Metal-free mechanochemical oxidations in Ertalyte^® jars

• Andrea Porcheddu,
• Francesco Delogu,
• Lidia De Luca,
• Claudia Fattuoni and
• Evelina Colacino

Beilstein J. Org. Chem. 2019, 15, 1786–1794, doi:10.3762/bjoc.15.172

• a mechanochemical process. Keywords: AZADO; Ertalyte®; green chemistry; mechanochemistry; NaOCl·5H2O; selective oxidation; TEMPO; Introduction The conversion of primary and secondary alcohols to the corresponding carbonyl compounds (aldehydes and ketones, respectively) is of such importance in

• the atom efficiency [4][5]. The discovery of (2,2,6,6-tetramethylpiperidin-1-yl)oxyl, commonly known as TEMPO by Lebedev and Kazarnowskii in 1960 has been hailed as a significant breakthrough in the field of redox reactions, allowing the fast and selective oxidation of alcohols to the related carbonyl

• synthetic route that can be scaled up to pilot and industrial levels. Results and Discussion Since the most commonly employed oxidizing agents are solid reagents, we decided to develop an efficient and eco-friendly process for the selective oxidation of alcohols to the corresponding aldehydes/ketones based

Diastereo- and enantioselective preparation of cyclopropanol derivatives

• Marwan Simaan and
• Ilan Marek

Beilstein J. Org. Chem. 2019, 15, 752–760, doi:10.3762/bjoc.15.71

• cyclopropylmagnesium species 6MgBr, the selective oxidation reaction of the copper species, resulting from a transmetalation reaction, was similarly achieved by reaction with oxenoid [71][79][80][86][87][88][89]. In all cases, cyclopropanols 7 were obtained as single diastereoisomer (dr 98:2:0:0) with excellent

Selective benzylic C–H monooxygenation mediated by iodine oxides

• Kelsey B. LaMartina,
• Haley K. Kuck,
• Linda S. Oglesbee,
• Asma Al-Odaini and
• Nicholas C. Boaz

Beilstein J. Org. Chem. 2019, 15, 602–609, doi:10.3762/bjoc.15.55

• hypervalent iodine species as a terminal oxidant. Combinations of ammonium iodate and catalytic N-hydroxyphthalimide (NHPI) were shown to be effective in the selective oxidation of n-butylbenzene directly to 1-phenylbutyl acetate in high yield (86%). This method shows moderate substrate tolerance in the

Thiol-free chemoenzymatic synthesis of β-ketosulfides

• Adrián A. Heredia,
• Martín G. López-Vidal,
• Marcela Kurina-Sanz,
• Fabricio R. Bisogno and
• Alicia B. Peñéñory

Beilstein J. Org. Chem. 2019, 15, 378–387, doi:10.3762/bjoc.15.34

• temperature one-pot two-step preparation of the phenacyl allyl sulfide 2h. cIsolated yield. Selective oxidation of the β-ketosulfide 2a. Screening of hydrolases and conditions towards a model substrate.a Lipase-catalysed hydrolysis–protonation sequence over a series of β-thioalkyl enol esters.a Supporting

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

• nitrogen was protected as N-Boc to furnish (4R,5R)-47. Under basic conditions the pyrrolidin-2-one ring was cleaved to provide a five-carbon chain of the target molecule. The final steps included esterification, desilylation and selective oxidation of the hydroxymethyl group followed by esterification

Applications of organocatalysed visible-light photoredox reactions for medicinal chemistry

• Michael K. Bogdos,
• Emmanuel Pinard and
• John A. Murphy

Beilstein J. Org. Chem. 2018, 14, 2035–2064, doi:10.3762/bjoc.14.179

• such a mild and selective oxidation. MacMillan and co-workers have recently developed a method for the bioconjugation of peptides by radical decarboxylation of the C-terminus of peptides and subsequent Giese-type addition to Michael acceptors. This is performed under blue light irradiation, using

Preparation and X-ray structure of 2-iodoxybenzenesulfonic acid (IBS) – a powerful hypervalent iodine(V) oxidant

• Irina A. Mironova,
• Pavel S. Postnikov,
• Rosa Y. Yusubova,
• Akira Yoshimura,
• Thomas Wirth,
• Viktor V. Zhdankin,
• Victor N. Nemykin and
• Mekhman S. Yusubov

