One-pot synthesis of isosorbide from cellulose or lignocellulosic biomass: a challenge?

• Isaline Bonnin,
• Raphaël Mereau,
• Thierry Tassaing and
• Karine De Oliveira Vigier

Beilstein J. Org. Chem. 2020, 16, 1713–1721, doi:10.3762/bjoc.16.143

• increased production of insoluble byproducts. The productivity of isosorbide can reach 40.2 g·L−1·h−1with a purity of 73%. The recycling of the metal-supported catalyst (Ru/C) was studied and a high catalytic activity decrease was observed after the first run, showing that the catalyst was not recyclable

• are used with low concentration, a reduced salt will be formed after the neutralization step. Moreover, heteropolyacids can be precipitated via ion exchange with larger cations, e.g., K+, Cs+ and NH4+, or in certain cases even extracted to allow direct recycling. Thus, the usage of heterogeneous acid

• differs (2.6 nm for 2% Ru/C and 5.3 nm for 4% Ru/C) suggesting that the Ru species formed in the 4 w. % Ru/C catalyst are more active for conversion of cellulose into isosorbide. The recycling of 4 wt % Ru/C and Amberlyst 70 catalysts was studied at different temperatures. At all the temperatures studied

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

• led to great progress within the last decade, with new HPCat materials and reactor designs beginning to shift the photocatalysis paradigms towards HPCats because of their advantages of reduced purification and facile recycling. 1.3 Benefits of heterogeneous photocatalysts in flow In addition to

• separation and recycling, HPCats show advantages such as an enhanced photostability and selectivity [47][48]. A heterogeneous catalyst with a high surface area is often associated with a greater number of surface-active sites for catalysis to occur and makes morphological control critical to the catalyst

Activated carbon as catalyst support: precursors, preparation, modification and characterization

• Melanie Iwanow,
• Tobias Gärtner,
• Volker Sieber and
• Burkhard König

Beilstein J. Org. Chem. 2020, 16, 1188–1202, doi:10.3762/bjoc.16.104

Recent advances in Cu-catalyzed C(sp³)–Si and C(sp³)–B bond formation

• Balaram S. Takale,
• Ruchita R. Thakore,
• Elham Etemadi-Davan and
• Bruce H. Lipshutz

Beilstein J. Org. Chem. 2020, 16, 691–737, doi:10.3762/bjoc.16.67

• , provided an opportunity for recycling and reuse. This catalyst, therefore, was isolated using simple centrifugation and reused in a second reaction leading to no appreciable loss in catalytic activity en route to product 218. It was also utilized not only for unsaturated ketones but also to deliver the

Photophysics and photochemistry of NIR absorbers derived from cyanines: key to new technologies based on chemistry 4.0

• Bernd Strehmel,
• Christian Schmitz,
• Ceren Kütahya,
• Yulian Pang,
• Anke Drewitz and
• Heinz Mustroph

Beilstein J. Org. Chem. 2020, 16, 415–444, doi:10.3762/bjoc.16.40

Six-fold C–H borylation of hexa-peri-hexabenzocoronene

• Mai Nagase,
• Kenta Kato,
• Akiko Yagi,
• Yasutomo Segawa and
• Kenichiro Itami

Beilstein J. Org. Chem. 2020, 16, 391–397, doi:10.3762/bjoc.16.37

• . HBC (sublimated) was purchased from FUJIFILM Wako Pure Chemical Corporation (Catalog No. W01N40HZ370). Compound 2 was synthesized according to a reported procedure [23]. Flash column chromatography was performed with KANTO Silica Gel 60N (spherical, neutral, 40–100 µm). Preparative recycling gel

Architecture and synthesis of P,N-heterocyclic phosphine ligands

• Wisdom A. Munzeiwa,
• Bernard Omondi and
• Vincent O. Nyamori

Beilstein J. Org. Chem. 2020, 16, 362–383, doi:10.3762/bjoc.16.35

• applicability of the catalysts in two-phase homogeneous catalysis because it allows easy recycling [85] and separation from the reaction mixture [8]. Carbon–halogen bonds are more activated than carbon–hydrogen bonds and hence the halogen is more labile and preferentially displaced. Brill et al. [86] took

Oligomeric ricinoleic acid preparation promoted by an efficient and recoverable Brønsted acidic ionic liquid

