Ruthenium-based olefin metathesis catalysts with monodentate unsymmetrical NHC ligands

• Veronica Paradiso,
• Chiara Costabile and
• Fabia Grisi

Beilstein J. Org. Chem. 2018, 14, 3122–3149, doi:10.3762/bjoc.14.292

• relevant than electronic effects. Catalysts 136–142 were tested in the RCEYM of 127, in the RCM of 129 and in the CM of 13 and 14 (Table 5, entry 3). According to the experimental results, mesityl-bearing catalysts generally gave better yields than Dipp-containing analogues. In the presence of 136–138, a

Synthesis of unnatural α-amino esters using ethyl nitroacetate and condensation or cycloaddition reactions

• Glwadys Gagnot,
• Vincent Hervin,
• Eloi P. Coutant,
• Sarah Desmons,
• Racha Baatallah,
• Victor Monnot and
• Yves L. Janin

Beilstein J. Org. Chem. 2018, 14, 2846–2852, doi:10.3762/bjoc.14.263

• with an O-alkylation reaction which leads, via a rearrangement, to the corresponding aryl ester byproduct [7][8]. The proportion between the C-alkylation (leading to the expected acrylate) and this O-alkylation is most certainly governed by the electronic effects of the substituent on the aryl group

Oxidative and reductive cyclization in stiff dithienylethenes

• Michael Kleinwächter,
• Ellen Teichmann,
• Lutz Grubert,
• Martin Herder and
• Stefan Hecht

Beilstein J. Org. Chem. 2018, 14, 2812–2821, doi:10.3762/bjoc.14.259

• to be restricted to DTEs with strongly electron-withdrawing groups. We found that the electronic effects of an extended π-system lead to similar results. As such, the bis(4-(9,9-dimethyl-9H-fluoren-2-yl)phenyl)-substituted DTE-PhFluorene undergoes reductive as well as oxidative cyclization (Figure 5

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

• allows us to scrutinize the interplay between electronic effects and redox potential caused by ligand modifications within the series of Co4O4 cubane clusters. The ligand modification strategy developed here provides a rational, precise and cost-effective way for the chemical design and synthesis of

Asymmetric Michael addition reactions catalyzed by calix[4]thiourea cyclohexanediamine derivatives

• Zheng-Yi Li,
• Hong-Xiao Tong,
• Yuan Chen,
• Hong-Kui Su,
• Tangxin Xiao,
• Xiao-Qiang Sun and
• Leyong Wang

Beilstein J. Org. Chem. 2018, 14, 1901–1907, doi:10.3762/bjoc.14.164

• nitrostyrene 7a lacking substituents has minimal steric hindrance and tends to bind with the calixarene cavity by supramolecular host–guest interactions which could further improve the enantioselectivity. In addition, electronic effects of the substituents on the aromatic ring showed a significant influence on

Water-soluble SNS cationic palladium(II) complexes and their Suzuki–Miyaura cross-coupling reactions in aqueous medium

• Alphonse Fiebor,
• Richard Tia,
• Banothile C. E. Makhubela and
• Henok H. Kinfe

Beilstein J. Org. Chem. 2018, 14, 1859–1870, doi:10.3762/bjoc.14.160

• enhanced catalytic activity observed for 17a, which thus implies that the catalytic activity is influenced by steric as opposed to electronic effects. On the contrary, carrying out the reactions under otherwise identical conditions but with the presence of TBAB, the activity of the catalysts was reversed

Investigations of alkynylbenziodoxole derivatives for radical alkynylations in photoredox catalysis

• Yue Pan,
• Kunfang Jia,
• Yali Chen and
• Yiyun Chen

Beilstein J. Org. Chem. 2018, 14, 1215–1221, doi:10.3762/bjoc.14.103

• trifluoroborate 4b and primary alkyl trifluoroborate 4c, in which the deboronative alkynylation with unsubstituted BI-alkynes already gave good results. The electronic effects on the benziodoxoles were less significant and fluctuated within the 5% yield range: The alkynylation adducts 5b and 5c were obtained in

Are dispersion corrections accurate outside equilibrium? A case study on benzene

• Tim Gould,
• Erin R. Johnson and
• Sherif Abdulkader Tawfik

Beilstein J. Org. Chem. 2018, 14, 1181–1191, doi:10.3762/bjoc.14.99

• than the pairwise C10 contribution [41] and consequently is negligible for most applications compared to 3-body electronic effects [42][43][44]. Mathematically, the ATM treatment is most applicable when the energy contribution from 3rd and higher order terms converge rapidly as a function of inverse

Synthetic avenues towards a tetrasaccharide related to Streptococcus pneumonia of serotype 6A

