From dipivaloylketene to tetraoxaadamantanes

• Gert Kollenz and
• Curt Wentrup

Beilstein J. Org. Chem. 2018, 14, 1–10, doi:10.3762/bjoc.14.1

• of the bisdioxines becomes severely hindered in cyclic derivatives, so that the 38-membered ring compound 32 requires microwave heating at 170 °C to form tetraoxaadamantane 33, and the catenated compound 36 and calix[6]arene derivative 37 did not form tetraoxaadamantanes. The reaction mechanisms of

• -butylcalix[6]arene moiety in 37 (Figure 3), which is obtained from the bisdioxine diacid dichloride 12 and calixarene [42]. The wider upper rim is clearly seen in the X-ray structure and the compound demonstrates a pronounced ability to extract Cs+ ions from water into chloroform by forming endohedral

• 38-membered ring 32 requires forcing conditions to form a tetraoxaadamantane, and compounds 36 and 37 did not form tetraoxaadamantanes at all. Bistetraoxaadamantane derivatives. Cyclic bisdioxine derivative not forming a tetraoxaadamantane due to reduced cavity size. The bisdioxine-calix[6]arene

Quinone-catalyzed oxidative deformylation: synthesis of imines from amino alcohols

• Xinyun Liu,
• Johnny H. Phan,
• Benjamin J. Haugeberg,
• Shrikant S. Londhe and
• Michael D. Clift

Beilstein J. Org. Chem. 2017, 13, 2895–2901, doi:10.3762/bjoc.13.282

• scope of this methodology by employing a range of 1,2-amino alcohol substrates 1 (Table 2). As reported in Table 1, the reaction involving phenylglycinol gave the desired N-PMP imine (7a) in 85% yield (Table 2, entry 1). ortho-Substitution of the arene is reasonably well-tolerated, as 2

CF₃SO₂X (X = Na, Cl) as reagents for trifluoromethylation, trifluoromethylsulfenyl-, -sulfinyl- and -sulfonylation and chlorination. Part 2: Use of CF₃SO₂Cl

• Hélène Chachignon,
• Hélène Guyon and
• Dominique Cahard

Beilstein J. Org. Chem. 2017, 13, 2800–2818, doi:10.3762/bjoc.13.273

• visible light irradiation, a first SET reduction of CF3SO2Cl occurred, ultimately leading to the formation of the stabilised trifluoromethyl radical after releasing SO2 and chloride anion. This electron deficient radical was then added on the most electron-rich position of the arene substrate to yield

CF₃SO₂X (X = Na, Cl) as reagents for trifluoromethylation, trifluoromethylsulfenyl-, -sulfinyl- and -sulfonylation. Part 1: Use of CF₃SO₂Na

• Hélène Guyon,
• Hélène Chachignon and
• Dominique Cahard

Beilstein J. Org. Chem. 2017, 13, 2764–2799, doi:10.3762/bjoc.13.272

• . In the case of unsymmetrical biaryl substrates, mixtures of regioisomers at C4 and C5 were obtained (Scheme 48). In the reaction mechanism, PIFA played a dual role in the activation of the arene via a π-complex and in the generation of the CF3 radical from CF3SO2Na. More recently, Maruoka and co

Binding abilities of a chiral calix[4]resorcinarene: a polarimetric investigation on a complex case of study

• Marco Russo and
• Paolo Lo Meo

Beilstein J. Org. Chem. 2017, 13, 2698–2709, doi:10.3762/bjoc.13.268

• (with methyl groups in place of the n-propyl groups at the methylene bridges), an average pKa value as large as 6.3 ± 1 per arene subunit has been estimated from titration curves, under the hypothesis that the four subunits behave equivalently [32]. In the latter case, the deprotonation of phenol groups

• progressive deprotonation, and the consequent presence of an increasing negative charge, are reasonable. It is worth recalling here that the cone conformation of the resorcinarene scaffold is stabilized by the possible formation of a hydrogen-bond network between pairs of phenol groups on adjacent arene units

• , a carbonyl band of fair intensity appears at 1727 cm−1, similar to the one expected for an undissociated carboxylic group. In turn, extensive hydrogen bonding affects the flexibility of the macrocycle scaffold, as well as the possible double free rotation of the arene–CH2–proline single bond–single

Syntheses, structures, and stabilities of aliphatic and aromatic fluorous iodine(I) and iodine(III) compounds: the role of iodine Lewis basicity

