Cobalt-catalyzed directed C–H alkenylation of pivalophenone N–H imine with alkenyl phosphates

• Wengang Xu and
• Naohiko Yoshikai

Beilstein J. Org. Chem. 2018, 14, 709–715, doi:10.3762/bjoc.14.60

• cycle illustrated in Scheme 5. An alkylcobalt species A, generated from the cobalt precatalyst and the Grignard reagent, would undergo cyclometalation of magnesium alkylidene amide 1·MgX, generated from imine 1 and the Grignard reagent, to give a cobaltacycle species B while liberating an alkane R–H

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

• magnesium sulphate and analysed on a CP-wax 52 CB GC column (50 m × 0.53 m × 2 µm) (GC method: 60 °C for 3 min; 30 °C/min to 105 °C; 105 °C for 7 min; 30 °C/min to 250 °C; 250 °C for 1 minute). Dodecane (5 mM) was added as standard. Work-up semi-preparative scale The reaction mixture was directly collected

Enzyme-free genetic copying of DNA and RNA sequences

• Marilyne Sosson and
• Clemens Richert

Beilstein J. Org. Chem. 2018, 14, 603–617, doi:10.3762/bjoc.14.47

• aqueous media, hydrolysis of activated nucleotides is all but unavoidable, and hydrolytic deactivation becomes more likely when significant concentrations of magnesium ions are present [31]. High initial concentrations of monomers are usually used to compensate for this problem (0.1 M solutions are not

• dimethylaminopyridine [61]. With aminoterminal primers, in situ activation and organocatalysis with 1-methylimidazole in a magnesium-free buffer had led to encouraging results, even at submillimolar nucleotide concentration [62]. So, starting from a primer extension reaction with an RNA-system that gave less than 1

Gram-scale preparation of negative-type liquid crystals with a CF₂CF₂-carbocycle unit via an improved short-step synthetic protocol

• Tatsuya Kumon,
• Shohei Hashishita,
• Takumi Kida,
• Shigeyuki Yamada,
• Takashi Ishihara and
• Tsutomu Konno

Beilstein J. Org. Chem. 2018, 14, 148–154, doi:10.3762/bjoc.14.10

• leads to the formation of the corresponding magnesium acetal Int-D, (ii) the alkoxide attacks another ester carbonyl moiety in the molecule to form the corresponding 5-membered ring acetal intermediate (Int-E) [15][16][17], after which immediate hydrolysis leads to the exclusive formation of the

• chloride with the γ-keto ester 6 furnishes the corresponding magnesium alkoxide Int-F, which can be easily converted to the 5-membered ring intermediate, Int-G, as already discussed in the reaction of 7→6 (Figure 2b). However, the reaction at a higher temperature may lead to the elimination of MeOMgCl

• addition reaction, a Michael addition reaction, giving rise to the corresponding magnesium enolate Int-L. The subsequent hydrolysis of Int-L then leads to the γ-hydroxyketone 8a', which easily tautomerizes into the more stable 5-membered hemiacetal 8a. From the above insight into the reaction mechanism, if

Reactivity of bromoselenophenes in palladium-catalyzed direct arylations

• Aymen Skhiri,
• Ridha Ben Salem,
• Jean-François Soulé and
• Henri Doucet

Beilstein J. Org. Chem. 2017, 13, 2862–2868, doi:10.3762/bjoc.13.278

• to room temperature and stirred during 20 h. After addition of water, the extraction was carried out with diethyl ether. Then, the organic phase was dried over magnesium sulphate. Finally, evaporation of the solvent and purification on silica gel afforded the 5-bromo-2-arylselenophenes 15–17. Eluents

Preparation and isolation of isobenzofuran

• Morten K. Peters and
• Rainer Herges

Beilstein J. Org. Chem. 2017, 13, 2659–2662, doi:10.3762/bjoc.13.263

• hydrogen carbonate solution and filtered over Celite. The aqueous phase was extracted three times with dichloromethane. The combined organic layers were dried over magnesium sulfate and the solvent was removed under reduced pressure. The crude product was purified by column chromatography on silica gel

• and then twice with water. The combined organic layers were dried over magnesium sulfate and the solvent was removed under reduced pressure. The crude product was purified by column chromatography on silica gel (cyclohexane/ethyl acetate 8:2, Rf 0.92). The solvent was carefully evaporated at 20 °C. A

Exploring mechanochemistry to turn organic bio-relevant molecules into metal-organic frameworks: a short review

• Vânia André,
• Sílvia Quaresma,
• João Luís Ferreira da Silva and
• M. Teresa Duarte

Beilstein J. Org. Chem. 2017, 13, 2416–2427, doi:10.3762/bjoc.13.239

• biomedical applications [128]. Having in mind the synthesis of BioMOFs involving the excipient magnesium oxide initially proposed by Byrn et al. [129], Chow et al. and Friščić et al. developed new BioMOFs by LAG, grinding together MgO with the non-steroidal anti-inflammatory drugs (NSAIDS) ibuprofen (S and

