Switching the reaction pathways of electrochemically generated β-haloalkoxysulfonium ions – synthesis of halohydrins and epoxides

• Akihiro Shimizu,
• Ryutaro Hayashi,
• Yosuke Ashikari,
• Toshiki Nokami and
• Jun-ichi Yoshida

Beilstein J. Org. Chem. 2015, 11, 242–248, doi:10.3762/bjoc.11.27

• compatible with most organic compounds. Electrochemical oxidation [4][5][6][7][8][9][10][11] is a potent technique to generate and accumulate highly reactive cationic species in solution (the “cation pool” method) [12][13][14][15][16][17]. Although halogen cations are too unstable to accumulate in solution

3α,5α-Cyclocholestan-6β-yl ethers as donors of the cholesterol moiety for the electrochemical synthesis of cholesterol glycoconjugates

• Aneta M. Tomkiel,
• Adam Biedrzycki,
• Jolanta Płoszyńska,
• Dorota Naróg,
• Andrzej Sobkowiak and
• Jacek W. Morzycki

Beilstein J. Org. Chem. 2015, 11, 162–168, doi:10.3762/bjoc.11.16

• derivatives show similar reactivities to those of previously studied 3α,5α-cyclocholestan-6β-thioethers. Keywords: cholesterol; electrochemical oxidation; glycosylation; i-cholesteryl ethers; i-steroids; Introduction We have recently elaborated an electrochemical method for the preparation of glycosides and

• during electrochemical oxidation by cleavage of the carbon–oxygen bond in an intermediate radical-cation. For this reason, i-cholesteryl ethers seemed to be suitable donors of the cholesterol moiety for the electrochemical synthesis of cholesterol glycoconjugates. A series of i-cholesterol derivatives 6b

• oxidation currents are approximately equal to the half of oxidation current of 6d and also other investigated compounds. This is probably caused by the electrode blocking due to an adsorption of the oxidation products. The fact that the electrochemical oxidation of 6f and 6g starts at more negative

Cross-dehydrogenative coupling for the intermolecular C–O bond formation

• Igor B. Krylov,
• Vera A. Vil’ and
• Alexander O. Terent’ev

Beilstein J. Org. Chem. 2015, 11, 92–146, doi:10.3762/bjoc.11.13

• , arylethylenes, and arylacetylenes were used as precursors of the acyloxy fragment. The cross-dehydrogenative C–O coupling with 2-arylpyridines 4 proceeds also in the presence of the Cu(OAc)2/O2 system [40] and under electrochemical oxidation in the presence of Pd(II) salts [41]. The pyrimidine (acetoxylation of

Redox active dendronized polystyrenes equipped with peripheral triarylamines

• Toshiki Nokami,
• Naoki Musya,
• Tatsuya Morofuji,
• Keiji Takeda,
• Masahiro Takumi,
• Akihiro Shimizu and
• Jun-ichi Yoshida

Beilstein J. Org. Chem. 2014, 10, 3097–3103, doi:10.3762/bjoc.10.326

• unsuccessful. Low-temperature electrochemical oxidation of dendrimer 5 using the “cation pool” method [31][32][33][34][35][36][37][38][39][40][41][42][43][44][45][46][47] did not give the corresponding dendritic diarylcarbenium ion even, when subjected to excess capacitance (up to 5.0 F/mol). Next, we examined

• the “graft-from” approach (Figure 3). The low-temperature electrochemical oxidation of dendrimer 4 using the “cation pool” method was performed in CD2Cl2, and the resulting anodic solution was transferred to NMR tubes. Low-temperature NMR analysis indicated that an accumulation of dendritic

The Shono-type electroorganic oxidation of unfunctionalised amides. Carbon–carbon bond formation via electrogenerated N-acyliminium ions

• Alan M. Jones and
• Craig E. Banks

Beilstein J. Org. Chem. 2014, 10, 3056–3072, doi:10.3762/bjoc.10.323

• electrochemical oxidation of unfunctionalised amides (last comprehensively reviewed in 1984 by Prof. T. Shono) [10] to N-acyliminium ion intermediates and their application to synthetic challenges. The Shono electrooxidation route to N-acyliminium intermediates Shono and colleagues reported the first direct

Recent advances in the electrochemical construction of heterocycles

• Robert Francke

Beilstein J. Org. Chem. 2014, 10, 2858–2873, doi:10.3762/bjoc.10.303

• using electron transfer mediators (Scheme 1) play an important role. With regard to selectivity, the direct method is often complementary to typical chemical oxidations and reductions, since electrochemical oxidation or reduction proceeds via discrete electron transfer steps rather than atom transfer

New enzymatically polymerized copolymers from 4-tert-butylphenol and 4-ferrocenylphenol and their modification and inclusion complexes with β-cyclodextrin

• Adam Mondrzyk,
• Beate Mondrzik,
• Sabrina Gingter and
• Helmut Ritter

Beilstein J. Org. Chem. 2012, 8, 2118–2123, doi:10.3762/bjoc.8.238

• several studies, especially with regard to its electrochemical properties. After electrochemical oxidation of the Fe(II) ion to Fe(III) a one-electron transfer from the phenol moiety takes place, in which a proton is transferred simultaneously [20]. Furthermore, 4-ferrocenylphenol shows an antianemic

Efficient electroorganic synthesis of 2,3,6,7,10,11-hexahydroxytriphenylene derivatives

