Enabling technologies and green processes in cyclodextrin chemistry

• Giancarlo Cravotto,
• Marina Caporaso,
• Laszlo Jicsinszky and
• Katia Martina

Beilstein J. Org. Chem. 2016, 12, 278–294, doi:10.3762/bjoc.12.30

• preparation of CD thiols and thioethers is an emerging challenge because of the importance of intermediary azido derivatives [96] and favorable aggregation properties in nanomedicines and particularly the antidote Sugammadex [97]. The reaction between 6I-O-monotosyl-β-CD and various nucleophiles opens a new

Synthesis and nucleophilic aromatic substitution of 3-fluoro-5-nitro-1-(pentafluorosulfanyl)benzene

• Javier Ajenjo,
• Martin Greenhall,
• Camillo Zarantonello and
• Petr Beier

Beilstein J. Org. Chem. 2016, 12, 192–197, doi:10.3762/bjoc.12.21

• fluorination of nitro-substituted diaryl disulfides leading to 3- or 4-nitro-1-(pentafluorosulfanyl)benzenes [7][8][9][10]. This reaction is conducted in tens of kilogram scale in industry. The second method is known as Umemoto’s synthesis and starts with aromatic thiols or diaryl disulfides which are

Lewis acid-promoted hydrofluorination of alkynyl sulfides to generate α-fluorovinyl thioethers

• Davide Bello and
• David O'Hagan

Beilstein J. Org. Chem. 2015, 11, 1902–1909, doi:10.3762/bjoc.11.205

• Several methods for the synthesis of vinyl thioethers have been reported, including Wittig reactions [8], ionic and radical additions of thiols to alkynes [9] and coupling of 1-alkenyl halides with thiols, among others [10][11]. However, the literature for the preparation of α-fluorovinyl thioethers is

Preparative semiconductor photoredox catalysis: An emerging theme in organic synthesis

• David W. Manley and
• John C. Walton

Beilstein J. Org. Chem. 2015, 11, 1570–1582, doi:10.3762/bjoc.11.173

• . Recently Greaney and co-workers discovered that thiols 45 were also suitable donors with photoactivated TiO2 [67]. The thiol radical cations, formed on hole capture by the thiols, lost protons and generated thiyl radicals (Scheme 10). Benzenethiol, thiophenols and n-alkylthiols all afforded reduced alkene

• adducts 46 in high yields, but steric hindrance in branched thiols was deleterious. Alkenes with electron-releasing and electron-withdrawing substituents were tolerated. Interestingly, SCPC reactions also took place such that ethane and propanedithiols 47 coupled with two styrene molecules affording 1,2

• alkylations of alkenes with silanes [66] and thiols [67]. TiO2 reduction of a nitrochromenone derivative [70]. TiO2 mediated hydrodehalogenations and cyclizations of organic iodides [71]. TiO2 promoted hydrogenations of maleimides, maleic anhydride and aromatic aldehydes [79]. Mechanistic sketch of SCPC

One-pot odourless synthesis of thioesters via in situ generation of thiobenzoic acids using benzoic anhydrides and thiourea

• Mohammad Abbasi and
• Reza Khalifeh

Beilstein J. Org. Chem. 2015, 11, 1265–1273, doi:10.3762/bjoc.11.141

• ][26]. The reaction of active carboxylic acid derivatives with thiols [27][28][29][30][31][32][33][34][35][36][37][38][39][40][41] and the coupling of thiols with carboxylic acids using activating agents [42][43][44][45] have been mainly used for the synthesis of thioesters in organic synthesis. Thiol

• . On the other hand, the usual methods for preparing thioacids involve the action of toxic and unpleasant smelling, gaseous hydrogen sulfide on carboxylic acid derivatives [46][47]. Also, thioacids as thiols have a strong and repulsive smell. The in situ generation of thioacids using odourless, easy to

• preparation of alkane thiols using thiourea and alkyl halides is a well-known reaction in organic synthesis. In addition, two methods for the synthesis of thioacids from acyl chlorides using N,N-dimethylthioformamide [51] or thioacetamide [52] have been reported. As far as we know, a similar reaction using

Advances in the synthesis of functionalised pyrrolotetrathiafulvalenes

• Luke J. O’Driscoll,
• Sissel S. Andersen,
• Marta V. Solano,
• Dan Bendixen,
• Morten Jensen,
• Troels Duedal,
• Jess Lycoops,
• Cornelia van der Pol,
• Rebecca E. Sørensen,
• Karina R. Larsen,
• Kenneth Myntman,
• Christian Henriksen,
• Stinne W. Hansen and
• Jan O. Jeppesen

