][24][25]. However, such reagents are rarely used for electrophilic substitution of aromatic systems. Recently, notable progress has been made in the use of aromatic electrophilic substitution to synthesize

• after 24 h. Whereas at the same molar ratio, polymers 1 and 2 were obtained in larger quantities of ≈2.3 g after the short time of 3 h (see Experimental section for details). Mechanistic aspects Mechanism for the formation of diaryl monoselenides The plausible mechanism for the formation of diaryl

• rise to either diaryl selenoxide via dehydration or diaryl monoselenide via reductive elimination by eliminating H2O2 [39]. Observation of m/z peaks for compound 8 clearly confirmed the formation of diaryl selenoxide in the reaction. Mechanism for the formation of oxamides The possible reaction

Cofactor-independent C–C bond cleavage reactions catalyzed by the AlpJ family of oxygenases in atypical angucycline biosynthesis

• Jinmin Gao,
• Liyuan Li,
• Shijie Shen,
• Guomin Ai,
• Bin Wang,
• Fang Guo,
• Tongjian Yang,
• Hui Han,
• Zhengren Xu,
• Guohui Pan and
• Keqiang Fan

Beilstein J. Org. Chem. 2024, 20, 1198–1206, doi:10.3762/bjoc.20.102

• -dependent reactions of AlpJ-family oxygenases. Furthermore, the AlpJ- and JadG-catalyzed reactions of CR1 could be quenched by superoxide dismutase, supporting a catalytic mechanism wherein the substrate CR1 reductively activates molecular oxygen, generating a substrate radical and the superoxide anion O2

• •−. Our findings illuminate a substrate-controlled catalytic mechanism of AlpJ-family oxygenases, expanding the realm of cofactor-independent oxygenases. Notably, AlpJ-family oxygenases stand as a pioneering example of enzymes capable of catalyzing oxidative reactions in either an FADH2/FMNH2-dependent or

• bond cleavage, ring opening, and rearrangement reactions, yielding the respective products. Furthermore, the reactions of 8 catalyzed by JadG and AlpJ could be quenched by superoxide dismutase (SOD), supporting a catalytic mechanism involving the generation of a substrate radical and the superoxide

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

• formation of (6,6) vs (5,7) is rooted in very slight changes in mechanism (protonation at C1 vs C10), it is of interest to understand whether there is a systematic difference in energy. In cases where enzymes use pathways with high-energy intermediates, the enzyme active site must in some way direct the

Two-fold addition reaction of silylene to C₆₀: structural and electronic properties of a bis-adduct

• Masahiro Kako,
• Masato Kai,
• Masanori Yasui,
• Michio Yamada,
• Yutaka Maeda and
• Takeshi Akasaka

Beilstein J. Org. Chem. 2024, 20, 1179–1188, doi:10.3762/bjoc.20.100

• . The regioselectivity in the addition reaction of 1 with C70 was explained earlier in terms of the interaction between the HOMO of 1 and the LUMO of C70 [16]. The reaction mechanism of ethylene with a silylene substituted with thiolate ligands has been studied using theoretical calculations, in which

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

• , respectively. The proposed mechanism suggested that the active amido species (Mn5-a) was formed by treating Mn5 with the base. Then, the alkoxy intermediate Mn5-b is formed by reaction with the alcohol followed by release of an aldehyde and formation of the manganese hydride Mn5-c. The released aldehyde

• mesitylene (Scheme 13). The formation of manganese(III) alkoxide intermediate Mn7-a, was believed to be the first step in the reaction mechanism which then releases the aldehyde under formation of hydride complex, Mn7-b. Then, the alcohol reacts with the hydride complex under release of hydrogen gas and

• , giving 88% yield of the desired alkylated product. Several ketones were studied under the same conditions, with substituted benzyl and aliphatic alcohols giving up to 92% yield of the corresponding C-alkylated products (Scheme 24). The proposed mechanism showed that the pre-catalyst Mn1 was first

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

• of the University of Auckland, Level 2, 3A Symonds Street, Auckland 1142, New Zealand 10.3762/bjoc.20.96 Abstract Nucleoside and polynucleotide cytidine deaminases (CDAs), such as CDA and APOBEC3, share a similar mechanism of cytosine to uracil conversion. In 1984, phosphapyrimidine riboside was

