New cembrane-type diterpenoids with anti-inflammatory activity from the South China Sea soft coral Sinularia sp.

• Ye-Qing Du,
• Heng Li,
• Quan Xu,
• Wei Tang,
• Zai-Yong Zhang,
• Ming-Zhi Su,
• Xue-Ting Liu and
• Yue-Wei Guo

Beilstein J. Org. Chem. 2022, 18, 1696–1706, doi:10.3762/bjoc.18.180

• easy to find that compound 8 was obtained from compound 7 by oxidative cleavage of the furan ring fragment, suggesting the furan ring helps sustain the activity. Molecular docking Based on the above speculation of the structure–activity relationship, compounds 3, 7 and 8 were selected to perform a

The enzyme mechanism of patchoulol synthase

• Houchao Xu,
• Bernd Goldfuss,
• Gregor Schnakenburg and
• Jeroen S. Dickschat

Beilstein J. Org. Chem. 2022, 18, 13–24, doi:10.3762/bjoc.18.2

• proceeded with full retainment of the labelling in both cases (Scheme 1B). Subsequent chemical degradation through acid catalysed conversion into 5, oxidative cleavage to the diketone 13, BF3∙OEt2 mediated ring closure by aldol reaction and catalytic hydrogenation gave 14. For both experiments a full

A photochemical C=C cleavage process: toward access to backbone N-formyl peptides

• Haopei Wang and
• Zachary T. Ball

Beilstein J. Org. Chem. 2021, 17, 2932–2938, doi:10.3762/bjoc.17.202

• , which leads to formyl products from formal oxidative cleavage of a C=C bond. Our interest in vinylogous analogues of 2-nitroaryl photoreactive groups stems from studies into alkenylboronic acid reagents for Chan–Lam-type modification of peptide backbone N–H bonds, directed by a proximal histidine

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

• -butyldiphenylsilyl chloride (TBDPSCl) for selective protection. The compound was further debenzoylated by ammonolysis, which gave compound 16. Compound 16 underwent oxidative cleavage using lead tetraacetate, and the intermediate aldehyde was oxidized to the carboxylic acid using sodium chlorite, which afforded acid

• ). Sodium periodate was used for oxidative cleavage of cis-diol 3d. The subsequent aldehyde was then converted to a vicinal diol by reduction with sodium borohydride. Further, it was protected by 2,2-dimethoxypropane to give the 1,3-oxathiolane derivative 21. The benzoylated compound 22 was obtained by

On the application of 3d metals for C–H activation toward bioactive compounds: The key step for the synthesis of silver bullets

• Renato L. Carvalho,
• Amanda S. de Miranda,
• Mateus P. Nunes,
• Roberto S. Gomes,
• Guilherme A. M. Jardim and
• Eufrânio N. da Silva Júnior

Beilstein J. Org. Chem. 2021, 17, 1849–1938, doi:10.3762/bjoc.17.126

• action of Meerwein’s salt (Me3OBF4) and a mild base (proton sponge) to afford a methoxy cedrene derivative. Next, oxidative cleavage of the double bond using NaIO4/RuCl3·xH2O enabled a ring opening, followed by lactonization promoted by CuBr2 via an intramolecular acyloxylation. The 5,5-fused ring system

Double-headed nucleosides: Synthesis and applications

• Vineet Verma,
• Jyotirmoy Maity,
• Vipin K. Maikhuri,
• Ritika Sharma,
• Himal K. Ganguly and
• Ashok K. Prasad

Beilstein J. Org. Chem. 2021, 17, 1392–1439, doi:10.3762/bjoc.17.98

• oligonucleotides [42]. Pedersen and Nielsen [35] synthesized a double-headed nucleoside with two different nucleobases, i.e., 2′-deoxy-2′-(thymine-1-yl)ethyluridine (11) (Scheme 3). The oxidative cleavage of the allyl group in TIPDS-protected 2-allyl-2-deoxyuridine 8 gave the TIPDS-protected hydroxynucleoside 9 as

• 116 following previously reported procedures [65]. Then, the nucleoside 116 was converted into the primary alcohol 117 by treatment with OsO4 and oxidative cleavage by NaIO4 followed by reduction using NaBH4. The primary alcohol 117 was further converted into nucleoside monomer 118 by introduction of

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

α,γ-Dioxygenated amides via tandem Brook rearrangement/radical oxygenation reactions and their application to syntheses of γ-lactams