• Fei You,
• Xing He,
• Song Gao,
• Hong-Ru Li and
• Liang-Nian He

Beilstein J. Org. Chem. 2020, 16, 351–361, doi:10.3762/bjoc.16.34

• dehydration esterification of ricinoleic acid and catalyst recycling The dehydration esterification of ricinoleic acid was investigated using ILs as catalyst. In a typical run, 10 g (30 mmol) ricinoleic acid and 1 g (2.6 mmol) [HSO3-BDBU]H2PO4 were added into a 100 mL glass flask equipped with magnetic

Efficient method for propargylation of aldehydes promoted by allenylboron compounds under microwave irradiation

• Jucleiton J. R. Freitas,
• Queila P. S. B. Freitas,
• Silvia R. C. P. Andrade,
• Juliano C. R. Freitas,
• Roberta A. Oliveira and
• Paulo H. Menezes

Beilstein J. Org. Chem. 2020, 16, 168–174, doi:10.3762/bjoc.16.19

• factor) [31]. Within this context, the development of solvent-free methods is highly desirable since the difficult for solvent recycling in academic laboratories and chemical manufacturing plants is universal. In addition, a reliable method for the propargylation reaction which could involve the use of

Synthesis of 3-alkenylindoles through regioselective C–H alkenylation of indoles by a ruthenium nanocatalyst

• Abhijit Paul,
• Debnath Chatterjee,
• Srirupa Banerjee and
• Somnath Yadav

Beilstein J. Org. Chem. 2020, 16, 140–148, doi:10.3762/bjoc.16.16

• tolerated several functional groups, including bromine and nitrile units, which provide ample scope for further manipulation of the products from the perspective of medicinal chemistry. The catalyst can be easily recovered and recycled in a colloidal solid form, enabling catalytic recycling and reusability

A review of asymmetric synthetic organic electrochemistry and electrocatalysis: concepts, applications, recent developments and future directions

• Munmun Ghosh,
• Valmik S. Shinde and
• Magnus Rueping

Beilstein J. Org. Chem. 2019, 15, 2710–2746, doi:10.3762/bjoc.15.264

• ). In 2007, Schmid explored the application of Rh complex 141 as a mediator for NADPH recycling [80]. This report showed that asymmetric electroreduction of cyclohexanone 140 in organic/aqueous media can be efficiently catalyzed by thermophilic NAD-dependent alcohol dehydrogenase (TADH) and result in

Nanopatterns of arylene–alkynylene squares on graphite: self-sorting and intercalation

• Tristan J. Keller,
• Joshua Bahr,
• Kristin Gratzfeld,
• Nina Schönfelder,
• Marcin A. Majewski,
• Marcin Stępień,
• Sigurd Höger and
• Stefan-S. Jester

Beilstein J. Org. Chem. 2019, 15, 1848–1855, doi:10.3762/bjoc.15.180

• protective groups [28]. Subsequently, 1a/b were prepared by Pd-catalyzed oxidative cyclodimerization of the respective acetylene-terminated precursors under high-dilution conditions [29][30]. The separation of the crude products by recycling gel permeation chromatography (recGPC) yielded the monodisperse

Vicinal difunctionalization of alkenes by four-component radical cascade reaction of xanthogenates, alkenes, CO, and sulfonyl oxime ethers

• Shuhei Sumino,
• Takahide Fukuyama,
• Mika Sasano,
• Ilhyong Ryu,
• Antoine Jacquet,
• Frédéric Robert and
• Yannick Landais

Beilstein J. Org. Chem. 2019, 15, 1822–1828, doi:10.3762/bjoc.15.176

• Gel 60N (spherical, neutral, 40–50 μm)) and, if necessary, were further purified by recycling preparative HPLC (Japan Analytical Industry Co. Ltd., LC-918) equipped with GPC columns (JAIGEL-1H + JAIGEL-2H columns) using CHCl3 as eluent. Xanthogenate 1a,b [20], 1c [36], alkene 2c [37], and oxime ester

A heteroditopic macrocycle as organocatalytic nanoreactor for pyrroloacridinone synthesis in water