• accelerated by enzymes. These enzymes share a similar mechanism of cytosine deamination and a similar tertiary structure. Despite this similarity, individual enzymes are selective for the corresponding cytosine-containing substrates with little or no cross-reactivity. Cytosine deaminase, which is present in

• . We demonstrated that dZ (IIc) does not inhibit A3 enzymes as the free nucleoside but becomes a low-µM inhibitor if it is used in ssDNA instead of the target dC in the recognition motifs of A3A/A3B and A3G [54]. This observation supports a mechanism in which ssDNA delivers dZ (IIc) to the active site

Light on the sustainable preparation of aryl-cored dibromides

• Fabrizio Roncaglia,
• Alberto Ughetti,
• Nicola Porcelli,
• Biagio Anderlini,
• Andrea Severini and
• Luca Rigamonti

Beilstein J. Org. Chem. 2024, 20, 1076–1087, doi:10.3762/bjoc.20.95

• functionalisation on the aromatic ring when used in the dark [20]. A classic example is the bromination of toluene with molecular bromine. When the system is exposed to light (right side of Figure 1), a radical mechanism is initiated by Br• coming from Br2 homolysis. Propagation involves the reversible abstraction

• follows a different mechanism, producing the ortho and para-bromoarenes through Ar-SE, that involves cationic intermediates. In this case, a catalytic amount of iodine [21][22] or FeCl3 [23] is added to enhance the electrophilicity of bromine. While widely employed and capable of producing reliable

• Ar-SE mechanism, which is reported to proceed through the generation of a mixed molecular halogen [28]. As an alternative to iodine, the trityl cation [29] is reported too. Additional benefits of the method include its ability to work in neutral conditions, and the potential quantitative

Novel route to enhance the thermo-optical performance of bicyclic diene photoswitches for solar thermal batteries

• Akanksha Ashok Sangolkar,
• Rama Krishna Kadiyam and
• Ravinder Pawar

Beilstein J. Org. Chem. 2024, 20, 1053–1068, doi:10.3762/bjoc.20.93

• . A schematic representation of the photoswitching mechanism operating in the studied BBD-based switches for MOST application is illustrated in Figure 1d. The parent BBD molecules absorb incoming photons from solar radiation and undergo photoinduced electronic excitation. The excited diene thereafter

• generated. The thermal stability and reversibility of the photoswitching cycle of the type-IIa photoswitch was analyzed using the ab initio molecular dynamics (AIMD) simulations. The proposed mechanism for the thermal back conversion and undesired thermal degradation of the photoproduct is illustrated in

• Figure 7. As mentioned earlier, the dissociation of the two newly formed σ-bonds proceeds in a highly asynchronous mechanism. Therefore, initially, only one of the two σ-bonds denoted as α bond in the photoproducts (Figure 7) dissociates to form a TS structure having singlet biradicaloid. Subsequently

Structure–property relationships in dicyanopyrazinoquinoxalines and their hydrogen-bonding-capable dihydropyrazinoquinoxalinedione derivatives

• Tural N. Akhmedov,
• Ajeet Kumar,
• Daken J. Starkenburg,
• Kyle J. Chesney,
• Khalil A. Abboud,
• Novruz G. Akhmedov,
• Jiangeng Xue and
• Ronald K. Castellano

Beilstein J. Org. Chem. 2024, 20, 1037–1052, doi:10.3762/bjoc.20.92

• , ethanol, ethylene glycol, and diethylene glycol in the presence of excess triethylamine (Scheme 2). These products provide evidence for the in situ formation of DCPQ 7a and demonstrate its ability to undergo trapping with various nucleophiles through an SNAr mechanism. An alternate strategy was employed

•  1). The H-bonding capable dihydropyrazinoquinoxaline diones (DPQDs) were obtained by a SNAr mechanism involving the corresponding DCPQ derivatives. Based on numerous examples in the literature, it has been established that for electron-deficient π-systems containing cyano groups, the addition

Auxiliary strategy for the general and practical synthesis of diaryliodonium(III) salts with diverse organocarboxylate counterions