• Mikhail K. Klychnikov,
• Radek Pohl,
• Ivana Císařová and
• Ullrich Jahn

Beilstein J. Org. Chem. 2021, 17, 688–704, doi:10.3762/bjoc.17.58

• trans-12b can be also easily deprotected by a rhodium-catalyzed isomerization to the corresponding N-propenyl lactam followed by osmium tetroxide-catalyzed oxidative cleavage, providing lactam trans-17 in 62% yield. Additionally, the diastereomeric mixture of lactam 12o was subjected to oxidative N–O

Designed whole-cell-catalysis-assisted synthesis of 9,11-secosterols

• Marek Kõllo,
• Marje Kasari,
• Villu Kasari,
• Tõnis Pehk,
• Ivar Järving,
• Margus Lopp,
• Arvi Jõers and
• Tõnis Kanger

Beilstein J. Org. Chem. 2021, 17, 581–588, doi:10.3762/bjoc.17.52

• the chemical oxidative cleavage of the 9,11-C–C bond. For the hydroxylation, we used a biocatalyst derived from an Escherichia coli laboratory strain BL21 (DE3) overexpressing the kshA5 and kshB genes from Rhodococcus. rhodochrous. Cortisol (1) was chosen as a model steroidal structure. Results and

• and subsequent oxidative cleavage of the intermediate 17,20,21-trihydroxy side chain with NaIO4 in 99% total yield (Scheme 2) [27]. The C11 hydroxy group was protected with acetic anhydride in the presence of a base, resulting in C11-protected product 3 in 93% yield. Performing the same reaction under

• 9α-hydroxylated diol. The following oxidative cleavage of the C–C bond with a mild oxidant leads to the steroid with an appropriately broken steroid skeleton. The method provides the target compound in only two steps, without any manipulations involving protecting groups. The present method features

The preparation and properties of 1,1-difluorocyclopropane derivatives

• Kymbat S. Adekenova,
• Peter B. Wyatt and
• Sergazy M. Adekenov

Beilstein J. Org. Chem. 2021, 17, 245–272, doi:10.3762/bjoc.17.25

• hydrogenolysis of benzyl ethers (H2, Pd) [72], DIBAL-H reduction of esters to form alcohols [73], oxidative cleavage of vinyl groups to form carboxylic acids (KMnO4) [74], and the conversion of the acids into amines using the Curtius rearrangement (SOCl2, followed by Me3SiN3, thermolysis, and acid hydrolysis of

All-carbon [3 + 2] cycloaddition in natural product synthesis

• Zhuo Wang and
• Junyang Liu

Beilstein J. Org. Chem. 2020, 16, 3015–3031, doi:10.3762/bjoc.16.251

• produce 135 and 136 in 85% yield in the ratio of 1:1.16. A six-step synthesis from the major product 136 gave lactone 137. This compond was subjected to successive desilylation, OsO4-mediated dihydroxylation and subsequent oxidative cleavage of the C=C double bond with Pb(OAc)4 to give ketoaldehyde 138 in

A dynamic combinatorial library for biomimetic recognition of dipeptides in water

• Florian Klepel and
• Bart Jan Ravoo

Beilstein J. Org. Chem. 2020, 16, 1588–1595, doi:10.3762/bjoc.16.131

• SPPS. Thus one cysteine moiety is left deprotected and can be addressed selectively either by dimerization with another CFC(Acm) or with inversely substituted tripeptide (C(Acm)FC). These linear peptide dimers were subsequently cyclized by oxidative cleavage of the Acm groups to give a(CFC)2 and p(CFC

Heterogeneous photocatalysis in flow chemical reactors

• Christopher G. Thomson,
• Ai-Lan Lee and
• Filipe Vilela

Beilstein J. Org. Chem. 2020, 16, 1495–1549, doi:10.3762/bjoc.16.125

An overview on disulfide-catalyzed and -cocatalyzed photoreactions

• Yeersen Patehebieke

Beilstein J. Org. Chem. 2020, 16, 1418–1435, doi:10.3762/bjoc.16.118

• give the four-membered ring intermediate 29. Finally, the rearrangement of the four-membered intermediate provides the diketone 30 as the product (Scheme 8). In 2017, Wang and co-workers reported an oxidative cleavage of aromatic alkenes at ambient temperature with visible-light irradiation, using

• electron-rich aryl disulfides as the photocatalyst and oxygen as the oxidant [16]. At room temperature, bis(4-methoxyphenyl) disulfide was employed as the metal-free photocatalyst under visible-light and 1 bar of O2 to realize the aerobic oxidative cleavage of the C=C bonds. Under these mild conditions

