A Lewis acid-promoted Pinner reaction

• Dominik Pfaff,
• Gregor Nemecek and
• Joachim Podlech

Beilstein J. Org. Chem. 2013, 9, 1572–1577, doi:10.3762/bjoc.9.179

• -nitrobenzyl alcohol (21, Table 2, entry 5) and 4-hydroxymethylbenzoic acid (26, Table 2, entry 6) were reacted with benzyl cyanide or acetonitrile and even with acrylonitrile. A protection of the carboxylic acid turned out to be not necessary. In contrast, a 4-methoxy-substituted benzyl alcohol 52, i.e., an

• electron-rich benzyl alcohol, furnished no carboxylic ester at all (Table 2, entry 15). Rather poor yields of the respective carboxylic esters were achieved, when unsubstituted benzyl alcohol (56) or 4-fluorobenzyl alcohol (64) were reacted with one of the carbonitriles (Table 3). Instead we isolated

Hypervalent iodine/TEMPO-mediated oxidation in flow systems: a fast and efficient protocol for alcohol oxidation

• Nida Ambreen,
• Ravi Kumar and
• Thomas Wirth

Beilstein J. Org. Chem. 2013, 9, 1437–1442, doi:10.3762/bjoc.9.162

• shortened reaction times. Several other oxidative processes have already been reported in flow chemistry [16]. Results and Discussion Benzyl alcohol was chosen as a substrate in order to examine the efficiency of the reaction and the microreactor flow system. In a batch reaction, the mixture of benzyl

• of two syringes driven by a syringe pump, a T-connector and a tubing reactor (PTFE tubing, length: 4 m, internal diameter: 0.75 mm) was used for the oxidation of benzyl alcohol to benzaldehyde. The tubing reactor was inserted in a water bath at constant temperature as shown in Figure 1. In all flow

• optimized reaction time of 4.5 min was then used to convert also a larger amount of benzyl alcohol (15 mmol) to benzaldehyde, which was isolated as the reaction product in 49% yield. These results provide further evidence that this flow process is effective for oxidation methods initially discovered and

Metal-free aerobic oxidations mediated by N-hydroxyphthalimide. A concise review

• Lucio Melone and
• Carlo Punta

Beilstein J. Org. Chem. 2013, 9, 1296–1310, doi:10.3762/bjoc.9.146

• absence of light, cumene was completely inert, thus proving the intervention of the catalysts in the oxidative cycle. This process was successfully employed in the selective oxidation of benzyl alcohol at room temperature, affording the corresponding aldehyde in 4 h, in accordance with the results

Aqueous reductive amination using a dendritic metal catalyst in a dialysis bag

• Jorgen S. Willemsen,
• Jan C. M. van Hest and
• Floris P. J. T. Rutjes

Beilstein J. Org. Chem. 2013, 9, 960–965, doi:10.3762/bjoc.9.110

• by HPLC analysis. An excess of benzaldehyde was used, because it was also partially reduced to benzyl alcohol in a side reaction. The optimal pH appeared to be 5, comparable with a similar catalyst published by Fukuzumi [29][30]. In the presence of the nondendritic catalyst 3, formation of the N

Utilizing the σ-complex stability for quantifying reactivity in nucleophilic substitution of aromatic fluorides

• Magnus Liljenberg,
• Tore Brinck,
• Tobias Rein and
• Mats Svensson

Beilstein J. Org. Chem. 2013, 9, 791–799, doi:10.3762/bjoc.9.90

• of carbocyclic as well as heterocyclic fluorinated substrates [4][5]. Anionic nucleophiles (anions of methanol, benzyl alcohol and hydrogen sulfide) were investigated, as well as neutral nucleophiles (amines). The accuracy was well within 1 kcal/mol and the predictions can be used in a quantitative

1-n-Butyl-3-methylimidazolium-2-carboxylate: a versatile precatalyst for the ring-opening polymerization of ε-caprolactone and rac-lactide under solvent-free conditions