Beilstein J. Org. Chem. 2015, 11, 1112–1122, doi:10.3762/bjoc.11.125

• -cyanoethyl-protected thiols as a means to further functionalise MPTTFs with thioethers and (ii) copper-mediated N-arylation of both MPTTFs and BPTTFs. Results and Discussion An improved large-scale synthesis of N-tosyl-(1,3)-dithiolo[4,5-c]pyrrole-2-one (6) The known compound 6 [4][25] is an important

• both 2-cyanoethyl thioethers (4e) these reagents can be used to selectively deprotect and alkylate only one of the two thiols, affording MPTTF 4a (Scheme 4) [25]. Indeed, the direct preparation of 4h from 4e requires two iterative additions of base and alkylating agent. A wide range of other, more

Single-molecule conductance of a chemically modified, π-extended tetrathiafulvalene and its charge-transfer complex with F₄TCNQ

• Raúl García,
• M. Ángeles Herranz,
• Edmund Leary,
• M. Teresa González,
• Gabino Rubio Bollinger,
• Marius Bürkle,
• Linda A. Zotti,
• Yoshihiro Asai,
• Fabian Pauly,
• Juan Carlos Cuevas,
• Nicolás Agraït and
• Nazario Martín

Beilstein J. Org. Chem. 2015, 11, 1068–1078, doi:10.3762/bjoc.11.120

• tip and the substrate) are in contact, or in close enough proximity, one or more molecules of the compound adsorbed on the surface can bridge the two electrodes. This binding occurs through one of the terminal groups (thiols in this case) to each of the electrodes, hence forming a molecular junction

• plateaus was even lower in other cases. We stress that under the same experimental conditions, we obtained percentages of around 35% of well-defined plateaus for OPE3-dithiol. We have recently measured the conductance of a series of molecules based on a similar OPE3 backbone, also terminated with thiols

Peptide–polymer ligands for a tandem WW-domain, an adaptive multivalent protein–protein interaction: lessons on the thermodynamic fitness of flexible ligands

• Katharina Koschek,
• Vedat Durmaz,
• Oxana Krylova,
• Marek Wieczorek,
• Shilpi Gupta,
• Martin Richter,
• Alexander Bujotzek,
• Christina Fischer,
• Rainer Haag,
• Christian Freund,
• Marcus Weber and
• Jörg Rademann

Beilstein J. Org. Chem. 2015, 11, 837–847, doi:10.3762/bjoc.11.93

• ) was further converted by condensation with 2-N-maleimido-ethylamine and N-ethyl-N´-dimethylaminopropylcarbodiimide (EDC) [6]. The monovalent ligand peptide 2 was attached to the dextran carriers by nucleophilic addition of the thiols to the maleimide double bond furnishing peptide–polymer conjugates

DNA display of glycoconjugates to emulate oligomeric interactions of glycans

• Alexandre Novoa and
• Nicolas Winssinger

Beilstein J. Org. Chem. 2015, 11, 707–719, doi:10.3762/bjoc.11.81

• by Seitz and co-workers using thiols imbedded in the backbone of the PNA that were chemoselectively conjugated to a maleimide–glycan adduct [43]. Our first efforts in the area of glycan display aimed to demonstrate that a DNA template could be used to program the assembly of discrete PNA-tagged

Synthesis of tripodal catecholates and their immobilization on zinc oxide nanoparticles

• Franziska Klitsche,
• Julian Ramcke,
• Julia Migenda,
• Andreas Hensel,
• Tobias Vossmeyer,
• Horst Weller,
• Silvia Gross and
• Wolfgang Maison

Beilstein J. Org. Chem. 2015, 11, 678–686, doi:10.3762/bjoc.11.77

• needs to form a stable (in most cases covalent) connection to the target surface. Various bifunctional anchors have been reported for immobilization on different materials and nanoparticles. Basically, silane derivatives are used for glass surfaces [2][3], thiols for noble metal surfaces [4

Synthesis of 1,2-cis-2-C-branched aryl-C-glucosides via desulfurization of carbohydrate based hemithioacetals

• Henok H. Kinfe,
• Fanuel M. Mebrahtu,
• Mandlenkosi M. Manana,
• Kagiso Madumo and
• Mokela S. Sokamisa

Beilstein J. Org. Chem. 2015, 11, 583–588, doi:10.3762/bjoc.11.64

• hemithioacetal 3a (Scheme 1). During the deacetylation reaction the hemithioacetal 3a precipitated out of the methanol solution. Although most hemithioacetals (RCH(OH)SR’) are usually unstable and difficult to isolate as they dissociate to their corresponding aldehydes and thiols [22], hemithioacetal 3a was