Beilstein J. Org. Chem. 2018, 14, 1854–1858, doi:10.3762/bjoc.14.159

• product of its acetylation Dess–Martin periodinane (DMP) are the most common oxidants used for selective oxidation of alcohols to carbonyl compounds as well as for a variety of other synthetically useful oxidative transformations [10][11]. IBX and DMP are mild oxidants with a relatively low reactivity

Cobalt–metalloid alloys for electrochemical oxidation of 5-hydroxymethylfurfural as an alternative anode reaction in lieu of oxygen evolution during water splitting

• Jonas Weidner,
• Stefan Barwe,
• Kirill Sliozberg,
• Stefan Piontek,
• Justus Masa,
• Ulf-Peter Apfel and
• Wolfgang Schuhmann

Beilstein J. Org. Chem. 2018, 14, 1436–1445, doi:10.3762/bjoc.14.121

• comparatively lower potential than that required for water oxidation. Suitable catalysts are, however, required to achieve a selective oxidation of HMF to FDCA with a high conversion yield. We recently demonstrated that the modification of cobalt with boron and phosphorus alters the electronic and lattice

Biocatalytic synthesis of the Green Note trans-2-hexenal in a continuous-flow microreactor

• Morten M. C. H. van Schie,
• Tiago Pedroso de Almeida,
• Gabriele Laudadio,
• Florian Tieves,
• Elena Fernández-Fueyo,
• Timothy Noël,
• Isabel W. C. E. Arends and
• Frank Hollmann

Beilstein J. Org. Chem. 2018, 14, 697–703, doi:10.3762/bjoc.14.58

• selective oxidation of trans-hex-2-enol. A: Alcohol dehydrogenase (ADH)-catalysed oxidation producing stoichiometric amounts of NAD(P)H, which needs to be recycled in situ; the overall reaction is reversible requiring surpluses of the cosubstrate (e.g., acetone) to shift the overall equilibrium to the side

Latest development in the synthesis of ursodeoxycholic acid (UDCA): a critical review

• Fabio Tonin and
• Isabel W. C. E. Arends

Beilstein J. Org. Chem. 2018, 14, 470–483, doi:10.3762/bjoc.14.33

• . Ideally, there is the possibility of using other types of less volatile compounds but no reports thereof have been found. 12α-Hydroxysteroid dehydrogenase 12α-Hydroxysteroid dehydrogenases (12α-HSDH) are particularly interesting for the selective oxidation of the 12-hydroxy group of CA (Figure 4). These

• ][67][68][69][70]. Examples of processes for the selective oxidation of bile acids, their salts or derivatives were patented [71][72]. In addition to these reported biotransformations, many additional 7α-HSDHs have been discovered and reported over the past years. About 500 entries can be found in

Photocatalytic formation of carbon–sulfur bonds

• Alexander Wimmer and
• Burkhard König

Beilstein J. Org. Chem. 2018, 14, 54–83, doi:10.3762/bjoc.14.4

• , respectively. Radical cross-coupling with the thiosulfate salt forms a sulfide radical anion, which is oxidized to the respective sulfide adduct by regeneration Eosin Y. This sulfide-forming step counts also for the sulfoxidation reaction. However, selective oxidation of the sulfide to the respective sulfoxide

• is accomplished by in situ generated singlet oxygen, which is generated by energy-transfer of the excited state of Eosin Y and only possible under aerobic conditions. The authors also found that zinc acetate is beneficial for the selective oxidation. A series of electron-rich and electron-poor

Mechanically induced oxidation of alcohols to aldehydes and ketones in ambient air: Revisiting TEMPO-assisted oxidations

• Andrea Porcheddu,
• Evelina Colacino,
• Giancarlo Cravotto,
• Francesco Delogu and
• Lidia De Luca

Beilstein J. Org. Chem. 2017, 13, 2049–2055, doi:10.3762/bjoc.13.202

• ]. Although the literature provides a plethora of generic indications and detailed recipes on this subject [7][8][9][10], the selective oxidation of primary alcohols to the corresponding aldehydes is one of the most difficult transformations to control because of the marked propensity towards over-oxidation

• catalyst for the selective oxidation of primary alcohols to aldehydes under ambient aerobic conditions (Scheme 1) [25][26]. The procedure is operationally simple and extremely effective in terms of both chemoselectivity and reaction yield [27][28]. Gao (2016) further improved this methodology by replacing

