Recent applications of chiral calixarenes in asymmetric catalysis

• Mustafa Durmaz,
• Erkan Halay and
• Selahattin Bozkurt

Beilstein J. Org. Chem. 2018, 14, 1389–1412, doi:10.3762/bjoc.14.117

• ) reduction In 2011, Katz et al. developed two optically pure aluminum complexes of inherently chiral calix[4]arene 111 and 112 bearing also an asymmetric carbon center on the phenylethylamine substituent (Scheme 33) as catalysts for asymmetric Meerwein–Ponndorf–Verley (MPV) reduction of acetophenone

Cross-coupling of dissimilar ketone enolates via enolonium species to afford non-symmetrical 1,4-diketones

• Keshaba N. Parida,
• Gulab K. Pathe,
• Shimon Maksymenko and
• Alex M. Szpilman

Beilstein J. Org. Chem. 2018, 14, 992–997, doi:10.3762/bjoc.14.84

• -coupling of 4 (R1 = Ph, R2 = H) with the TMS enol ether 5 (R3 = p-MeOC6H4, R4 = H) afforded compound 8 in 72% yield with no oxidation of the electron-rich aromatic ring observed. The only side product being tosyloxy-acetophenone. The same enolonium species 4 (R1 = Ph, R2 = H) reacts with the TMS enol ether

• 5 (R3 = p-O2NC6H4, R4 = H) to form 9 in 65% yield. The method is by no means restricted to enolonium species of acetophenone as may be observed from the formation of the whole series of para-halogenated 1,4-diketones. Thus, the p-fluoro-, p-chloro-, and p-bromo-substituted enolonium species 4 (R3

Volatiles from the xylarialean fungus Hypoxylon invadens

• Jeroen S. Dickschat,
• Tao Wang and
• Marc Stadler

Beilstein J. Org. Chem. 2018, 14, 734–746, doi:10.3762/bjoc.14.62

• 2-phenylethanol (10), and the trace components acetophenone (9), terpinen-4-ol (13), and indole (16). For several other compounds in the headspace extract close hits for highly substituted aromatic compounds were found in our mass spectral libraries, but the mass spectra and retention indices for

An alternative to hydrogenation processes. Electrocatalytic hydrogenation of benzophenone

• Cristina Mozo Mulero,
• Alfonso Sáez,
• Jesús Iniesta and
• Vicente Montiel

Beilstein J. Org. Chem. 2018, 14, 537–546, doi:10.3762/bjoc.14.40

• ohmic drop at the whole process. In the case of organic electrosynthesis, electrocatalytic hydrogenation of aromatic ketones, specifically acetophenone, has been recently carried out [22][23] achieving a high selectivity using the above-mentioned technology. In this work, we have chosen benzophenone, as

Conformational preferences of α-fluoroketones may influence their reactivity

• Graham Pattison

Beilstein J. Org. Chem. 2017, 13, 2915–2921, doi:10.3762/bjoc.13.284

• -fluorinated ketones was not the expected outcome through simple arguments of electronegativity differences. Comparison of the reactivity of each α-haloacetophenone to non-halogenated acetophenone showed the halogenated derivatives to be significantly more reactive (no reduction of acetophenone could be

• -haloacetophenone, calculating the energy of each compound as the carbon–halogen bond is rotated through 10° increments in both the gas phase and in ethanol as reaction solvent (Figure 1) [10]. The fluorinated acetophenone showed significant differences in conformational energy to the chlorinated and brominated

• reactive conformations more accessible to the fluorinated acetophenone. Potential reasons for the different conformational preferences of the α-halogenated acetophenones were then examined. One possibility is that the increased electronegativity of fluorine induces a high dipole moment at small O=C–C–X

Nucleophilic dearomatization of 4-aza-6-nitrobenzofuroxan by CH acids in the synthesis of pharmacology-oriented compounds

• Alexey M. Starosotnikov,
• Dmitry V. Shkaev,
• Maxim A. Bastrakov,
• Ivan V. Fedyanin,
• Svyatoslav A. Shevelev and
• Igor L. Dalinger