• Astrid Hoppe,
• Faten Sadaka,
• Claire-Hélène Brachais,
• Gilles Boni,
• Jean-Pierre Couvercelle and
• Laurent Plasseraud

Beilstein J. Org. Chem. 2013, 9, 647–654, doi:10.3762/bjoc.9.73

• of ε-caprolactone (ε-CL) and rac-lactide (rac-LA) under solvent-free conditions and using 1-n-butyl-3-methylimidazolium-2-carboxylate (BMIM-2-CO2) as precatalyst is described. Linear and star-branched polyesters were synthesized by successive use of benzyl alcohol, ethylene glycol, glycerol and

• precatalyst. Results and Discussion Two solvent-free polymerization procedures were developed in this study, named methods A and B (Scheme 1). Four initiator alcohols, with an increasing number of OH functions, were successively used: benzyl alcohol (1), ethylene glycol (2), glycerol (3) or pentaerythritol (4

• and form linear (benzyl alcohol, ethylene glycol) and star-branched (glycerol, pentaerythritol) polyesters. In comparison to their linear analogues, star-branched polymers feature lower crystallinity, lower melt viscosities and smaller hydrodynamic volume [56][57][58]. The crystallinity (defined

Synthesis and ring openings of cinnamate-derived N-unfunctionalised aziridines

• Alan Armstrong and
• Alexandra Ferguson

Beilstein J. Org. Chem. 2012, 8, 1747–1752, doi:10.3762/bjoc.8.199

• for further functionalisation of this substrate. Reaction of benzyl alcohol yielded the β-benzyloxy amino-acid derivative 2e in 46%. The orthogonal benzyl protection could allow the free alcohol to be accessed selectively by hydrogenation protocols, leaving the tert-butyl ester intact. Products 2d and

Palladium-catalyzed substitution of (coumarinyl)methyl acetates with C-, N-, and S-nucleophiles

• Kalicharan Chattopadhyay,
• Erik Fenster,
• Alexander J. Grenning and
• Jon A. Tunge

Beilstein J. Org. Chem. 2012, 8, 1200–1207, doi:10.3762/bjoc.8.133

• halomethylcoumarin and highly stabilized nucleophiles or amines [6][7][8][9][10][11][12][13][14][15]. Due to the sensitivity and toxicity of related benzyl halides, there has been interest in catalytically activating hydroxymethylarene and heteroarenes (e.g., benzyl alcohol derivatives) toward reactions with

Multistep organic synthesis of modular photosystems

• Naomi Sakai and
• Stefan Matile

Beilstein J. Org. Chem. 2012, 8, 897–904, doi:10.3762/bjoc.8.102

• diphosphonates [20][21] for tetravalent anchoring on the ITO surface. The geminal diphosphonates 7 were synthesized from methylene bis(phosphonic dichloride) 8 (Scheme 1) [20][21]. Conversion with benzyl alcohol and pyridine as a base yielded tetrabenzyl methylene bisphosphonate 9. Activation with sodium hydride

Electrochemical generation of 2,3-oxazolidinone glycosyl triflates as an intermediate for stereoselective glycosylation

• Toshiki Nokami,
• Akito Shibuya,
• Yoshihiro Saigusa,
• Shino Manabe,
• Yukishige Ito and
• Jun-ichi Yoshida

Beilstein J. Org. Chem. 2012, 8, 456–460, doi:10.3762/bjoc.8.52

• (Table 2). In accordance with our previous results [26][29], high β-selectvity was observed with highly reactive alcohols (Table 2, entries 1 and 2). On the other hand, less nucleophilic alcohols, such as benzyl alcohol and CF3CH2OH, gave the corresponding glycosides in lower β-selectivity than methanol

Development of the titanium–TADDOLate-catalyzed asymmetric fluorination of β-ketoesters