• RS-forms), salicylic acid [130] and naproxen using water as the grinding liquid [7]. With naproxen, LAG was also used to screen for hydrated forms of magnesium–naproxen by systematically varying the fraction of water in the LAG experiments [7]. Low, intermediate and high amounts of water as grinding

• ) fragment of the crystal structure of a mechanochemically obtained magnesium–ibuprofen complex; d) fragment of the crystal structure of a mechanochemically obtained magnesium–salicylate complex; e) screening for different hydrated forms of magnesium–naproxen BioMOFs by systematically varying the quantity of

Solvent-free and room temperature synthesis of 3-arylquinolines from different anilines and styrene oxide in the presence of Al₂O₃/MeSO₃H

• Hashem Sharghi,
• Mahdi Aberi,
• Mohsen Khataminejad and
• Pezhman Shiri

Beilstein J. Org. Chem. 2017, 13, 1977–1981, doi:10.3762/bjoc.13.193

• solution was dried over magnesium sulfate; the solvent was evaporated to give the crude product, which was purified by silica gel column chromatography employing n-hexane/ethyl acetate (10:1) as eluent. Investigation of the reusability of Al2O3. Synthesis of 3-arylquinolines from anilines and styrene oxide

Oxidative dehydrogenation of C–C and C–N bonds: A convenient approach to access diverse (dihydro)heteroaromatic compounds

• Santanu Hati,
• Ulrike Holzgrabe and
• Subhabrata Sen

Beilstein J. Org. Chem. 2017, 13, 1670–1692, doi:10.3762/bjoc.13.162

• -tetrahydroquinazolines which underwent oxidative dehydrogenation in the presence of magnesium iodide (that generates iodine) to afford the aromatic quinazoline 80 in excellent yield. Zhou et al. [90] reported a similar example in the presence of catalytic ferrous chloride and molecular oxygen for the synthesis of

• . Magnesium iodide-catalyzed synthesis of quinazolines. Ferrous chloride-catalyzed aerobic dehydrogenation of 1,2,3,4-tetrahydroquinolines. Cu(I)-catalyzed oxidative aromatization of indoles. Putative mechanism of the transformation. Oxidative dehydrogenation of pyrimidinones and pyrimidines. Putative

Chemical systems, chemical contiguity and the emergence of life

• Terrence P. Kee and
• Pierre-Alain Monnard

Beilstein J. Org. Chem. 2017, 13, 1551–1563, doi:10.3762/bjoc.13.155

• protocellular „metabolism“. Inspired by the non-enzymatic, template-directed RNA polymerization in bulk aqueous solutions [7] (the synthesis of a RNA using a primer/template system and magnesium ions as catalysts), the Szostak group [21][82] has demonstrated that RNA could be synthesized within mixed vesicles

• , Chen et al. [87] established that an inorganic catalyst itself, magnesium ions, could be delivered to non-functional hammerhead ribozymes with consequent induction of activity (self-cleavage). The enzymatic reactions were conducted within vesicles formed by long chained fatty acids, such as

Effect of uridine protecting groups on the diastereoselectivity of uridine-derived aldehyde 5’-alkynylation

• Raja Ben Othman,
• Mickaël J. Fer,
• Laurent Le Corre,
• Sandrine Calvet-Vitale and
• Christine Gravier-Pelletier

Beilstein J. Org. Chem. 2017, 13, 1533–1541, doi:10.3762/bjoc.13.153

• triisopropylsilyl group. The addition of triethylsilylacetylide magnesium bromide gave a 5’R /5’S ratio of 5:95 (Table 2, entries 9 and 10). To determine if R3 was able to influence this ratio, we also tested trimethylsilylacetylmagnesium bromide (Table 2, entry 11) and triisopropylsilylacetylmagnesium bromide

Synthesis of ribavirin 2’-Me-C-nucleoside analogues

• Fanny Cosson,
• Aline Faroux,
• Jean-Pierre Baltaze,
• Jonathan Farjon,
• Régis Guillot,
• Jacques Uziel and
• Nadège Lubin-Germain

Beilstein J. Org. Chem. 2017, 13, 755–761, doi:10.3762/bjoc.13.74

• mixture by α- and β-attack; this second one can be explained by a magnesium complexation with the base. More interestingly, the methylation proceeded stereoselectively leading to 13b in 87% yield when trimethylaluminium was used [24]. The stereochemical outcome of this reaction was determined by selective

Sulfamide chemistry applied to the functionalization of self-assembled monolayers on gold surfaces