Beilstein J. Org. Chem. 2017, 13, 2854–2861, doi:10.3762/bjoc.13.277

• described earlier [17][26][27]. Unlike for DNBF [15], no evidence of formation of any adduct was obtained on addition of an equimolar amount of acetone to a solution of ANBF in DMSO-d6. Moreover, reactions of 1 with acetone or acetophenone in the presence of 1 equiv of Et3N led to fast consumption of the

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

• the presence of Eosin Y under visible light irradiation (Scheme 2) [9]. Acetophenone derivatives with various substitution patterns as well as aliphatic or heteroaromatic ketones were equally well tolerated. This methodology offered the advantage of minimising the chlorination side reaction

Regiodivergent condensation of 5-alkoxycarbonyl-1H-pyrrol-2,3-diones with cyclic ketazinones en route to spirocyclic scaffolds

• Alexey Yu. Dubovtsev,
• Maksim V. Dmitriev,
• Аndrey N. Maslivets and
• Michael Rubin

Beilstein J. Org. Chem. 2017, 13, 2179–2185, doi:10.3762/bjoc.13.218

• ]. Keeping this in mind we decided to test the reactivity of ketazinones 17 that were obtained via condensation of cyclohexanediones 8 with hydrazone of acetophenone. We anticipated the formation of spirolactones 20 in this process, resulting from intramolecular transesterification involving the enol moiety

α-Acetoxyarone synthesis via iodine-catalyzed and tert-butyl hydroperoxide-mediateded self-intermolecular oxidative coupling of aryl ketones

• Liquan Tan,
• Cui Chen and
• Weibing Liu

Beilstein J. Org. Chem. 2017, 13, 1079–1084, doi:10.3762/bjoc.13.107

• , the reaction of acetophenone (1a) in the presence of an I2–TBHP system gave the desired product 2a in 46% yield. The yield increased to 71% when the reaction time was prolonged to 24 h (Table 1, entries 1–3). The reaction did not occur in the absence of I2 or Na2CO3, indicating that these species both

• indicated that the optimum reaction temperature is: 70 °C (Table 1, entries 19 and 20). After the optimization study, the generality of the optimum conditions with various substituted aryl ketones was investigated (Scheme 2). Initially, acetophenone derivatives 1a–h were used; various electron-donating (i.e

• desired product in relatively high yields (2f, 2g, and 2h). The position of a given substituent on the phenyl ring of acetophenone affected the reaction slightly, and para-substituted acetophenones gave better results than ortho- and meta-substituted acetophenones (2b, 2c, and 2d). The scope of this

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

• obtained from the reaction of o-phthalaldehyde (86) with acetophenone 87 (Scheme 28). Iron(III) complexes of 88a–d turned out to be promising candidates for potential photovoltaic or luminescence applications. An intramolecular hydroacylation, catalyzed by nickel(0)/N-heterocyclic carbenes leading to 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

• concentrations of 1 mmol L−1 in single-scan experiments. As a proof-of-concept, they studied the transfer hydrogenation process of acetophenone with isopropanol catalysed by iridium complexes. The reaction was performed in batch and the sample was introduced into the magnet with a pump and Teflon tubing to form

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

• resulted in the decomposition of 225 to give acetophenone (227) and tert-butanol (228). A three-step mechanism for this reaction was proposed (Scheme 68) [336][337]. The reaction commences with a base-mediated α-proton abstraction from 225 to form carbanion 226 and the latter decomposes to yield the tert

• -butoxide anion and acetophenone (227). These steps occur presumably in a concerted manner. Finally, the protonation of the tert-butoxide anion results in the formation of tert-butanol (228). As alternative bases Et3N [338][339], phosphorus ylides [340] and LiOH [341][342] can be used and the Kornblum

NeoPHOX – a structurally tunable ligand system for asymmetric catalysis

• Jaroslav Padevět,
• Marcus G. Schrems,
• Robin Scheil and
• Andreas Pfaltz

Beilstein J. Org. Chem. 2016, 12, 1185–1195, doi:10.3762/bjoc.12.114

• ligands and serine-based PHOX ligands A set of seven Ir-NeoPHOX catalysts was evaluated in the asymmetric hydrogenation of three alkenes and acetophenone phenylimine (Table 2). For comparison, the results previously reported for four related serine-based Ir-PHOX complexes are included in the table