• Carolin Regenbrecht and
• Siegfried R. Waldvogel

Beilstein J. Org. Chem. 2012, 8, 1721–1724, doi:10.3762/bjoc.8.196

• . The shift of potentials is supported by cyclic voltammetry studies. Keywords: catechol; electrochemical oxidation; hexahydroxytriphenylene; ketals; propylene carbonate; Introduction The unique spectroscopic and geometric features of triphenylenes give rise to a variety of applications for this very

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

• , Wako, Saitama 351-0198, Japan 10.3762/bjoc.8.52 Abstract Glycosyl triflates with a 2,3-oxazolidinone protecting group were generated from thioglycosides by low-temperature electrochemical oxidation. The glycosyl triflates reacted with alcohols to give the corresponding glycosides β-selectively at low

• temperatures. However, α-selectivity was observed in the absence of base at elevated reaction temperatures. In situ generated triflic acid promotes the isomerization of β-products to α-products. Keywords: amino sugar; anomerization; electrochemical oxidation; glycosylation; thioglycoside; Introduction

• , play an important role in the stereoselective formation of both α- and β-isomers. We have developed an electrochemical method to generate and accumulate highly reactive glycosyl triflates by low-temperature electrochemical oxidation of thioglycosides [26][27][28][29][30]. Although Kerns and Ye have

Syntheses and applications of furanyl-functionalised 2,2’:6’,2’’-terpyridines

• Jérôme Husson and
• Michael Knorr

Beilstein J. Org. Chem. 2012, 8, 379–389, doi:10.3762/bjoc.8.41

• ], as catalysts [8], etc. On the other hand, five-membered heterocycles such as furan, pyrrole, selenophene, tellurophene or thiophene possess interesting features such as the capability to undergo chemical and electrochemical oxidation to afford polymers. These polymeric materials generally exhibit

A practical microreactor for electrochemistry in flow

• Kevin Watts,
• William Gattrell and
• Thomas Wirth

Beilstein J. Org. Chem. 2011, 7, 1108–1114, doi:10.3762/bjoc.7.127

• one-pot procedures to diaryliodonium salts known that involve both oxidation and ligand exchange directly from the aryl and iodoarene starting materials. The electrochemical oxidation of an iodoarene in the presence of another arene provides a quite general and simple one-step approach to the

Synthesis of 3-(quinolin-2-yl)- and 3,6-bis(quinolin-2-yl)-9H-carbazoles

• Yang Li and
• Wentao Gao

Beilstein J. Org. Chem. 2010, 6, 966–972, doi:10.3762/bjoc.6.108

• considered to be potential candidates for electronic devices, such as color displays, organic semiconductor lasers, and solar cells because of their reversible electrochemical oxidation [14][15][16][17][18][19][20]. Currently, there is a strong interest in the synthesis of novel heteroarylcarbazole

EPR and pulsed ENDOR study of intermediates from reactions of aromatic azides with group 13 metal trichlorides

• Giorgio Bencivenni,
• Riccardo Cesari,
• Daniele Nanni,
• Hassane El Mkami and
• John C. Walton

Beilstein J. Org. Chem. 2010, 6, 713–725, doi:10.3762/bjoc.6.84

• the degree of protonation, which can facilitate electron transfer (ET) [39][40]. It has also been reported that electrochemical oxidation of aromatic amines can generate the same radical cations which can polymerise giving oligo- and poly-anilines [41]. In view of the fact that product analyses [31

Reduction of arenediazonium salts by tetrakis(dimethylamino)ethylene (TDAE): Efficient formation of products derived from aryl radicals

• Mohan Mahesh,
• John A. Murphy,
• Franck LeStrat and
• Hans Peter Wessel

Beilstein J. Org. Chem. 2009, 5, No. 1, doi:10.3762/bjoc.5.1

• electrochemical oxidation of TDAE in acetonitrile occurs in two reversible one-electron oxidation steps, to TDAE+• 2 and TDAE++ 3 at −0.78 V and −0.61 V vs saturated calomel electrode (SCE). Recently, TDAE-promoted reduction of electron-deficient o- and p-nitrobenzyl chlorides [44][45][46][47], 1,2-bis

Generation of pyridyl coordinated organosilicon cation pool by oxidative Si-Si bond dissociation

• Toshiki Nokami,
• Ryoji Soma,
• Yoshimasa Yamamoto,
• Toshiyuki Kamei,
• Kenichiro Itami and
• Jun-ichi Yoshida

Beilstein J. Org. Chem. 2007, 3, No. 7, doi:10.1186/1860-5397-3-7

• the silicon atom. Eventually, Bu4NB(C6F5)4 was found to be an appropriate supporting electrolyte to generate and accumulate the organosilicon cation 3d. The 1H NMR spectrum of the solution obtained by the electrochemical oxidation of 1d in CH2Cl2 (containing 10% CD2Cl2) using Bu4NB(C6F5)4 at 0°C

• more effective than the 2-pyridylethyl group. The intramolecular coordination in the radical cation is supported by the DFT calculations as shown in Figure 2. It is also important to note that such coordination elongates the Si-Si bond and facilitates its dissociation. Preparative electrochemical

• oxidation of 1d was carried out to generate and accumulate the corresponding organosilicon cation 3d (Scheme 3). Nature of the counter anion was very important. When 1d was oxidized in the presence of Bu4NBF4, which is a common supporting electrolyte for the "cation pool" method, fluoride was introduced on