Green and sustainable approaches for the Friedel–Crafts reaction between aldehydes and indoles

• Periklis X. Kolagkis,
• Eirini M. Galathri and
• Christoforos G. Kokotos

Beilstein J. Org. Chem. 2024, 20, 379–426, doi:10.3762/bjoc.20.36

1-Butyl-3-methylimidazolium tetrafluoroborate as suitable solvent for BF₃: the case of alkyne hydration. Chemistry vs electrochemistry

• Marta David,
• Elisa Galli,
• Richard C. D. Brown,
• Marta Feroci,
• Fabrizio Vetica and
• Martina Bortolami

Beilstein J. Org. Chem. 2023, 19, 1966–1981, doi:10.3762/bjoc.19.147

• hexafluorophosphate (BMIm-PF6) as co-solvent with methanol and water to allow recycling of a phosphine-based Au(I) complex, as an efficient catalytic system for the hydration of terminal alkynes [87]. Moreover, the interesting properties of ILs have also been exploited to synthesize new solid polymeric catalysts for

• achieved with the BF4– counter anion (Table 3, entries 8–9 vs 2), suggesting PF6− and Tf2N− do not hinder the reactivity of BF3 in the hydration reaction. Based on these results, considering the higher cost of BMIm-Tf2N and BMIm-PF6, the preferred IL among those tested, in terms of both yield and cost, is

Palladium-catalyzed Sonogashira coupling reactions in γ-valerolactone-based ionic liquids

• László Orha,
• József M. Tukacs,
• László Kollár and
• László T. Mika

Beilstein J. Org. Chem. 2019, 15, 2907–2913, doi:10.3762/bjoc.15.284

• properties [21]. Accordingly, the Sonogashira reactions were also successfully performed in conventional ionic liquids such as [BMIM][PF6] [22][23][24][25], [BMIM][BF4] [23], [HMIM][BF4] [24], [EMIM][NTf2] [26], [nBuPy][X] (X = PF6–, BF4–, NO3–) [27], [DectBu3P][BF4] [28]. It was found that some of these

• PdCl2(PPh3)2 the treatment of 0.5 mmol 1a with 0.75 mmol of 2a afforded complete conversion of 1a in 40 min. Similar performance of PdCl2(PPh3)2 were reported by Ryu, when [BMIM][PF6] was used as reaction medium [26]; however, by the use of 10 times higher catalyst loading. The moisture content of the

• in isolated yields were observed (Table 4, Table 5 and Table 6) verifying the wide range of functional group tolerance by side of acetylenic substrates, as well. Same results were reported by Alper and co-workers, who perform this reaction in [BMIM][PF6] as alternative solvent [22]. The possible

A chemoenzymatic synthesis of ceramide trafficking inhibitor HPA-12

• Seema V. Kanojia,
• Sucheta Chatterjee,
• Subrata Chattopadhyay and
• Dibakar Goswami

Beilstein J. Org. Chem. 2019, 15, 490–496, doi:10.3762/bjoc.15.42

• synthesis of the title compound has been developed using an efficient and highly enantioselective lipase-catalyzed acylation in a hydrophobic ionic liquid, [bmim][PF6], followed by a diastereoselective asymmetric dihydroxylation as the key steps for incorporating the stereogenic centers. The further

• conversion to the appropriate intermediates and subsequent acylation with lauric acid furnished the target compound. Keywords: AD mix-β; [bmim][PF6]; DDQ; HPA-12; lipase; Introduction Ceramides belong to the family of sphingolipids (SLs) and are synthesized de-novo in the endoplasmic reticulum (ER) [1

• environment damaging organic solvent, but also increase the reaction rate, and provide many other technological advantages [49]. Towards this, we have chosen [bmim][BF4] and [bmim][PF6] as two model ionic liquids. Of them, [bmim][BF4] is water soluble, and [bmim][PF6] is immiscible with water. The acetylation

Bi-mediated allylation of aldehydes in [bmim][Br]: a mechanistic investigation

• Mrunesh Koli,
• Sucheta Chatterjee,
• Subrata Chattopadhyay and
• Dibakar Goswami

Beilstein J. Org. Chem. 2018, 14, 2198–2203, doi:10.3762/bjoc.14.193

• a similar result (entry 12), but activation with aqueous KF boosted the yield to 72% and reduced the reaction time (3 h, Table 1, entry 13). The reaction in [bmim][PF6] was sluggish and furnished 2a in 41% yield after 14 h (Table 1, entry 14), but the commonly used RTIL, [bmim][BF4] was totally

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

• [bmim]PF6 [247]. Benzoic acids 71a–d, 74 and phenyl esters 75a–d were reported as oxidation byproducts. Sn-containing mesoporous silica nanospheres (Sn-MSNSs) with uniform crater-like mesopores exhibited high activities in the Baeyer–Villiger oxidation of 2-adamantanone (45c) (Scheme 23) [248]. The