Iodine-mediated synthesis of 3-acylbenzothiadiazine 1,1-dioxides

• Long-Yi Xi,
• Ruo-Yi Zhang,
• Lei Shi,
• Shan-Yong Chen and
• Xiao-Qi Yu

Beilstein J. Org. Chem. 2016, 12, 1072–1078, doi:10.3762/bjoc.12.101

• -acylbenzothiadiazine 1,1-dioxides from 2-aminobenzenesulfonamides and acetophenones via iodine-mediated sp3 C–H functionalization. Results and Discussion We commenced our studies by heating acetophenone (1a), 2-aminobenzenesulfonamide (2a) and I2 in DMSO for 12 h. To our delight, the desired product was isolated in 60

• biologically active benzothiadiazine 1,1-dioxides. Experimental Typical procedure for the synthesis of 3-acylbenzothiadiazine 1,1-dioxides: A mixture of acetophenone (0.040 mL, 0.33 mmol), I2 (0.057 g, 0.225 mmol) and 2-aminobenzenesulfonamide (0.051 g, 0.3 mmol) in DMSO (2 mL) was stirred at 110 °C under air

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

• enantioselectivities (up to 94% ee). A variety of substituted isatins were well tolerated under these conditions. In addition, the weak nucleophile acetophenone also reacted with isatins, giving the corresponding products with satisfactory results under the same conditions, although acetophenone was always considered

Scope and mechanism of the highly stereoselective metal-mediated domino aldol reactions of enolates with aldehydes

• M. Emin Cinar,
• Bernward Engelen,
• Martin Panthöfer,
• Hans-Jörg Deiseroth,
• Jens Schlirf and
• Michael Schmittel

Beilstein J. Org. Chem. 2016, 12, 813–824, doi:10.3762/bjoc.12.80

• product in the presence of base [41]. The variability in the ketone moiety proved to be rather restricted (Scheme 3). While in the case of propiophenone (1a) and butyrophenone (1f) moderate to good yields (≥50%) were obtained, the reaction with acetophenone (1e) did not furnish any domino aldol product at

Scope and limitations of the dual-gold-catalysed hydrophenoxylation of alkynes

• Adrián Gómez-Suárez,
• Yoshihiro Oonishi,
• Anthony R. Martin and
• Steven P. Nolan

Beilstein J. Org. Chem. 2016, 12, 172–178, doi:10.3762/bjoc.12.19

• as 10% of acetophenone, the corresponding hydration product. Furthermore, the formation of a new gold species, which was characterised as the previously reported σ,π-digold–acetylide species could also be observed. This diaurated species can be formed by reaction of [{Au(IPr)}2(µ-OH)][BF4] with

Synthesis and structures of ruthenium–NHC complexes and their catalysis in hydrogen transfer reaction

• Chao Chen,
• Chunxin Lu,
• Qing Zheng,
• Shengliang Ni,
• Min Zhang and
• Wanzhi Chen

Beilstein J. Org. Chem. 2015, 11, 1786–1795, doi:10.3762/bjoc.11.194

• ruthenium–NHC complexes presented above are stabilized by strong Ru–carbene bonds and contain 2–4 easily dissociating acetonitrile molecules, and are thus ideal catalysts. We tested their catalytic activities for transfer hydrogenation of ketones. Firstly, acetophenone was selected as the model substrate to

• evaluate the catalytic activities of complexes 1–3. The standard experiment was carried out at 80 °C with varied Ru loadings from 1 to 0.01 mol % and the results are summarized in Table 1. The reaction profiles show that acetophenone could be reduced to 1-phenylethanol in 89–99% yield within 0.5 h using 1

• the reaction time was extended to 1 and 3 h, respectively (Table 1, entries 3, 7, 11 and 4, 8, 12). At catalyst loadings of 0.01 mol %, TOF of 1–3 are 3000, 3233, and 3200 h−1 for transfer hydrogenation of acetophenone which are nearly identical to that of [Ru(MeCCmeth)2(CH3CN)2](BF4)2 (MeCCmeth = 1,1

Preparative semiconductor photoredox catalysis: An emerging theme in organic synthesis