• Tathagata Mukherjee,
• Soumik Biswas,
• Andreas Ehnbom,
• Subrata K. Ghosh,
• Ibrahim El-Zoghbi,
• Nattamai Bhuvanesh,
• Hassan S. Bazzi and
• John A. Gladysz

Beilstein J. Org. Chem. 2017, 13, 2486–2501, doi:10.3762/bjoc.13.246

• "spacers" that electronically insulate the arene ring from the perfluoroalkyl groups, have been previously isolated [17]. As described below, the pursuit of the preceding objectives has met with both success and some unanticipated speed bumps, for which parallel computational studies have provided valuable

• -tagged arene C6H5CH2CH2CH2Rf8 gives a 49.5:50.5 CF3C6F11/toluene partition coefficient. Values for doubly tagged analogs fall into the range (90.7–91.2):(9.3–8.8) (o, m, p-isomers), and that for the triply tagged species 1,3,5-C6H3(CH2CH2CH2Rf8)3 is >99.7:<0.3 [30]. As noted above, longer perfluoroalkyl

• with at least two Rfn substituents per arene ring. Given the ready isolation of the dinitro-substituted aryliodine(III) dichloride II-Me in Scheme 1 [31], this was seen as a surefire objective. However, this was not to be, so the results in this and the following section are presented in inverse

One-pot syntheses of blue-luminescent 4-aryl-1H-benzo[f]isoindole-1,3(2H)-diones by T3P^® activation of 3-arylpropiolic acids

• Melanie Denißen,
• Alexander Kraus,
• Guido J. Reiss and
• Thomas J. J. Müller

Beilstein J. Org. Chem. 2017, 13, 2340–2351, doi:10.3762/bjoc.13.231

• use of phenylpropiolic acid chloride and phenylpropiolic acid as starting materials [45], and as well oxidative arene–alkyne cyclization with dichloro-5,6-dicyano-benzoquinone (DDQ) [46]. Based upon our experience in using propylphosphonic acid anhydride (T3P®) [47] as a condensation agent for in situ

Phosphonic acid: preparation and applications

• Charlotte M. Sevrain,
• Mathieu Berchel,
• Hélène Couthon and
• Paul-Alain Jaffrès

Beilstein J. Org. Chem. 2017, 13, 2186–2213, doi:10.3762/bjoc.13.219

• dendrimers 67 [192]. The use of BrSiMe3 was also applied to diverse organometallic compounds as exemplified in Figure 20. This procedure was applicable to compounds featuring CpFe(CO)2 68 [193] or ferrocenyl 69 [194][195] moieties but also to palladium or platinium pincer complexes 70 [196] or arene–chrome

p-tert-Butylthiacalix[4]arenes functionalized by N-(4’-nitrophenyl)acetamide and N,N-diethylacetamide fragments: synthesis and binding of anionic guests

• Alena A. Vavilova and
• Ivan I. Stoikov

Beilstein J. Org. Chem. 2017, 13, 1940–1949, doi:10.3762/bjoc.13.188

• receptors for F−, CH3CO2− and H2PO4− ions, which based on the synthesized thiacalix[4]arenes, have been obtained. It was shown that p-tert-butylthiacalix[4]arene tetrasubstituted at the lower rim by N-(4’-nitrophenyl)acetamide moieties bonded to the anions studied with association constants within the range

• receptor. In contrast to the 1,3-disubstituted macrocycle containing two N-(4’-nitrophenyl)acetamide moieties, the 1,2-disubstituted thiacalix[4]arene, which contains only one such fragment and a N,N-diethylacetamide moiety, selectively binds F− anions. Keywords: anion binding; synthesis; thiacalixarenes

• type of anion is needed. (Thia)calix[4]arene derivatives are a favorable platform for the design of such structures [24][25][26][27][28][29][30][31][32][33][34]. Due to their macrocyclic nature and the possibility to modify them in three different ways (upper and lower rims and bridge fragments), they

Synthesis of benzannelated sultams by intramolecular Pd-catalyzed arylation of tertiary sulfonamides

• Valentin A. Rassadin,
• Mirko Scholz,
• Anastasiia A. Klochkova,
• Armin de Meijere and
• Victor V. Sokolov

Beilstein J. Org. Chem. 2017, 13, 1932–1939, doi:10.3762/bjoc.13.187

• , the tertiary analogue 5 underwent cyclization smoothly and rapidly (1 h) under the same conditions to furnish the benzannelated sultam 6 in 78% yield (Scheme 2). Thus, in order to enable the preparation of arene-annelated tertiary sultams of type 6 along this route, an effective and versatile access