• to the selective oxidation of alcohols to aldehydes. Specifically, we investigated the potential of a mechanically activated TEMPO-based oxidative procedure [64]. Results and Discussion We began our investigation with an attempt to replicate Gao’s procedure in a stainless steel reactor of a

New bio-nanocomposites based on iron oxides and polysaccharides applied to oxidation and alkylation reactions

• Daily Rodríguez-Padrón,
• Alina M. Balu,
• Antonio A. Romero and
• Rafael Luque

Beilstein J. Org. Chem. 2017, 13, 1982–1993, doi:10.3762/bjoc.13.194

• assessed in the alkylation reaction of toluene with benzyl chloride and the selective oxidation of benzyl alcohol to benzaldehyde. X-ray diffraction The structure and arrangement of the synthesized materials were analyzed by X-ray diffraction. The XRD pattern of the Fe2O3-PS4 nanomaterial exhibited a

• these catalysts as potential candidates in both the selective oxidation of benzyl alcohol and alkylation of toluene with benzyl chloride. Experimental Synthesis of bio-nanocomposites based on iron oxide and polysaccharide S4 A simple, reproducible and environmentally friendly protocol has been developed

The chemistry and biology of mycolactones

• Matthias Gehringer and
• Karl-Heinz Altmann

Beilstein J. Org. Chem. 2017, 13, 1596–1660, doi:10.3762/bjoc.13.159

• secondary TES and the primary TBS ether protecting groups was followed by selective oxidation of the ensuing primary alcohol to deliver seco acid 27. The crucial macrolactonization was performed under Yamaguchi conditions [135] in 70% yield and subsequent cleavage of the secondary TBS ether under mildly

Urea–hydrogen peroxide prompted the selective and controlled oxidation of thioglycosides into sulfoxides and sulfones

• Adesh Kumar Singh,
• Varsha Tiwari,
• Kunj Bihari Mishra,
• Surabhi Gupta and
• Jeyakumar Kandasamy

Beilstein J. Org. Chem. 2017, 13, 1139–1144, doi:10.3762/bjoc.13.113

• .) [34]. Therefore, the scope of this methodology was further investigated with oxidation of allyl group protected thioglycoside 14 (Table 2, entry 14). Remarkably, allyl groups were found to be very stable during the oxidation while sulfide underwent selective oxidation to corresponding sulfoxide and

Synthesis of 1-indanones with a broad range of biological activity

• Marika Turek,
• Dorota Szczęsna,
• Marek Koprowski and
• Piotr Bałczewski

Beilstein J. Org. Chem. 2017, 13, 451–494, doi:10.3762/bjoc.13.48

Highly bulky and stable geometry-constrained iminopyridines: Synthesis, structure and application in Pd-catalyzed Suzuki coupling of aryl chlorides

• Yi Lai,
• Zhijian Zong,
• Yujie Tang,
• Weimin Mo,
• Nan Sun,
• Baoxiang Hu,
• Zhenlu Shen,
• Liqun Jin,
• Wen-hua Sun and
• Xinquan Hu

Beilstein J. Org. Chem. 2017, 13, 213–221, doi:10.3762/bjoc.13.24

• Yi Lai Zhijian Zong Yujie Tang Weimin Mo Nan Sun Baoxiang Hu Zhenlu Shen Liqun Jin Wen-hua Sun Xinquan Hu College of Chemical Engineering, Zhejiang University of Technology, Hangzhou 310032, P.R. China State Key Laboratory for Oxo Synthesis and Selective Oxidation, Lanzhou Institute of Chemical

Total synthesis of a Streptococcus pneumoniae serotype 12F CPS repeating unit hexasaccharide

• Peter H. Seeberger,
• Claney L. Pereira and
• Subramanian Govindan

Beilstein J. Org. Chem. 2017, 13, 164–173, doi:10.3762/bjoc.13.19

• -azidomannose moiety of 46 was converted to the corresponding mannosaminuronic acid by cleaving the C6 benzoate ester using sodium methoxide in methanol and selective oxidation of the primary alcohol of 47 using BAIB/TEMPO. Tetrasaccharide acceptor 48 was obtained by esterification of the carboxylic acid under

Stereo- and regioselectivity of the hetero-Diels–Alder reaction of nitroso derivatives with conjugated dienes