• Piyali Sarkar,
• Sayan Sarkar and
• Pradyut Ghosh

Beilstein J. Org. Chem. 2019, 15, 1505–1514, doi:10.3762/bjoc.15.152

• environmentally benign solvent water has been used [11]. Organocatalytic nanoreactors have emerged as an exciting area for novel organic syntheses, offering environmentally friendlier processes [13][14][15][16][17][18]. The distinct nanospace around the substrates, use of green solvents and catalyst recycling

Aqueous olefin metathesis: recent developments and applications

• Valerio Sabatino and
• Thomas R. Ward

Beilstein J. Org. Chem. 2019, 15, 445–468, doi:10.3762/bjoc.15.39

• substrates through the beads. However, the reaction rates are very low compared to the non-encapsulated catalyst G-II. The main advantage of the catalyst encapsulation is the catalyst recycling, as the alginate beads can be reused up to 10 times, retaining about 80% of activity. Catalysts bearing quaternary

• phosphine-based catalysts bearing quaternary ammonium tags 1 and 2. Synthesis of water-soluble catalysts 3 and 4 bearing quaternary ammonium tags. In situ formation of catalyst 5 bearing a quaternary ammonium group. Catalyst recycling of an ammonium-bearing catalyst. Removal of the water-soluble catalyst 12

Asymmetric synthesis of a high added value chiral amine using immobilized ω-transaminases

• Antonella Petri,
• Valeria Colonna and
• Oreste Piccolo

Beilstein J. Org. Chem. 2019, 15, 60–66, doi:10.3762/bjoc.15.6

• activities at higher temperatures without loss of efficiency and selectivity. Having in hand the good results obtained both in terms of activity and enantioselectivity, in particular with ATA-025-IMB at 50 °C, optimization of the reaction regarding the recycling of the enzyme was studied. Indeed, one of the

• insoluble in an aqueous medium. In batch recycling reactions, it was tested if the reused enzyme would be partially deactivated after several reaction cycles in the presence of the organic solvent. Therefore, the amount of enzyme was increased in order to reduce the reaction time and as a consequence to

• )-enantiomer. The good results obtained in the batch recycling reactions prompted us to investigate the possibility of a recycling process under flow conditions. For this purpose a microreactor was built consisting of a PEEK column which was filled with the enzyme. The reaction mixture was circulated within

Copolymerization of epoxides with cyclic anhydrides catalyzed by dinuclear cobalt complexes

• Yo Hiranoi and
• Koji Nakano

Beilstein J. Org. Chem. 2018, 14, 2779–2788, doi:10.3762/bjoc.14.255

• polystyrene samples. The recycling preparative HPLC was performed with YMC-GPC T-2000 and T-4000 columns (chloroform as an eluent). HPLC analysis for determining the ee was carried out using a DAICEL CHIRALCEL® IA-3 column (4.6 mm × 250 mm). Synthesis of mono(salen) (R,R)-7: A Schlenk tube was charged with (R

• water and extracted with CH2Cl2. The organic layer was washed with 1 M HCl and brine and concentrated under reduced pressure. The resulting crude product was purified by the recycling preparative HPLC to give 2-hydroxypropyl benzoate [43]. The ee of the benzoate was determined by HPLC analysis using a

Bioinspired cobalt cubanes with tunable redox potentials for photocatalytic water oxidation and CO₂ reduction

• Zhishan Luo,
• Yidong Hou,
• Jinshui Zhang,
• Sibo Wang and
• Xinchen Wang

Beilstein J. Org. Chem. 2018, 14, 2331–2339, doi:10.3762/bjoc.14.208

• oxidation and (b) CO2 reduction. (c) Long-time course of water oxidation for 1-CN under UV–vis light irradiation (λ > 300 nm) in two recycling tests. (d) CO2 reduction for 1-OMe under visible light irradiation (λ > 420 nm) in four recycling tests. aWithout 1-R. Long-time course of water oxidation for 1-CN

Heterogeneous acidic catalysts for the tetrahydropyranylation of alcohols and phenols in green ethereal solvents

• Ugo Azzena,
• Massimo Carraro,
• Gloria Modugno,
• Luisa Pisano and
• Luigi Urtis

Beilstein J. Org. Chem. 2018, 14, 1655–1659, doi:10.3762/bjoc.14.141

• recycling of the catalyst. Results and Discussion Taking 2-phenylethanol (1a) as a model compound, we investigated its conversion into the corresponding THP ether 3a by reacting 4 M solutions of this alcohol with a slight excess (1.1 equiv) of 3,4-dihydro-2H-pyran (2, DHP) in the presence of several acidic

