Oxidative radical ring-opening/cyclization of cyclopropane derivatives

• Yu Liu,
• Qiao-Lin Wang,
• Zan Chen,
• Cong-Shan Zhou,
• Bi-Quan Xiong,
• Pan-Liang Zhang,
• Chang-An Yang and
• Quan Zhou

Beilstein J. Org. Chem. 2019, 15, 256–278, doi:10.3762/bjoc.15.23

• nitrogen heterocyles 140 under acid-free conditions and used a well-defined catalyst [Ag(II)(bipy)2S2O8] at low loadings (Scheme 37) [117]. This finding indicated that the silver pyridine complex plays an important role in single electron oxidants of cyclopropanols. In the same year, a silver-catalyzed

An overview on recent advances in the synthesis of sulfonated organic materials, sulfonated silica materials, and sulfonated carbon materials and their catalytic applications in chemical processes

• Hashem Sharghi,
• Pezhman Shiri and
• Mahdi Aberi

Beilstein J. Org. Chem. 2018, 14, 2745–2770, doi:10.3762/bjoc.14.253

• are time-consuming and energy intensive, as well. Zou et al. reported an effective strategy for acid-free sulfonation of MWCNTs using the combination of ultrasonication and heating of the mixture of MWCNTs-COOH and (NH4)2SO4 solution. After washing the mixture with distilled water, the final product

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

• trifluoroacetates rather than phenols as products, phenols were readily obtained during the silica gel column chromatography. In 2013, an acid-free procedure for the regioselective hydroxylation of aryl ketones was reported by Kwong and co-workers [72]. They used Pd(OAc)2 as catalyst and PhI(OTFA)2 as oxidant

A versatile route to polythiophenes with functional pendant groups using alkyne chemistry

• Xiao Huang,
• Li Yang,
• Rikard Emanuelsson,
• Jonas Bergquist,
• Maria Strømme,
• Martin Sjödin and
• Adolf Gogoll

Beilstein J. Org. Chem. 2016, 12, 2682–2688, doi:10.3762/bjoc.12.265

• sensitive to acidic conditions. Considering the robust production of functional alkyne-EDOT and its chemical stability, pyEDOT 3 was thus selected as the precursor of choice for future synthetic and electrochemical studies. pyEDOT can be stored at room temperature over months in an acid-free environment

Economical and scalable synthesis of 6-amino-2-cyanobenzothiazole

• Jacob R. Hauser,
• Hester A. Beard,
• Mary E. Bayana,
• Katherine E. Jolley,
• Stuart L. Warriner and
• Robin S. Bon

Beilstein J. Org. Chem. 2016, 12, 2019–2025, doi:10.3762/bjoc.12.189

• with ice cold water until acid free, and then dried under reduced pressure. The crude product was further purified by recrystallisation from MeCN (≈ 100 mL) or EtOH (≈ 425 mL) to yield 6 as fine off-white needles. Yield from EtOH (10.37 g, 48.34 mmol, 82%), from MeCN (9.21 g, 42.89 mmol, 73%). Mp 193

Acid, silver, and solvent-free gold-catalyzed hydrophenoxylation of internal alkynes

• Marcia E. Richard,
• Daniel V. Fraccica,
• Kevin J. Garcia,
• Erica J. Miller,
• Rosa M. Ciccarelli,
• Erin C. Holahan,
• Victoria L. Resh,
• Aakash Shah,
• Peter M. Findeis and
• Robert A. Stockland Jr.

Beilstein J. Org. Chem. 2013, 9, 2002–2008, doi:10.3762/bjoc.9.235

• either electron-withdrawing or electron-donating groups were efficiently added using these catalysts. No silver salts, acids, or solvents were needed for the catalysis, and either microwave or conventional heating afforded moderate to excellent yields of the vinyl ethers. Keywords: acid-free; catalysis

• the addition reaction [11]. Additionally, these cationic gold species can be generated through the reaction of chlorogold compounds with silver salts [1][2][3][4]. Recently, there has been growing interest in developing approaches that generate a catalytically active species under acid-free and silver

Metal-mediated aminocatalysis provides mild conditions: Enantioselective Michael addition mediated by primary amino catalysts and alkali-metal ions

• Matthias Leven,
• Jörg M. Neudörfl and
• Bernd Goldfuss

Beilstein J. Org. Chem. 2013, 9, 155–165, doi:10.3762/bjoc.9.18

• seems to be clear that the zwitterionic chelate shown in Figure 1 is too inert to form imines with carbonylic compounds. The choice of alkali metal does not affect the ee very markedly and the ee’s obtained in Table 1 are in the moderate range (up to 47%). In order to elucidate if Lewis acid free imines

Two-directional synthesis as a tool for diversity-oriented synthesis: Synthesis of alkaloid scaffolds

• Kieron M. G. O’Connell,
• Monica Díaz-Gavilán,
• Warren R. J. D. Galloway and
• David R. Spring

Beilstein J. Org. Chem. 2012, 8, 850–860, doi:10.3762/bjoc.8.95

• that the Lewis acid remains bonded to the carbonyl of the enol form of the ester group after the first conjugate addition, there may be insufficient Lewis acid free in solution to activate the second ester group separately, leaving it effectively inert to conjugate addition (and Dieckmann cyclisation

Fifty years of oxacalix[3]arenes: A review

• Kevin Cottet,
• Paula M. Marcos and
• Peter J. Cragg

Beilstein J. Org. Chem. 2012, 8, 201–226, doi:10.3762/bjoc.8.22

• monomer or the recrystallized monomer. The formation of 3a was observed in the reaction of the unpurified monomer, but not under acid-free conditions. Moreover, in separate experiments MsOH, TsOH or glacial acetic acid (AcOH) were added to reactions involving the recrystallized monomer. MsOH or TsOH

One-pot four-component synthesis of pyrimidyl and pyrazolyl substituted azulenes by glyoxylation–decarbonylative alkynylation–cyclocondensation sequences

• Charlotte F. Gers,
• Julia Rosellen,
• Eugen Merkul and
• Thomas J. J. Müller

Beilstein J. Org. Chem. 2011, 7, 1173–1181, doi:10.3762/bjoc.7.136

• one-pot four-component syntheses toward pyrimidyl- and pyrazolylazulenes. Results and Discussion Recently, we reported a three-component synthesis leading to the formation of ynones by a conceptually novel glyoxylation–decarbonylative Sonogashira coupling sequence (Scheme 2) [47]. The Lewis acid free

Transition- metal/Lewis acid free synthesis of acyl benzothiophenes via C-C bond forming reaction

• Sarbani Pal,
• Mohammad Ashrafuddin Khan,
• P. Bindu and
• P. K. Dubey

Beilstein J. Org. Chem. 2007, 3, No. 35, doi:10.1186/1860-5397-3-35

• pharmacological interest. Synthesis of acyl benzothiophenes Probable mechanism for the acylation of benzothiophene Synthesis of acyl substituted benzothiophenes (3 &4) via acylation of benzothiophene (1) with alkyl/aryl acids Supporting Information Supporting Information File 42: Transition-metal/lewis acid free