• Lucie Brulíková,
• Aidan Harrison,
• Marvin J. Miller and
• Jan Hlaváč

Beilstein J. Org. Chem. 2016, 12, 1949–1980, doi:10.3762/bjoc.12.184

• Scheme 5). More recently, the method was extended to the mild copper-catalyzed aerobic oxidation of hydroxylamines [48][49][50]. In 2014, the Lykakis group reported the selective oxidation of various arylamines into the corresponding nitrosoarenes through polyoxometalate anions supported on mesoporous

Synthesis and properties of fluorescent 4′-azulenyl-functionalized 2,2′:6′,2″-terpyridines

• Adrian E. Ion,
• Liliana Cristian,
• Mariana Voicescu,
• Masroor Bangesh,
• Augustin M. Madalan,
• Daniela Bala,
• Constantin Mihailciuc and
• Simona Nica

Beilstein J. Org. Chem. 2016, 12, 1812–1825, doi:10.3762/bjoc.12.171

• development of an efficient ruthenium catalyst for selective oxidation of both aliphatic and aromatic amines to nitriles [22]. The catalytic effectiveness of this ruthenium terpyridine complex was ascribed to the polarization effect of the azulene moiety attached at the terpyridine unit and it was sustained

Synthesis of the C8’-epimeric thymine pyranosyl amino acid core of amipurimycin

• Pramod R. Markad,
• Navanath Kumbhar and
• Dilip D. Dhavale

Beilstein J. Org. Chem. 2016, 12, 1765–1771, doi:10.3762/bjoc.12.165

• generated stereocenters, we continued our synthesis with anhydrosugar 12 as its configurations are matching with that of target compound. Thus, TEMPO-mediated selective oxidation of the primary hydroxy group in 12 to acid functionality followed by esterification using diazomethane afforded azido methyl

From steroids to aqueous supramolecular chemistry: an autobiographical career review

• Bruce C. Gibb

Beilstein J. Org. Chem. 2016, 12, 684–701, doi:10.3762/bjoc.12.69

Regiodefined synthesis of brominated hydroxyanthraquinones related to proisocrinins

• Joyeeta Roy,
• Tanushree Mal,
• Supriti Jana and
• Dipakranjan Mal

Beilstein J. Org. Chem. 2016, 12, 531–536, doi:10.3762/bjoc.12.52

• at δ 111.7 ppm in the 13C NMR spectrum. The Michael acceptor 13 was prepared according to the literature procedure starting from cyclohex-3-enecarbaldehyde (25) [38]. The diol 26 was oxidized with activated MnO2, leading to selective oxidation of the secondary alcohol forming 27 in 83% yield. The

• lactol 34 with methylmagnesium bromide afforded diol 35 in 72% yield. Selective oxidation of the allylic alcohol group in 35 with MnO2, followed by acetylation of the secondary hydroxy group with acetyl chloride, triethylamine and DMAP furnished cyclohexenone 36 (Scheme 5). The Hauser annulation of

Synthesis of bi- and bis-1,2,3-triazoles by copper-catalyzed Huisgen cycloaddition: A family of valuable products by click chemistry

• Zhan-Jiang Zheng,
• Ding Wang,
• Zheng Xu and
• Li-Wen Xu

Beilstein J. Org. Chem. 2015, 11, 2557–2576, doi:10.3762/bjoc.11.276

• Selective Oxidation, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou, P. R. China 10.3762/bjoc.11.276 Abstract The Cu(I)-catalyzed azide-alkyne cycloaddition reaction, also known as click chemistry, has become a useful tool for the facile formation of 1,2,3-triazoles

Active site diversification of P450cam with indole generates catalysts for benzylic oxidation reactions

• Paul P. Kelly,
• Anja Eichler,
• Susanne Herter,
• David C. Kranz,
• Nicholas J. Turner and
• Sabine L. Flitsch

Beilstein J. Org. Chem. 2015, 11, 1713–1720, doi:10.3762/bjoc.11.186

• domain of P450-RhF (RhFRed) [17][18][19]. This chimera, named P450cam-RhFRed, operates without the need for additional reductase partners and retains the native activity of non-fused P450cam in the selective oxidation of camphor to 5-exo-hydroxycamphor. When generated as a whole-cell biocatalyst in