• approach to arene-annelated sultams. Pd-catalyzed cyclization of (2-iodophenyl)sulfonamides 3 and 5. Preparation of 4-methoxybenzyl-protected methyl 2-(N-o-iodoarylsulfamoyl)acetates 8. Reagents and conditions A: MeO2CCH2SO2Cl (2a), Py, MeCN, 60 °C, 48 h; conditions B: MeO2CCH2SO2Cl (2a), PhNEt2, CH2Cl2

• , rt, 20 h; conditions C: EtO2CCH(Me)SO2Cl (2b), Py, MeCN, 60 °C, 48 h. Synthesis of arene-annelated sultams 10 by Pd-catalyzed intramolecular arylation of a C–H acidic methylene group. Palladium-catalyzed transformation of N-(2-iodophenyl)-N-(4-methoxybenzyl-benzylsulfonamide 12. Ar = 4-MeOC6H4; a

Mechanochemical synthesis of small organic molecules

• Tapas Kumar Achar,
• Anima Bose and
• Prasenjit Mal

Beilstein J. Org. Chem. 2017, 13, 1907–1931, doi:10.3762/bjoc.13.186

• ], carbon–heteroatom [41][42], metal–ligand coordination bonds [43], non-covalent interactions such as hydrogen bonds or π–π arene stacking interactions [44], etc. are popularly known in literature. In this review the efforts are given towards documentation of various mechanochemical reactions like organic

• palladium-catalyzed site selective mechanochemical dehydrogenative C–H/C–H arylation between oxime and arene moiety for the construction of Csp2–Csp2 bond with high para-selectivity of arene component via LAG. Using 10 mol % of Pd(OAc)2, 2.0 equiv of Na2S2O8 and 1.0 equiv TfOH the biaryls were synthesized

• using dioxazolone as the amide source under ball milling conditions (Scheme 54). Using 5 mol % of Rh catalyst, 20 mol % of AgSbF6 and 20 mol % of AgOAc they have successfully achieved up to 99% of ortho-amidation product with diversely substituted arene moiety [186]. Recently Bolm and co-workers

Iodoarene-catalyzed cyclizations of N-propargylamides and β-amidoketones: synthesis of 2-oxazolines

• Somaia Kamouka and
• Wesley J. Moran

Beilstein J. Org. Chem. 2017, 13, 1823–1827, doi:10.3762/bjoc.13.177

• studied with various arylamide and alkyne substituents. All functional groups were well tolerated apart from an alkyne terminated with an alkyl substituted arene which led to a diminished yield of product, i.e., 6g. The mechanism of this cyclization is proposed to proceed though activation of the alkyne

An effective Pd nanocatalyst in aqueous media: stilbene synthesis by Mizoroki–Heck coupling reaction under microwave irradiation

• Carolina S. García,
• Paula M. Uberman and
• Sandra E. Martín

Beilstein J. Org. Chem. 2017, 13, 1717–1727, doi:10.3762/bjoc.13.166

• yields. When an ortho-substituted arene, 1g, was used, product 9 was obtained in only moderate yield compared with para-substituted stilbene 8 synthesized under the same conditions (entries 6 and 7, Table 2). This behavior can be explained by the steric hindrance caused by the methylene group in ortho

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

• quinazolinones. A putative mechanism involved the homolysis of DTBP to generate tert-butoxide radicals, which in turn abstracts a proton radical from the methyl(hetero)arene to facilitate the formation of a benzylic radical. The benzylic radical couples with o-aminobenzylamide to generate H. It then interacts

Sustainable synthesis of 3-substituted phthalides via a catalytic one-pot cascade strategy from 2-formylbenzoic acid with β-keto acids in glycerol

• Lina Jia and
• Fuzhong Han

Beilstein J. Org. Chem. 2017, 13, 1425–1429, doi:10.3762/bjoc.13.139

• limitations of this one-pot cascade aldol/cyclization system. Typical results are shown in Scheme 2. The annulation proceeded smoothly with β-keto acids 2 bearing diverse arene substituents to provide the corresponding isobenzofuran-1(3H)-ones in moderate to excellent yields. For para-substituted β-keto acids

Regioselective (thio)carbamoylation of 2,7-di-tert-butylpyrene at the 1-position with iso(thio)cyanates

• Anna Wrona-Piotrowicz,
• Marzena Witalewska,
• Janusz Zakrzewski and
• Anna Makal