Reaction of allene esters with Selectfluor/TMSX (X = I, Br, Cl) and Selectfluor/NH₄SCN: Competing oxidative/electrophilic dihalogenation and nucleophilic/conjugate addition

• A. Srinivas Reddy and
• Kenneth K. Laali

Beilstein J. Org. Chem. 2015, 11, 1641–1648, doi:10.3762/bjoc.11.180

• ionic liquids [BMIM][NTf2] and [BMIM][PF6] as solvent, in the presence and absence of Selectfluor. Comparative product analysis studies demonstrate that the ability of Selectflour to promote oxidative/electrophilic dihalogenation/dithiocyanation with TMSX/NH4SCN (as observed previously for 1-arylallenes

• product 1d were isolated in comparable amounts along with a trace of 1c. Surprisingly no dihalogenation products were isolated when [BMIM][PF6] was employed as solvent. In this case 1c was isolated as a major product along with minor amounts of 1d. In an effort to enhance the oxidative power of

• /Selectfluor in MeCN, DMF, as well as in [BMIM][PF6] and [BMIM][NTf2]. The isomeric conjugate addition products 1l and 1m were isolated, with 1l as the major isomer. Unlike previous findings with 1-arylallenes [18], no dithiocyanation products were found irrespective of the choice of solvent (Scheme 4). In

Multicomponent reactions in nucleoside chemistry

• Mariola Koszytkowska-Stawińska and
• Włodzimierz Buchowicz

Beilstein J. Org. Chem. 2014, 10, 1706–1732, doi:10.3762/bjoc.10.179

• rather limited. Zhang et al. obtained a series of pyrimidine nucleoside-thazolidinone hybrids 15 from 5-formyl-3',5'-di-O-acetyl-2'-deoxyuridine (14), an arylamine and mercaptoacetic acid (Scheme 6) [65]. The reactions were performed in a ionic liquid ([bmim]PF6). Products 15 were obtained in good to

• . Reagents and reaction conditions: i. CuBr, THF, reflux, 0.5 h; ii. n-Bu4NF·3H2O, THF, rt, 2 h. Reagents and reaction conditions: i. [bmim][PF6], 80 °C, 5–8 h. Reagents and reaction conditions: i. EtOH, reflux, 24 h. Reagents and reaction conditions: i. NaOAc, H2O, 95 °C, 1–16 h; ii. NaOAc, H2O, 95 °C, 1 h

Efficient and selective chemical transformations under flow conditions: The combination of supported catalysts and supercritical fluids

• M. Isabel Burguete,
• Eduardo García-Verdugo and
• Santiago V. Luis

Beilstein J. Org. Chem. 2011, 7, 1347–1359, doi:10.3762/bjoc.7.159

• in ionic liquids (ILs) The immobilization of a Rh hydroformylation catalyst in [BMIM][PF6] has been reported by Cole-Hamilton to produce a significant decrease in the aldehyde selectivity, relative to toluene, while retaining the conversion and the l/b selectivity [60][61]. Changing to a scCO2–IL

Recent advances in the gold-catalyzed additions to C–C multiple bonds

• He Huang,
• Yu Zhou and
• Hong Liu

Beilstein J. Org. Chem. 2011, 7, 897–936, doi:10.3762/bjoc.7.103

• the gold-catalyzed cycloisomerization of α-hydroxyallenes 16 to 2,5-dihydrofurans 17 (Scheme 3) [25]. The best system was found to be AuBr3 in [BMIM][PF6]. The cycloisomerization of various alkyl- or arylsubstituted α-hydroxyallenes gave corresponding 2,5-dihydrofuran with complete axis-to-center

A review of new developments in the Friedel–Crafts alkylation – From green chemistry to asymmetric catalysis

• Magnus Rueping and
• Boris J. Nachtsheim

Beilstein J. Org. Chem. 2010, 6, No. 6, doi:10.3762/bjoc.6.6

• in high yields (Scheme 4). Other rare-earth trifluormethanesulfonates such as Nd(OTf)3 Yb(OTf)3 and Sm(OTf)3 showed similar reactivities and the reaction was later also performed in the ionic liquids [BMIM][OTf] and [BMIM][PF6] [6]. Next to benzyl alcohol, allyl alcohols, dibenzylethers as well as

Study of thioglycosylation in ionic liquids

• Jianguo Zhang and
• Arthur Ragauskas

Beilstein J. Org. Chem. 2006, 2, No. 12, doi:10.1186/1860-5397-2-12

• ionic liquid employed. The reactivity of glycosyl trichloroacetimidates and diethyl phosphites with alcohols in the presence and absence of lewis acids has been also recently been reported with several ionic liquids, including [bmim]PF6 and 1-n-hexyl-3-methylimidazolium trifluoromethanesulfonimidide.[8