Hypervalent organoiodine compounds: from reagents to valuable building blocks in synthesis

• Gwendal Grelier,
• Benjamin Darses and
• Philippe Dauban

Beilstein J. Org. Chem. 2018, 14, 1508–1528, doi:10.3762/bjoc.14.128

• this issue. A first solution has arisen from the development of polystyrene-supported reagents, which allows their recycling following simple filtration and re-oxidation (reaction 1 in Scheme 1a) [14][15]. More recently, the design of processes catalytic in iodine compounds has been extensively

• perborate enables the introduction of various aryl groups on the alkyne moiety. However, as a limitation of this study, the reaction allows for recycling at best 1 equivalent of the iodoarene while it involves the use of 1.4 equivalents of the λ3-iodane. Moreover, it requires the design of specific alkynyl

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

• [10][11]. The conversion of HMF to FDCA via homogeneous catalysis, however, suffers from two main drawbacks. Firstly, the yield in FDCA is relatively low due to poor oxidation selectivity. Secondly, the recycling of the catalysts and the purification of FDCA from the reaction mixtures is time

One hundred years of benzotropone chemistry

• Arif Dastan,
• Haydar Kilic and
• Nurullah Saracoglu

Beilstein J. Org. Chem. 2018, 14, 1120–1180, doi:10.3762/bjoc.14.98

• toward alcohols of 61+.BF4− in the auto-recycling process was also reported. However, to test the reactivity, the reactions of 61+.BF4− with a nucleophile such as NaBH4, diethylamine, and methanol were carried out to afford 7-adducts 64–66. Compound 64 was oxidized by DDQ to regenerate 61+.BF4− in good

Nanoreactors for green catalysis

• M. Teresa De Martino,
• Loai K. E. A. Abdelmohsen,
• Floris P. J. T. Rutjes and
• Jan C. M. van Hest

Beilstein J. Org. Chem. 2018, 14, 716–733, doi:10.3762/bjoc.14.61

• used and the usage of transition metals. Finding an approach to utilize chiral catalysts in water while minimizing their cost (i.e., recycling) is still a big challenge. In order to accomplish this, various strategies have been proposed and applied [17][18][19]. One significant, well-established and

• widely used strategy, is the use of site-isolated techniques, i.e., creating a separate micro environment [20][21][22] for catalysts to (1) allow their use in incompatible media, (2) to reduce their costs by recycling them, and (3) avoid any unfavorable environmental influences that might affect reaction

• calixarenes [38][39]. Besides these supramolecular cage structures compartmentalization can also be achieved in macromolecular nanoreactors. The advantage of employing these polymeric structures is their improved robustness and loading capacity, which makes recycling and efficient usage of catalytic species

Heterogeneous Pd catalysts as emulsifiers in Pickering emulsions for integrated multistep synthesis in flow chemistry

• Katharina Hiebler,
• Georg J. Lichtenegger,
• Manuel C. Maier,
• Eun Sung Park,
• Renie Gonzales-Groom,
• Bernard P. Binks and
• Heidrun Gruber-Woelfler

Beilstein J. Org. Chem. 2018, 14, 648–658, doi:10.3762/bjoc.14.52

• and lifetime. Apart from that, ligand-free Pd catalysts are also known in the literature [11][12]. However, homogeneous Pd catalysis often requires catalyst loadings in the order of mol % to achieve effective coupling and suffers from catalyst re-use and recycling problems [11][13]. Furthermore

Progress in copper-catalyzed trifluoromethylation

• Guan-bao Li,
• Chao Zhang,
• Chun Song and
• Yu-dao Ma

Beilstein J. Org. Chem. 2018, 14, 155–181, doi:10.3762/bjoc.14.11

• readily available TMSCF3 (Scheme 2). Similarly, the recycling of CuI was inefficient and led to the degradation of excessive trifluoromethyl anions. Differently, a novel strategy was developed to solve this problem, a Lewis acid such as trialkyl borate was added for the temporary trapping of the in situ

• all components in air, the environmentally friendly nature, and the recycling of the aqueous medium. Subsequently, the group of Li and Duan [58] reported an efficient method for the synthesis of α-trifluoromethyl ketones via addition of CF3 to aryl(heteroaryl)enol acetates using readily available