• Aritra Chaudhury,
• Mana Mohan Mukherjee and
• Rina Ghosh

Beilstein J. Org. Chem. 2018, 14, 1095–1102, doi:10.3762/bjoc.14.95

• the central gluco-rhamno disaccharide the benzylidene protected glucosyl donor (Figure 2) was selected, because the induction of the 1,2-cis selectivity in benzylidene-protected substrates via torsional/electronic effects have already been recognized [28]. The galactosyl trichloroacetimidate donor 2

Selective carboxylation of reactive benzylic C–H bonds by a hypervalent iodine(III)/inorganic bromide oxidation system

• Toshifumi Dohi,
• Shohei Ueda,
• Kosuke Iwasaki,
• Yusuke Tsunoda,
• Koji Morimoto and
• Yasuyuki Kita

Beilstein J. Org. Chem. 2018, 14, 1087–1094, doi:10.3762/bjoc.14.94

• acetoxylation at the activated benzyl carbon adjacent to an oxygen atom proceeded smoothly as shown by the formation of the pseudo acetal 2g (Table 2, entry 6). Diphenylmethane and its derivatives were very good substrates for our system and were less sensitive to the electronic effects of the aromatic ring

Recent advances in synthetic approaches for medicinal chemistry of C-nucleosides

• Kartik Temburnikar and
• Katherine L. Seley-Radtke

Beilstein J. Org. Chem. 2018, 14, 772–785, doi:10.3762/bjoc.14.65

• modified nucleosides arise from changes in hydrogen bonding motifs, electronic effects, hydrophobic interactions, acid-base properties and chemical reactivity [25][26][27][28][29][30][31][32][33][34][35][36][37]. One such modification is the change in the nature of the glycosidic bond [29][37]. Although

Novel amide-functionalized chloramphenicol base bifunctional organocatalysts for enantioselective alcoholysis of meso-cyclic anhydrides

• Lingjun Xu,
• Shuwen Han,
• Linjie Yan,
• Haifeng Wang,
• Haihui Peng and
• Fener Chen

Beilstein J. Org. Chem. 2018, 14, 309–317, doi:10.3762/bjoc.14.19

• chloramphenicol scaffold. Electronic effects were first investigated. Generally, electron deficient catalysts gave better reactivity and enantioselectivity than electron-rich variants (Table 1, entries 1–9). Among them, 7i performed best with 95% yield and 92% ee in 17 h (Table 1, entry 9). The surprising

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

• -methylphenylglycinol (1b) and 2-chlorophenylglycinol (1c) delivered the corresponding imines in 68% yield (Table 2, entries 2 and 3). The meta-fluoro derivative provided imine 7d in 60% yield (Table 2, entry 4). Electronic effects were studied by examining a series of para-substituted phenylglycinol derivatives (Table

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

• moieties, then a molar optical rotation as large as ca. −80 deg dm−1 M−1 should be expected. By analogy with what observed for polysaccharides [41][42], differences with the observed values might be in principle ascribed to either electronic effects, or conformational rearrangements of the overall

• macrocycle structure. However, the fact that Θ2, Θ3 and Θ4 values are similar indicates that extensive deprotonation of the macrocycle has a minor outcome; therefore, a significant contribution from electronic effects may be ruled out. On the other hand, large conformational rearrangements deriving from

Mechanochemical synthesis of thioureas, ureas and guanidines

• Vjekoslav Štrukil

Beilstein J. Org. Chem. 2017, 13, 1828–1849, doi:10.3762/bjoc.13.178

• electronic effects exerted by different substituents, or liquid or solid character of the starting materials. Interestingly, in most cases a simple manual mechanical agitation of the reaction mixtures in a mortar provided products after only a few minutes of grinding. However, the combination of an electron

Photocatalyzed synthesis of isochromanones and isobenzofuranones under batch and flow conditions

• Manuel Anselmo,
• Lisa Moni,
• Hossny Ismail,
• Davide Comoretto,
• Renata Riva and
• Andrea Basso

Beilstein J. Org. Chem. 2017, 13, 1456–1462, doi:10.3762/bjoc.13.143

• , entry 7). Apparently, the electronic effects of the substituents of the diazonium salt play a major role, especially when considering the reactivity of benzenediazonium tetrafluoroborate 11c which, upon reaction with 2-ethoxycarbonylstyrene (12a), furnished only traces of the products, showing a

Phosphorus pentasulfide mediated conversion of organic thiocyanates to thiols

• Chandra Kant Maurya,
• Avik Mazumder and
• Pradeep Kumar Gupta

Beilstein J. Org. Chem. 2017, 13, 1184–1188, doi:10.3762/bjoc.13.117

• potassium thiocyanate in refluxing propylene glycol [19]. Simple short chain thiocyanates were found to react rapidly to give the corresponding thiols. In comparison to the alkyl substrates, the benzyl derivative reacted sluggishly possibly due to electronic effects which was further evident by the longer