• Loïc Pantaine,
• Vincent Humblot,
• Vincent Coeffard and
• Anne Vallée

Beilstein J. Org. Chem. 2017, 13, 648–658, doi:10.3762/bjoc.13.64

• phase was extracted with dichloromethane. The organic phases were combined, dried on anhydrous magnesium sulfate, filtered and concentrated under reduced pressure. The crude product was then purified by preparative chromatography on silica gel (pentane/EtOAc, 1/1) to afford the desired sulfamide 1 as a

Adsorption of RNA on mineral surfaces and mineral precipitates

• Elisa Biondi,
• Yoshihiro Furukawa,
• Jun Kawai and
• Steven A. Benner

Beilstein J. Org. Chem. 2017, 13, 393–404, doi:10.3762/bjoc.13.42

• cationic components (for example, magnesium carbonate, calcium carbonate, strontium carbonate, and barium carbonate). Here, we may even seek a Periodic Table trend, where adsorption changes consistently in a series of minerals as one of their elements is replaced by another element in a row or column of

• . These are interesting not only because carbon dioxide is likely to have been an abundant component of an early Earth atmosphere, but also because alkaline earths form a well-known set of binary carbonates that include insoluble magnesium, calcium, strontium, and barium carbonates (magnesite, calcite

• calculated by subtraction of counts per minute in the washes. The results are shown in Figure 1. Here, we were surprised to see a Periodic Table trend in these carbonates. Thus, while only a quarter of the radioactivity remained bound to the surface of the specimen of magnesite (with magnesium), ≈94% of the

NMR reaction monitoring in flow synthesis

• M. Victoria Gomez and
• Antonio de la Hoz

Beilstein J. Org. Chem. 2017, 13, 285–300, doi:10.3762/bjoc.13.31

• catalyst concentration was found. An interesting point to consider is the comparison of in-line and off-line analysis. For example, Duchateau et al. [41] described the preparation of Grignard reagents from aryl halides and magnesium using a fluidized bed reactor under continuous-flow conditions. In a

The reductive decyanation reaction: an overview and recent developments

• Jean-Marc R. Mattalia

Beilstein J. Org. Chem. 2017, 13, 267–284, doi:10.3762/bjoc.13.30

• method A (61) but aliphatic nitriles are not converted to the desired product with method B. Trapping of radicals with method A led the authors to propose the electron transfer mechanism described in Scheme 21. The complex 62 reacts with the Grignard reagent to form the nickel-magnesium hydride

Continuous-flow synthesis of highly functionalized imidazo-oxadiazoles facilitated by microfluidic extraction

• Ananda Herath and
• Nicholas D. P. Cosford

Beilstein J. Org. Chem. 2017, 13, 239–246, doi:10.3762/bjoc.13.26

• was carried out with a back pressure of 4.0 bar. The reaction mixture was mixed with excess water and extracted three times with dichloromethane. The combined organic layers were washed with brine, dried over magnesium sulfate, filtered, and concentrated and the residue was purified via automated

• back pressure regulator. This reaction was carried out with a back pressure of 4.0 bar. The reaction mixture was mixed with excess water and extracted three times with dichloromethane. The combined organic layers were washed with brine, dried over magnesium sulfate, filtered, and concentrated and the

Selective synthesis of thioethers in the presence of a transition-metal-free solid Lewis acid

• Federica Santoro,
• Matteo Mariani,
• Federica Zaccheria,
• Rinaldo Psaro and
• Nicoletta Ravasio

Beilstein J. Org. Chem. 2016, 12, 2627–2635, doi:10.3762/bjoc.12.259

• to the displacement of propargyl alcohols with thiols [18]. Heterogeneous systems are very rare. Corma and Sabater used a heterogeneous system based on palladium on magnesium oxide under borrowing hydrogen conditions [19]. The reaction has to be carried out at 180 °C under N2 in trifluorotoluene with

Synthesis and characterization of fluorinated azadipyrromethene complexes as acceptors for organic photovoltaics

• Forrest S. Etheridge,
• Roshan J. Fernando,
• Sandra Pejić,
• Matthias Zeller and
• Geneviève Sauvé

Beilstein J. Org. Chem. 2016, 12, 1925–1938, doi:10.3762/bjoc.12.182

• ) and diethylamine (3.23 g, 44.2 mmol) were added and refluxed for 24 h. The mixture was cooled to room temperature and then chilled in an ice bath before adding a 1 M HCl solution dropwise (100 mL). The mixture was then extracted 3× with dichloromethane, dried with anhydrous magnesium sulfate, filtered

• magnesium sulfate, filtered and rotary evaporated to obtain a yellow oil. This oil was then dissolved in 1-butanol (200 mL) in a 500 mL round-bottom flask. Ammonium acetate (37.6 g) was added to the solution and stirred and heated to reflux. After continued refluxing for 24 h, the 1-butanol was removed by