• Lukas Hintermann,
• Mauro Perseghini and
• Antonio Togni

Beilstein J. Org. Chem. 2011, 7, 1421–1435, doi:10.3762/bjoc.7.166

• -dimethylaniline and benzyl alcohol yielding (+)-10-F in 77% yield (84.9% ee by HPLC), whose configuration has already been established by correlation with 12-F. Comparison of the elution order on a chiral HPLC column with the (+)-sign of the optical rotation implied an (S)-configuration of this sample, and

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

• alcohols has been developed by utilizing NaAuCl4. The benzylic and secondary alcohols (55 and 58) worked well under mild conditions with low catalyst loading (Scheme 11). The chiral benzyl alcohol 60 gave racemic ether 61, which suggested the intermediacy of a carbocation. Ye et al. reported an expedient

Construction of cyclic enones via gold-catalyzed oxygen transfer reactions

• Leping Liu,
• Bo Xu and
• Gerald B. Hammond

Beilstein J. Org. Chem. 2011, 7, 606–614, doi:10.3762/bjoc.7.71

• rearrangement of alkynyl arylaldehydes 13 to benzoxepinones 14 with good regioselectivity (Scheme 11) [47]. This transformation was effectively promoted by the addition of benzyl alcohol and the sequential addition of p-toluenesulfonic acid. However, in the absence of p-toluenesulfonic acid, benzyl ether 15 was

Photocycloaddition of aromatic and aliphatic aldehydes to isoxazoles: Cycloaddition reactivity and stability studies

• Axel G. Griesbeck,
• Marco Franke,
• Jörg Neudörfl and
• Hidehiro Kotaka

Beilstein J. Org. Chem. 2011, 7, 127–134, doi:10.3762/bjoc.7.18

• , isoxazole-carbonyl photocycloaddition products constitute another class of photochromic T-type systems (Scheme 7) [18]. Hydrogenation of 9a by palladium/charcoal did not lead to the expected aminoketone 10, but to the enamino ketone 11 and benzyl alcohol, indicating decomposition of 9a back to the starting

• treatment with lithium aluminium hydride (3 equiv) yielded complex mixtures with benzyl alcohol as one of the main components. By contrast, no reaction could be observed in presence of sodium borohydride or sodium cyanoborohydride. Attempted reduction with sodium triacetoxyborohydride led to decomposition

Synthesis of 5-(6-hydroxy-7H-purine-8-ylthio)- 2-(N-hydroxyformamido)pentanoic acid

• Yanmei Zhang,
• Greg Elliot,
• Adrian Saldanha,
• Igor Tsigelny,
• Dennis Carson and
• Wolf Wrasidlo

Beilstein J. Org. Chem. 2010, 6, 742–747, doi:10.3762/bjoc.6.93

• , was added 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (EDC, 475.0 mg, 2.48 mmol) followed by DMAP (302.0 mg, 2.48 mmol). After stirring at 0 °C for 30 min, benzyl alcohol (402.0 mg, 3.72 mmol) was added. The reaction mixture was stirred at 0 °C for 1 h, then warmed to room temperature

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

• reaction was found by accident, this was probably the first description of a catalytic FC alkylation utilizing a benzyl alcohol. The first systematic investigations of catalytic FC benzylations were performed independently in 1996 and 1997 by Fukuzawa [3][4] and Shimizu et al. [5]. While the latter used 10

• 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

• . Furthermore, an efficient intramolecular variant of this procedure starting from biaryl benzyl alcohol 23 led to substituted fluorenes 24 which have shown to be valuable scaffolds for blue light emitting polymers (Scheme 11A) [46]. A similar route to fluorenes and other annulated cycloalkanes 26 was

A biphasic oxidation of alcohols to aldehydes and ketones using a simplified packed- bed microreactor

• Andrew Bogdan and
• D. Tyler McQuade

Beilstein J. Org. Chem. 2009, 5, No. 17, doi:10.3762/bjoc.5.17

• outlet (Figure 2B). The effective mixing was later supported by the high yields and conversions that were achieved for this biphasic reaction. Preliminary reactions were performed using benzyl alcohol as the test substrate in order to establish the optimal flow conditions (Scheme 3). A solution of benzyl