• David W. Manley and
• John C. Walton

Beilstein J. Org. Chem. 2015, 11, 1570–1582, doi:10.3762/bjoc.11.173

• 64 but a significant quantity of ring opened byproduct was also formed. Carbonyl compounds are also good electron acceptors and so SCPC hydrogenations seemed likely. Actually there is a literature precedent for photocatalytic hydrogenation of acetophenone derivatives with TiO2 [80][81]. We studied a

The synthesis of active pharmaceutical ingredients (APIs) using continuous flow chemistry

• Marcus Baumann and
• Ian R. Baxendale

Beilstein J. Org. Chem. 2015, 11, 1194–1219, doi:10.3762/bjoc.11.134

• this challenging compound was reported in 2013 and aims to evaluate the benefits of flow chemistry in order to avoid shortcomings of previous batch synthesis efforts particularly in regard to scale up [93]. The investigation first involved the preparation of the key acetophenone starting material 112

A new and convenient synthetic way to 2-substituted thieno[2,3-b]indoles

• Roman A. Irgashev,
• Arseny A. Karmatsky,
• Gennady L. Rusinov and
• Valery N. Charushin

Beilstein J. Org. Chem. 2015, 11, 1000–1007, doi:10.3762/bjoc.11.112

• significant preparative interest, since the target compounds are formed from isatins 7 and ketones 8 in four steps in low yields. The formation of model thieno[2,3-b]indole 12a from 1-ethylisatin (7a) and acetophenone (8a) has been studied in details, as the first step of our research (Scheme 3). The

• phosphorane derivative 13 which is formed by pre-functionalization of acetophenone (8a), and this approach can be regarded as an alternative synthetic route just in some specific cases. Thus, the two-step approach to convert isatins 7 into thieno[2,3-b]indoles 12 via intermediacy of 10 (Path B) has been

• acetophenone (8a) according to the synthetic procedure described above. Isatin 7c containing an n-hexyl substituent at the nitrogen atom has been applied to ensure a good solubility of the target product 12o, as well as of the intermediate 10o. It should be noted that bromination of 2-phenyl-substituted thieno

DBU-promoted carboxylative cyclization of o-hydroxy- and o-acetamidoacetophenone

• Wen-Zhen Zhang,
• Si Liu and
• Xiao-Bing Lu

Beilstein J. Org. Chem. 2015, 11, 906–912, doi:10.3762/bjoc.11.102

• corresponding products (Table 3, entries 2 and 3). The reactions using benzamido- (3d) and p-toluenesulfonamido- (3e) acetophenone gave complex mixtures and no carboxylative cyclization product was observed (Table 3, entries 4 and 5). A likely mechanism for the carboxylative cyclization of o

An intramolecular C–N cross-coupling of β-enaminones: a simple and efficient way to precursors of some alkaloids of Galipea officinalis

• Hana Doušová,
• Radim Horák,
• Zdeňka Růžičková and
• Petr Šimůnek

Beilstein J. Org. Chem. 2015, 11, 884–892, doi:10.3762/bjoc.11.99

• the starting substrates A simple retrosynthesis of enaminones 3 leads to the corresponding β-diketones 4 accessible through Claisen condensation of 3-phenylpropionic ester 5 with the appropriate acetophenone 6 (Scheme 3). The synthesis of ester 5 was accomplished according to Scheme 4. The classic

Copper-catalyzed cascade reactions of α,β-unsaturated esters with keto esters

• Zhengning Li,
• Chongnian Wang and
• Zengchang Li

Beilstein J. Org. Chem. 2015, 11, 213–218, doi:10.3762/bjoc.11.23

• hydride-catalyzed reductive aldolization of acetophenone [19]. Therefore, tert-butyl acrylate (1d) was used to replace methyl acrylate, and several biphosphorous ligands were screened for improving the diastereoselectivity (Table 3). Diastereomers of 3da were separated, which were subjected to further

• vs entry 1), and an effect of ligands on the diastereoselectivity of lactone was observed too. Xantphos was superior to other ligands. Overall, the diastereoselectivities were much lower than those in the reactions of tert-butyl acrylate with acetophenone and silane. The diastereoselectivity varied

Come-back of phenanthridine and phenanthridinium derivatives in the 21st century

• Lidija-Marija Tumir,
• Marijana Radić Stojković and
• Ivo Piantanida

Beilstein J. Org. Chem. 2014, 10, 2930–2954, doi:10.3762/bjoc.10.312