Beta-hydroxyphosphonate ribonucleoside analogues derived from 4-substituted-1,2,3-triazoles as IMP/GMP mimics: synthesis and biological evaluation

• Tai Nguyen Van,
• Audrey Hospital,
• Corinne Lionne,
• Lars P. Jordheim,
• Charles Dumontet,
• Christian Périgaud,
• Laurent Chaloin and
• Suzanne Peyrottes

Beilstein J. Org. Chem. 2016, 12, 1476–1486, doi:10.3762/bjoc.12.144

• hydrophilic pocket (Ser251 and Lys215) where the hydroxy groups of the sugar interact and a phosphonate binding site close to the magnesium ion located in the substrate binding site. Thus, as few cytosine-containing analogues were equipotent in terms of cN-II inhibition to their purine counterparts (Figure 1

• very close to that of IMP or to the previously characterized inhibitor, UA1776. This may be explained by the presence of a phosphonate chain in all compounds which binds to the protein by electrostatic interactions through the magnesium ion and thus largely contributing to the final score. As the

• shown in Figure 6, the presence of amide function in position 4 of the triazole ring seems favourable for the inhibitory activity whereas a carboxylic or ester group is less advantageous. As expected, strong ionic interactions between the magnesium ion and the phosphonate oxygen were observed. In

Multicomponent reactions: A simple and efficient route to heterocyclic phosphonates

• Mohammad Haji

Beilstein J. Org. Chem. 2016, 12, 1269–1301, doi:10.3762/bjoc.12.121

• and the structure of the dialkyl phosphite and isatin (Scheme 9) [35]. In this way a one-pot three-component reaction between 1-tosylpiperidine-4-one (34), aromatic amines 35 and diethyl phosphonate in the presence of magnesium perchlorate as a catalyst, under neat conditions at 80 °C afforded α

Stereoselective synthesis of tricyclic compounds by intramolecular palladium-catalyzed addition of aryl iodides to carbonyl groups

• Jakub Saadi,
• Christoph Bentz,
• Kai Redies,
• Dieter Lentz,
• Reinhold Zimmer and
• Hans-Ulrich Reissig

Beilstein J. Org. Chem. 2016, 12, 1236–1242, doi:10.3762/bjoc.12.118

• of organometallics such as lithium, magnesium or zinc organic compounds to carbonyl groups leading to alcohols is an important standard operation in organic synthesis providing high stereoselectivities in many cases. The in situ generation of the nucleophilic species from the corresponding organic

• halides in the presence of the carbonyl compound is also known, e.g., the Barbier reaction employing magnesium. The related transformation described in this report very likely involves an arylpalladium species as nucleophile that is in situ generated from the aryl iodide moiety. Similar palladium

Catalytic asymmetric synthesis of biologically important 3-hydroxyoxindoles: an update

• Bin Yu,
• Hui Xing,
• De-Quan Yu and
• Hong-Min Liu

Beilstein J. Org. Chem. 2016, 12, 1000–1039, doi:10.3762/bjoc.12.98

• yields (up to 99% yield, Scheme 42) [59]. Interestingly, treatment of the adducts with magnesium monoperoxyphthalate (MMPP) gave the corresponding azoxy compounds in excellent yields (up to 99%) and with complete regioselectivities and excellent enantioselectivities (up to 99% ee). A stereochemical model

1H-Imidazol-4(5H)-ones and thiazol-4(5H)-ones as emerging pronucleophiles in asymmetric catalysis

• Antonia Mielgo and
• Claudio Palomo

Beilstein J. Org. Chem. 2016, 12, 918–936, doi:10.3762/bjoc.12.90

• . The authors found that whilst the best results for allylation of oxazol-4-(5H)-ones were achieved from zinc enolates, thiazol-4-(5H)-ones produced the best outcome when the magnesium enolate was used. After optimization it was shown that the reaction was efficient with different cinnamyl tert-butyl

Study on the synthesis of the cyclopenta[f]indole core of raputindole A

• Nils Marsch,
• Mario Kock and
• Thomas Lindel

Beilstein J. Org. Chem. 2016, 12, 334–342, doi:10.3762/bjoc.12.36

• , which was synthesized via Heck reaction with but-3-en-2-ol (5, 89%) in the presence of LiCl, inspired by a procedure by Camp and coworkers [36]. Propargyl bisindole 7 was obtained after conversion of 4 (2 equiv) to the magnesium acetylide (iPrMgCl in THF) and Grignard reaction with ketone 6. Due to the

• synthesized by hydroxyalkylation with β-cyclocitral [46]. Hydroxyalkylation of Boc-protected 6-iodoindole (3) with 6-β-cyclocitral (30) was possible after iodine/magnesium exchange, affording adduct 31 (Scheme 5). However, treatment of 31 with SnCl4 in DCM did not afford any defined product. This changed