• Naoki Miyamoto,
• Daichi Koseki,
• Kohei Sumida,
• Elghareeb E. Elboray,
• Naoko Takenaga,
• Ravi Kumar and
• Toshifumi Dohi

Beilstein J. Org. Chem. 2024, 20, 1020–1028, doi:10.3762/bjoc.20.90

• of the fluorescent-labeling carboxylic acid 6j (see Supporting Information File 1, Figure S1). Thus, this post-fluorescence iodonium salt can be used for visual indication of the ligand exchange process, elucidating the arylation mechanism of diaryliodonium(III) salts for their further applications

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

• reaction mechanism proceeds with an initial reduction of Pd(II) to Pd(0) followed by oxidative addition on the ArCH2–Cl bond to form the ArCH2–PdII–Cl complex. Then, insertion of CO, from TFBen, takes place followed by nucleophilic displacement and reductive elimination. The obtained compound undergoes

• . Meanwhile, they also discovered that by conducting the reaction under non-oxidative conditions the reaction mechanism changed, leading to the formation of indol-2-acetic esters via the H–PdII–I species formed in situ [19]. The reaction was performed in the presence of PdI2 and KI (2 mol % and 20 mol

• the catalyst undergoes reduction, therefore, rather using only CO, a mixture of CO–air (12:48 bar) was used with the aim of oxidizing the Pd(0) species in order to restore the catalyst able to catalyze the process again. The reaction mechanism proceeds with an initial interaction between the Pd(II

Enhancing structural diversity of terpenoids by multisubstrate terpene synthases

• Min Li and
• Hui Tao

Beilstein J. Org. Chem. 2024, 20, 959–972, doi:10.3762/bjoc.20.86

• they often synthesize multiple products from a single substrate through complex cyclization cascades [4][5][6][7][8][9][10]. Based on the mechanism of initial carbocation generation, TSs generally fall into two main classes. Class I TSs generate an allylic cation from a prenyl substrate by

• analogues 80 and 81 with shifted double bonds were synthesized to study the stereochemistry and cyclization mechanism of casbene synthase (CS) from the castor bean (Ricinus communis), which indicated a stereochemical course in accordance with the reported absolute configuration of casbene [41] (Figure 6b

• 82 and 83 by TSs led to the production of ruptenes including compounds 84–90, which revealed the structure of the proposed intermediates for the cyclization reactions and therefore provided important insights into the reaction mechanism [49] (Figure 6c). With the aid of artificial prenyl analogs, a

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 product (Table 1, entry 9). Although representing a considerable drop in efficiency compared to using 1.25 equiv of BT-SCF3, this observation provides an interesting insight into the reaction mechanism (vide infra). Changing the solvent from DCM to THF or MeCN resulted in no significant change in

• , replacing the benzylamine coupling partner with phenylalanine methyl ester provided dipeptide 5t in 67% yield (Scheme 3b). With the scope of the deoxyfluorination process established, our attention turned to an investigation of the reaction mechanism (Scheme 4). As demonstrated in our previous work

• thioester 3a and the remaining 0.5 equiv of 1a and 0.5 equiv of DIPEA were then added (Scheme 5c). According to the mechanism shown in Scheme 4, self-propagating conversion of 3a into 2a, presumably initiated by a carboxylate nucleophile, would account for half of the acyl fluoride formed with the remaining

Confirmation of the stereochemistry of spiroviolene

• Yao Kong,
• Yuanning Liu,
• Kaibiao Wang,
• Tao Wang,
• Chen Wang,
• Ben Ai,
• Hongli Jia,
• Guohui Pan,
• Min Yin and
• Zhengren Xu

Beilstein J. Org. Chem. 2024, 20, 852–858, doi:10.3762/bjoc.20.77

• cyclization mechanism of spiroviolene. Keywords: boron migration; diterpene; spiroviolene; stereochemistry; Introduction Terpenes represent one of the most fascinating families of natural products due to their structural complexity and diversity, as well as their indispensable biological functions that

• proposing a reasonable cyclization mechanism [5]. Spiroviolene (1, Figure 1) was identified by Dickschat and co-workers as a nascent cyclization product of spiroviolene synthase (SvS), the coding gene of which was cloned from Streptomyces violens NRRL ISP-5597 [6]. Its unique spiro-fused linear triquinane