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

• predominantly occurred at the position ortho to the aniline group. A mechanism investigation showed that the different regioselectivity was controlled by steric and electronic effects. In 2015, Hong and co-workers developed a C–H hydroxylation protocol for flavones; their work is of importance because the

Selective and eco-friendly procedures for the synthesis of benzimidazole derivatives. The role of the Er(OTf)₃ catalyst in the reaction selectivity

• Natividad Herrera Cano,
• Jorge G. Uranga,
• Mónica Nardi,
• Antonio Procopio,
• Daniel A. Wunderlin and
• Ana N. Santiago

Beilstein J. Org. Chem. 2016, 12, 2410–2419, doi:10.3762/bjoc.12.235

• show that the electronic effects of the substituents present in the aldehydes play a significant role in the reaction pathway. The 1,2-disubstituted benzimidazoles were obtained when electron-rich aldehydes were used, while 2-monosubstituted benzimidazoles were obtained from the reaction with electron

Experimental and theoretical investigations into the stability of cyclic aminals

• Edgar Sawatzky,
• Antonios Drakopoulos,
• Martin Rölz,
• Christoph Sotriffer,
• Bernd Engels and
• Michael Decker

Beilstein J. Org. Chem. 2016, 12, 2280–2292, doi:10.3762/bjoc.12.221

• investigations into their stability towards hydrolysis depending on the pH value are lacking. Results: A set of cyclic aminals was synthesized and their stability quantified by kinetic measurements. Steric and electronic effects were investigated by choosing appropriate groups. Both molecular mechanics (MM) and

• density functional theory (DFT) based studies were applied to support and explain the results obtained. Rapid decomposition is observed in acidic aqueous media for all cyclic aminals which occurs as a reversible reaction. Electronic effects do not seem relevant with regard to stability, but the magnitude

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

• ). Regiocontrol of the nitroso hetero-Diels–Alder reaction As discussed above, the nitroso hetero-Diels–Alder reaction can be highly regioselective due to the influences of diene substituents and electronic effects. However, reports on the specific regiocontrol of the reaction are rare. In general, the

• results from various electronic effects and the stereoselectivity can be influenced by the use of chiral dienes or dienophiles or the application of asymmetric catalysis. These methods, mainly the last one, take place in solution, while the solid-phase approaches described in the literature were not

Flow carbonylation of sterically hindered ortho-substituted iodoarenes

• Carl J. Mallia,
• Gary C. Walter and
• Ian R. Baxendale

Beilstein J. Org. Chem. 2016, 12, 1503–1511, doi:10.3762/bjoc.12.147

• and trifluoromethyl groups may be inferred (Scheme 4, 11, 13). A more pronounced decrease in yield was obtained for substrates 14 and 15 (Scheme 4, 63% and 60%, respectively) probably due to the larger size of these groups and as well as electronic effects (the more electron withdrawing

• substituents or electron-donating groups giving better yields (Scheme 4, compounds 17, 19–21) than the more electron-withdrawing CF3 group (Scheme 4, compound 18). In the case of 22 the attached aromatic ring introduces both the ortho substituted sterics and the electronic effects from the additional aromatic

• of ortho-substituted substrates giving moderate to good yields. Comparison of 22 with 32 also showed that the steric encumbrance on the ortho position has an effect on the yield even when other electronic effects are in place such as those coming from the additional aromatic ring attached. A scale-up

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

• -acetyl-2H-chromen-2-ones bearing an electron-withdrawing group gave the products in lower yields and with low ee values. In contrast, good reactivity and high enantioselectivity were observed for those with a electron-donating methoxy group probably due to the electronic effects. The final products

The synthesis of functionalized bridged polycycles via C–H bond insertion

• Jiun-Le Shih,
• Po-An Chen and
• Jeremy A. May

Beilstein J. Org. Chem. 2016, 12, 985–999, doi:10.3762/bjoc.12.97

• that have found that heteroatoms accelerate C–H bond insertion at adjacent carbons. The Lee group performed further studies on the electronic effects of the oxygen on the rate of bond insertion, and concluded that the ability of the oxygen lone pair to align with the σ* orbital of the C–H bond targeted

Enantioselective carbenoid insertion into C(sp³)–H bonds

• J. V. Santiago and
• A. H. L. Machado

Beilstein J. Org. Chem. 2016, 12, 882–902, doi:10.3762/bjoc.12.87

• efforts to better comprehend the scope of this catalytic system, especially on features concerning the BARF salt effect [43][44] and electronic effects on the aromatic rings of the chiral ligands [45]. In 2014, Maguire at al reported the syntheses of N-heterocycles by the enantioselective insertion of