• to residence time, see Supporting Information File 1. During our optimization studies, it was shown that a total flow rate of 100 µL min−1 (aqueous flow rate 56 µL min−1 and organic flow rate 44 µL min−1, approximately 4.8 min residence time) afforded quantitative conversion of benzyl alcohol to

• flow conditions for the benzyl alcohol oxidation, a number of different substrates were examined to test the generality of the AO-TEMPO packed-bed microreactor. High conversions were achieved when using both aromatic and aliphatic alcohols (Table 1, Entries 1–6). Secondary alcohols, which are known to

Convenient method for preparing benzyl ethers and esters using 2-benzyloxypyridine

• Susana S. Lopez and
• Gregory B. Dudley

Beilstein J. Org. Chem. 2008, 4, No. 44, doi:10.3762/bjoc.4.44

• of benzyl trichloroacetimidate using triflic acid, except that alkylation under neutral conditions is compatible with acid- (and base-) sensitive substrates. Results and Discussion 2-Benzyloxypyridine was prepared in 97% yield by heating a mixture of benzyl alcohol, 2-chloropyridine (1.1 equiv), and

• protocols. Experimental 2-Benzyloxypyridine (2): A mixture of benzyl alcohol (11.7 g, 0.108 mol, 1.0 equiv), 2-chloropyridine (13.5 g, 0.119 mol, 1.1 equiv), KOH (20.0 g, 0.356 mol, 3.3 equiv, ground with a mortar and pestle), and anhydrous toluene (210 mL) was heated at reflux (bath temperature: 130 °C

Synthesis of imidazol- 1-yl-acetic acid hydrochloride: A key intermediate for zoledronic acid

• Santosh Kumar Singh,
• Narendra Manne,
• Purna Chandra Ray and
• Manojit Pal

Beilstein J. Org. Chem. 2008, 4, No. 42, doi:10.3762/bjoc.4.42

• KOH-K2CO3 followed by ester hydrolysis in water at 100 °C [10]. In another process [8] for the preparation of zoledronic acid, a benzyl ester of imidazole-1-yl-acetic acid 4 was prepared by reacting imidazole (1) with benzyl chloroacetate generated in situ from benzyl alcohol and chloroacetyl chloride

Vinylogous Mukaiyama aldol reactions with 4-oxy-2-trimethylsilyloxypyrroles: relevance to castanospermine synthesis

• Roger Hunter,
• Sophie C. M. Rees-Jones and
• Hong Su

Beilstein J. Org. Chem. 2007, 3, No. 38, doi:10.1186/1860-5397-3-38

• can present problems in end-game aspects of total synthesis. Thus it was decided to change methyl to the more deprotection-friendly benzyl group. Synthesis of benzyl pyrrolinone 4e was readily achieved by heating 4a with excess benzyl alcohol at 80°C in an acid-catalysed (p-TsOH) exchange with in

m-Iodosylbenzoic acid – a convenient recyclable reagent for highly efficient aromatic iodinations

• Andreas Kirschning,
• Mekhman S. Yusubov,
• Roza Y. Yusubova,
• Ki-Whan Chi and
• Joo Y. Park

Beilstein J. Org. Chem. 2007, 3, No. 19, doi:10.1186/1860-5397-3-19

• diiodinated benzyl alcohol 8n in good yield. Oxidation of the alcohol group was not observed. Based on related iodine(III)-mediated iodinations of arenas [12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37] we suggest that the hydrated form of 6 oxidizes

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

• glycosyl donors. Glycosylation of 1 and 2 with various alcohols in [bmim]BF4 with methyl triflate. Glycosidation of 1 and benzyl alcohol in [bmim]BF4 with methyl triflate and water. a-c. The percentage of hydrolyzed methyl trifluoromethanesulfonate in DMSO, CDCl3, and [bmim]BF4. Supporting Information