• , direct evidences such as single-crystal X-ray diffraction results were not reported in their study. The reassignment of the stereochemistry at C3 has resulted in the revision of the proposed cyclization mechanism [12][13][14]. The revised mechanism resembled the cyclization process for the formation of

Ortho-ester-substituted diaryliodonium salts enabled regioselective arylocyclization of naphthols toward 3,4-benzocoumarins

• Ke Jiang,
• Cheng Pan,
• Limin Wang,
• Hao-Yang Wang and
• Jianwei Han

Beilstein J. Org. Chem. 2024, 20, 841–851, doi:10.3762/bjoc.20.76

• -positions to the ester group were all well-tolerated (Table 3). To gain further insights into the reaction mechanism, we conducted control experiments. Given the utility of diaryliodonium salts in radical chemistry, we introduced 2 equivalents of 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) or 2 equivalents

• tested in the reaction under the standard conditions, however, product 3aa was not obtained. Based on the literature known results and the experimental evidences [35][36], we proposed a plausible reaction mechanism (Scheme 2b). The reaction started with the formation of radical intermediate A from

• protocol enables the efficient formation of two chemical bonds in one pot, representing a valuable tool for the synthesis of polycyclic benzocoumarins. Our ongoing research endeavours are dedicated to explore the detailed reaction mechanism with the ultimate aim of broadening the scope and applicability of

Activity assays of NnlA homologs suggest the natural product N-nitroglycine is degraded by diverse bacteria

• Kara A. Strickland,
• Brenda Martinez Rodriguez,
• Ashley A. Holland,
• Shelby Wagner,
• Michelle Luna-Alva,
• David E. Graham and
• Jonathan D. Caranto

Beilstein J. Org. Chem. 2024, 20, 830–840, doi:10.3762/bjoc.20.75

• was attributed to a manganese peroxidase, however, the mechanism of degradation is unclear. Linear nitramines, produced by carbon capture, were shown to be biodegraded in soil and water [19]. Nitramines with hydroxy groups were best degraded in this study, including diethylnitramine, 2-methyl-2

• producers and of NNG is unknown. Additionally, NNG’s physiological function is unknown, but it is toxic to plants, mice, and Gram-negative bacteria [25][26]. While there is no direct evidence of the mechanism of this toxicity, NNG has been shown to competitively inhibit succinate dehydrogenase, a component

• may occur non-enzymatically or is catalyzed within the NnlA active site. However, an imine product has not yet been observed and further investigations of the NNG degradation mechanism are needed. Given the potential widespread presence of NnlA, it is possible that NnlA could mediate previously

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

• small amounts of the C2 epimers. Oxidation of the hemiacetal 12a gave a moderate and unoptimised yield of 40% for lactone 24. The probable mechanism for the transformation with SOCl2 and under Appel conditions is shown in Figure 2. The reaction of alcohol 10 with the electrophiles gives the

• levoglucosenone, cyrene and their derivatives, generating a unique set of bicyclic building blocks. Previous work on migration reactions in 6,8-dioxabicyclooctan-4-ols [18]. Mechanism for the rearrangement of 10, and Newman projection and the X-ray structure of 10d projected along the C4–C5 axis. Structures for

Advancements in hydrochlorination of alkenes

• Daniel S. Müller

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

• the alkene in the first step, providing a carbocation that subsequently reacts with a chloride anion to yield the Markovnikov product. While this ionic mechanism is commonly illustrated in textbooks by showing “naked” cations as intermediates, several recent studies suggest a molecular concerted or

• simultaneous mechanism [15][16][17][18][19]. 2) Radical hydrochlorinations: These reactions involve the in situ formation of a carbon-centered radical, which is then trapped by an appropriate chlorine source. 3) anti-Markovnikov products: This category describes a new field in hydrochlorination reactions

• following mechanism (Scheme 30B): Initially, the terminal palladium species H, formed through the hydropalladation of terminal or internal alkenes (upon chain walking), coordinates to NCS via hydrogen bonding (I). Subsequent oxidation takes place to yield a Pd(IV) species (J), which then undergoes reductive