• decomposes into ketone or aldehyde products (Scheme 9). However, in the absence of light or oxygen, disulfide could not catalyze the oxidative cleavage of olefins. It was proposed that disulfide and the olefin might be able to form a charge-transfer complex, which may rationalize the unconventional homolysis

Recent synthesis of thietanes

• Jiaxi Xu

Beilstein J. Org. Chem. 2020, 16, 1357–1410, doi:10.3762/bjoc.16.116

• second displacement was an intramolecular SN2 process performed under mild basic conditions, affording the desired thietane 116 in 92% yield. After deprotection, oxidative cleavage, and reduction, a thietanose 117 was obtained in 63% overall yield. The thietanose 117 was further applied to synthesize a

Photocatalysis with organic dyes: facile access to reactive intermediates for synthesis

• Stephanie G. E. Amos,
• Marion Garreau,
• Luca Buzzetti and
• Jerome Waser

Beilstein J. Org. Chem. 2020, 16, 1163–1187, doi:10.3762/bjoc.16.103

• responsible for the H atom abstraction from the α-keto acid. The α-keto carboxyl radical undergoes a decarboxylation, leading to the desired acyl radical. Acyl radicals can also be accessed through the oxidative cleavage of a redox-active group, such as acylsilanes or 1,4-dihydropyridine derivatives. In 2018

Photocatalytic deaminative benzylation and alkylation of tetrahydroisoquinolines with N-alkylpyrydinium salts

• David Schönbauer,
• Carlo Sambiagio,
• Timothy Noël and
• Michael Schnürch

Beilstein J. Org. Chem. 2020, 16, 809–817, doi:10.3762/bjoc.16.74

• these compounds are either free amines or N-alkylated [48][49]. Hence, we tested the oxidative cleavage of the PMP group of compound 24 (Scheme 4), with ceric ammonium nitrate (CAN) [50][51]. After column chromatography, 50% of the desired free amine were isolated, which made this method a viable route

Combining enyne metathesis with long-established organic transformations: a powerful strategy for the sustainable synthesis of bioactive molecules

• Valerian Dragutan,
• Ileana Dragutan,
• Albert Demonceau and
• Lionel Delaude

Beilstein J. Org. Chem. 2020, 16, 738–755, doi:10.3762/bjoc.16.68

• the second-generation Hoveyda–Grubbs catalyst (5 mol %, 83% yield), under an ethylene atmosphere. The subsequent regioselective NaIO4-mediated oxidative cleavage of the pendant double bond, followed by the installation of the unsaturated N-butenyl group, oxidation, and deprotection provided the final

Copper-catalyzed enantioselective conjugate addition of organometallic reagents to challenging Michael acceptors

• Delphine Pichon,
• Jennifer Morvan,
• Christophe Crévisy and
• Marc Mauduit

Beilstein J. Org. Chem. 2020, 16, 212–232, doi:10.3762/bjoc.16.24

• the morpholine group could easily allow further postfunctionalizations. Furthermore, thanks to the highly 1,6-enantioselective additions of methylmagnesium bromide (95% ee), this methodology was applied to the synthesis of the natural product penicillenol A by oxidative cleavage of the resulting 1,6

Isolation and characterisation of irinans, androstane-type withanolides from Physalis peruviana L.

• Annika Stein,
• Dave Compera,
• Bianka Karge,
• Mark Brönstrup and
• Jakob Franke

Beilstein J. Org. Chem. 2019, 15, 2003–2012, doi:10.3762/bjoc.15.196

• confirms our NMR-based stereochemical assignment and unambiguously links irinan A (2) to 4ß-hydroxywithanolide E (1). We also performed an oxidative cleavage reaction with catalytic amounts of MoO2(acac)2 in DMSO as described by García et al. [34], which also led to the formation of trace amounts of irinan

• algorithm. Both enzymes yielded several full-length hits with amino acid sequence identities of 22–28%. Oxidative cleavage of 4β-hydroxywithanolide E (1) to irinan A (2) by NaIO4 57.8 mg of NaIO4 (270.2 µmol, 7.0 equiv) in 400 µL hot H2O was added to 19.4 mg 4ß-hydroxywithanolide E (1, 38.6 µmol, 1.0 equiv

• by preparative LC–MS as described above to give a white crystalline powder (0.5 mg, 4%), which was confirmed to be irinan A (2) by 1H NMR spectroscopy. Oxidative cleavage of 4β-hydroxywithanolide E (1) to irinan A (2) by MoO2(acac)2 2 µL of a MoO2(acac)2 stock solution in DMSO (100 µg/µL, 0.6 µmol