Beilstein J. Org. Chem. 2017, 13, 1032–1038, doi:10.3762/bjoc.13.102

• .) [1][2][3][4][5][6][7]. Since 1 is an electron-rich arene, aromatic electrophilic substitution seems to be the simplest method for this purpose, and a plethora of substituted pyrenes have been synthesized in this way [1]. As is shown in Figure 1, the most reactive in such reactions are positions 1, 3

• with the arene ring of the protonated aromatic iso(thio)cyanate during formation of the Wheland complex, which may direct the electrophilic attack partly to the 4-position of the pyrene moiety. To the best of our knowledge, the reaction reported here is the first example of a C1-selective substitution

Transition-metal-catalyzed synthesis of phenols and aryl thiols

• Yajun Liu,
• Shasha Liu and
• Yan Xiao

Beilstein J. Org. Chem. 2017, 13, 589–611, doi:10.3762/bjoc.13.58

• reoxidation of Pd(0) as the reaction couldn't proceed with a stoichiometric amount of Pd(OAc)2 under argon. In 2012, the Rao group and the Dong group simultaneously reported a palladium catalyzed ortho-hydroxylation of aryl ketones, and thus further broadened the directing groups of arene substrates [70][71

Correction: Inherently chiral calix[4]arenes via oxazoline directed ortholithiation: synthesis and probe of chiral space

• Simon A. Herbert,
• Laura J. van Laeren,
• Dominic C. Castell and
• Gareth E. Arnott

Beilstein J. Org. Chem. 2017, 13, 347–347, doi:10.3762/bjoc.13.38

• Simon A. Herbert Laura J. van Laeren Dominic C. Castell Gareth E. Arnott Department of Chemistry and Polymer Science, Stellenbosch University, Private Bag X1, Matieland 7602, South Africa 10.3762/bjoc.13.38 Keywords: calix[4]arene; inherently chiral; ortholithiation; oxazoline; Tsuji–Trost; In

New approaches to organocatalysis based on C–H and C–X bonding for electrophilic substrate activation

• Pavel Nagorny and
• Zhankui Sun

Beilstein J. Org. Chem. 2016, 12, 2834–2848, doi:10.3762/bjoc.12.283

• of an electron-withdrawing group into the aryl ring (i.e., NO2, CN, CF3, etc.) could significantly enhance this binding and result in stronger hydrogen bonds between the arene and the anion. Thus, the gas-phase binding energy of the nitrobenzene and chloride anion complex containing two C–H hydrogen

• L15 were proposed to form additional C–H hydrogen bonds between arene or α-halogenated acetyl groups and the carbonyl of lactide. X-ray crystallographic analysis and molecular modeling provided the evidence of such interactions in solid state, and the titration studies established weak binding (Ka ≈ 1

cis-Diastereoselective synthesis of chroman-fused tetralins as B-ring-modified analogues of brazilin

• Dimpee Gogoi,
• Runjun Devi,
• Pallab Pahari,
• Bipul Sarma and
• Sajal Kumar Das

Beilstein J. Org. Chem. 2016, 12, 2816–2822, doi:10.3762/bjoc.12.280

• Abstract We have synthesized a series of cis-6a,7,8,12b-tetrahydro-6H-naphtho[2,1-c]chromen-6a-ols as B-ring-modified analogues of (±)-brazilin. A completely regio- and cis-diastereoselective intramolecular Friedel–Crafts epoxy–arene cyclization of 1-tetralone-derived glycidyl ethers catalyzed by Brønsted

• been reductively removed by a diastereoselective method which should be useful in future for preparing libraries of chroman-fused tetralins with trans-stereochemistry at the ring junction. Keywords: brazilin; chroman; epoxy-arene cyclization; natural-product-like molecules; tetralin; Findings The

• studied during the past 15 years [19]. Moreover, on many occasions natural product-like molecules exhibit more potent biological activities than the parent natural products [20]. Meanwhile, the intramolecular Friedel–Crafts epoxy–arene (IFCEA) cyclization has been well-established as a powerful tool for

Palladium-catalyzed ring-opening reactions of cyclopropanated 7-oxabenzonorbornadiene with alcohols

• Katrina Tait,
• Oday Alrifai,
• Rebecca Boutin,
• Jamie Haner and
• William Tam