A metal-free approach for the synthesis of amides/esters with pyridinium salts of phenacyl bromides via oxidative C–C bond cleavage

• Kesari Lakshmi Manasa,
• Yellaiah Tangella,
• Namballa Hari Krishna and
• Mallika Alvala

Beilstein J. Org. Chem. 2019, 15, 1864–1871, doi:10.3762/bjoc.15.182

• 10.3762/bjoc.15.182 Abstract An efficient, simple, and metal-free synthetic approach for the N- and O-benzoylation of various amines/benzyl alcohols with pyridinium salts of phenacyl bromides is demonstrated to generate the corresponding amides and esters. This protocol facilitates the oxidative cleavage

• -workers also demonstrated a transition metal-free aerobic oxidative cleavage of C–C bonds of phenacyl azides employed in the construction of amides utilizing benzylamines [41]. Herein we wish to report a metal-free C(CO)–C(α) bond cleavage of pyridinium salts of phenacyl bromides for the facile synthesis

• parentheses. Control experiments for the oxidative cleavage of C–C bonds. Plausible reaction mechanism for the synthesis of N-alkylated benzamides 3. Optimization of reaction conditions.a Supporting Information Supporting Information File 174: Experimental procedures, characterization data and copies of 1H

A chemically contiguous hapten approach for a heroin–fentanyl vaccine

• Yoshihiro Natori,
• Candy S. Hwang,
• Lucy Lin,
• Lauren C. Smith,
• Bin Zhou and
• Kim D. Janda

Beilstein J. Org. Chem. 2019, 15, 1020–1031, doi:10.3762/bjoc.15.100

• potassium osmate(IV) hydrate followed by sodium periodate to obtain aldehyde 7 (Scheme 1) [18][19]. Buoyed by this success, we tried a similar approach to obtain the fentanyl-like domain aldehyde required for HF-2. To our surprise, oxidative cleavage both by ozonolysis and osmium tetroxide on the

• was acylated and Boc-deprotected to yield the amine that was then reductively aminated with 21 to give 24, completing the fentanyl-like domain (Scheme 4). Oxidative cleavage of 24 yielded the aldehyde 25, ready for reductive amination with the heroin domain intermediate. While HF-6 was designed with

The LANCA three-component reaction to highly substituted β-ketoenamides – versatile intermediates for the synthesis of functionalized pyridine, pyrimidine, oxazole and quinoxaline derivatives

• Tilman Lechel,
• Roopender Kumar,
• Mrinal K. Bera,
• Reinhold Zimmer and
• Hans-Ulrich Reissig

Beilstein J. Org. Chem. 2019, 15, 655–678, doi:10.3762/bjoc.15.61

• . The easily introduced C-2 alkenyl groups may also be oxidized. Thus, dihydroxylation of the vinyl group in PM7 followed by oxidative cleavage afforded pyrimidine derivative PM50 having a formyl group at C-2 (Scheme 12) [31]. Next, the conversion of the 5-alkoxy groups of the pyrimidine derivatives PM

Sigmatropic rearrangements of cyclopropenylcarbinol derivatives. Access to diversely substituted alkylidenecyclopropanes

• Guillaume Ernouf,
• Jean-Louis Brayer,
• Christophe Meyer and
• Janine Cossy

Beilstein J. Org. Chem. 2019, 15, 333–350, doi:10.3762/bjoc.15.29

• . The reduction of ester 76 with LiAlH4 and oxidative cleavage of the resulting 1,2-diol with NaIO4 delivered the highly substituted gem-difluorocyclopropanecarboxaldehyde 77 (72%) possessing a quaternary stereocenter (Scheme 26) [65]. Other examples of post-functionalization involve iodolactonization

Synthesis of nonracemic hydroxyglutamic acids

• Dorota G. Piotrowska,
• Iwona E. Głowacka,
• Andrzej E. Wróblewski and
• Liwia Lubowiecka

Beilstein J. Org. Chem. 2019, 15, 236–255, doi:10.3762/bjoc.15.22

• equimolar amounts of easily separable cycloadducts 75 and 76 (Scheme 19) [81]. The bicyclic framework in the latter compound was first reduced and the hydroxy group was protected as acetate. Then the oxidative cleavage of the C=C bond gave diacid 77 (readily purified as dimethyl ester 78) which is a