Beilstein J. Org. Chem. 2016, 12, 2189–2196, doi:10.3762/bjoc.12.209

• ). Syn-stereoisomeric products 2 and 3 can be obtained using rhodium [14], palladium [15], or nickel [16] catalysts with an arene nucleophile and when palladium [17] or nickel [18] are used with an alkyl nucleophile. Recently, it was shown that the syn-stereoisomeric product 4 could be obtained through

• both bridgehead positions was first investigated. With a methyl group at both bridge head positions, the yield was decreased to 40% at 90 °C (Table 3, entry 1). Substitution on the arene portion of cyclopropanated oxabenzonorbornadiene 8a was investigated. p-Methoxy-substituted 8c underwent minimal

• halide substitution on the arene was also investigated in the ortho position which decreased the yield to 37% (Table 3, entry 4). The scope of the reaction was then extended to include examples of unsymmetrical functionalized substrates 8f–j bearing substituents at the C1 position. With a substituent at

Superelectrophilic activation of 5-hydroxymethylfurfural and 2,5-diformylfuran: organic synthesis based on biomass-derived products

• Dmitry S. Ryabukhin,
• Dmitry N. Zakusilo,
• Mikhail O. Kompanets,
• Anton A.Tarakanov,
• Irina A. Boyarskaya,
• Tatiana O. Artamonova,
• Mikhail A. Khohodorkovskiy,
• Iosyp O. Opeida and
• Aleksander V. Vasilyev

Beilstein J. Org. Chem. 2016, 12, 2125–2135, doi:10.3762/bjoc.12.202

• temperature for 1–24 h gives rise to 5-arylmethylfurfurals (yields of 17–91%) and 2-arylmethyl-5-(diarylmethyl)furans (yields of 10–37%). The formation of these two types of reaction products depends on the nucleophilicity of the arene. The same reactions under the action of acidic zeolites H-USY in high

• the substrate (arene) molecules. We also varied reaction conditions (time, amount of arene) in TfOH to check yields of compounds 3 and 4. In general, increasing the reaction time up to 3–24 h led to an increase in the yield of furans 4 and a decreased yield of compounds 3 (compare pairs of entries in

• , 11, 13, and 15). The coordination of aluminum halides with the aldehyde group results in the activation of one of the aldehyde groups, catalyzing the reaction subsequently with two arene molecules resulting in the 1,1-diarylated product. The second aldehyde group does not take part in the reaction

Practical synthetic strategies towards lipophilic 6-iodotetrahydroquinolines and -dihydroquinolines

• David R. Chisholm,
• Garr-Layy Zhou,
• Ehmke Pohl,
• Roy Valentine and
• Andrew Whiting

Beilstein J. Org. Chem. 2016, 12, 1851–1862, doi:10.3762/bjoc.12.174

• literature [13]. An initial investigation with the corresponding bromides indicated that these were unreactive towards many cross-coupling methodologies, presumably due to the highly electron-rich arene [14]. Reactions such as the Sonogashira coupling, for example, often required high catalyst loadings

Amidofluorene-appended lower rim 1,3-diconjugate of calix[4]arene: synthesis, characterization and highly selective sensor for Cu²⁺

• Rahman Hosseinzadeh,
• Mohammad Nemati,
• Reza Zadmard and
• Maryam Mohadjerani

Beilstein J. Org. Chem. 2016, 12, 1749–1757, doi:10.3762/bjoc.12.163

• Basic Science, University of Mazandaran, Babolsar, Iran 10.3762/bjoc.12.163 Abstract Functionalization of calix[4]arene with amidofluorene moieties at the lower rim led to formation of the 1,3-diconjugate of calix[4]arene L as a novel fluorescent chemosensor for Cu2+. The receptor molecule L exhibited

• of 9.6 × 10−8 M. Keywords: calix[4]arene; chemosensor; copper ions; fluorene; fluorescence; Introduction Owing to the substantial role of fluorescent chemosensors in biological, environmental, and chemical processes, their design and synthesis, especially for detection of metal ions has attracted

• supramolecular structures, especially calixarene derivatives, has been an appealing field for research [14]. Calixarene has been considered as an effective molecular scaffold in the improvement of fluorescent and chromogenic sensors, especially for metal-ion recognition [14][15]. Calix[4]arene derivatives having

Rearrangements of organic peroxides and related processes

• Ivan A. Yaremenko,
• Vera A. Vil’,
• Dmitry V. Demchuk and
• Alexander O. Terent’ev

Beilstein J. Org. Chem. 2016, 12, 1647–1748, doi:10.3762/bjoc.12.162