Diastereoselective and enantioselective conjugate addition reactions utilizing α,β-unsaturated amides and lactams

• Katherine M. Byrd

Beilstein J. Org. Chem. 2015, 11, 530–562, doi:10.3762/bjoc.11.60

Natural phenolic metabolites with anti-angiogenic properties – a review from the chemical point of view

• Qiu Sun,
• Jörg Heilmann and
• Burkhard König

Beilstein J. Org. Chem. 2015, 11, 249–264, doi:10.3762/bjoc.11.28

• , which were reacted without further purification with R2SH thiols. The addition to the unsaturated system yielded the target compound 28 with different arylthiol groups under rearomatization. Acylphloroglucinol derivatives Acylphloroglucinols are typical secondary metabolites biosynthetically derived

First chemoenzymatic stereodivergent synthesis of both enantiomers of promethazine and ethopropazine

• Paweł Borowiecki,
• Daniel Paprocki and
• Maciej Dranka

Beilstein J. Org. Chem. 2014, 10, 3038–3055, doi:10.3762/bjoc.10.322

• very expensive, S-ethyl thioesters generate undesirable flavor of the formed thiols, employment of anhydrides yields free carboxylic acids causing enzyme deactivation, and finally application of conventional esters, despite their great availability and low price, could reverse acylation into

Organic chemistry on surfaces: Direct cyclopropanation by dihalocarbene addition to vinyl terminated self-assembled monolayers (SAMs)

• Malgorzata Adamkiewicz,
• David O’Hagan and
• Georg Hähner

Beilstein J. Org. Chem. 2014, 10, 2897–2902, doi:10.3762/bjoc.10.307

• (SAMs) are increasingly being used as a means of surface modification to alter properties in a tuneable manner [1][2][3]. The major classes of SAMs are those with adsorbed long chain alkyl thiols on gold surfaces/nanoparticles [4][5], or long chain alkylsilanes on silica surfaces [6][7]. Two general

Reversibly locked thionucleobase pairs in DNA to study base flipping enzymes

• Christine Beuck and
• Elmar Weinhold

Beilstein J. Org. Chem. 2014, 10, 2293–2306, doi:10.3762/bjoc.10.239

• thiols were added to a solution of the cross-linked duplex 1I6S-Et-S4U2 and the reaction was monitored by recording the UV spectrum as a function of time (Figure 5). DTT and BME are able to remove the alkyl linker and restore the thionucleobase specific UV absorption above 300 nm almost instantaneously

Chiral phosphines in nucleophilic organocatalysis

• Yumei Xiao,
• Zhanhu Sun,
• Hongchao Guo and
• Ohyun Kwon

Beilstein J. Org. Chem. 2014, 10, 2089–2121, doi:10.3762/bjoc.10.218

Photorelease of phosphates: Mild methods for protecting phosphate derivatives

• Sanjeewa N. Senadheera,
• Abraham L. Yousef and
• Richard S. Givens

Beilstein J. Org. Chem. 2014, 10, 2038–2054, doi:10.3762/bjoc.10.212

• , itself, is converted to an o-nitroso aldehyde (or ketone) that reacts with endogenous nucleophiles such as amines, thiols, etc. either present on the substrate, on target proteins or in the media. Poignant evidence of these limitations surfaced during mechanistic investigations of GAP protein GTPases and

Investigations of thiol-modified phenol derivatives for the use in thiol–ene photopolymerizations

• Sebastian Reinelt,
• Monir Tabatabai,
• Urs Karl Fischer,
• Norbert Moszner,
• Andreas Utterodt and
• Helmut Ritter

Beilstein J. Org. Chem. 2014, 10, 1733–1740, doi:10.3762/bjoc.10.180

• Synthesis and characterization of the thiol-modified bis- and trisphenol derivatives. Most synthetic routes for the preparation of thiols make use of alkyl halogenide or allyl derivatives as suitable precursors which are subsequently converted into the corresponding thiols [39]. In the present study, the

• synthesis of the phenol-based thiols (10a,b, 14a–c, 17) was accomplished by the radical addition of thioacetic acid to suitable allyl-modified precursors as depicted in Scheme 1 and Scheme 2. For the synthesis of 10a and 10b the well-established hydroxymethylation of bisphenol A was the starting point of

• derivatives 9a,b, 13a–c and 16 were successfully hydrolyzed under acidic conditions to obtain the thiols 10a,b, 14a–c and 17 as viscous oils. The corresponding FTIR spectra showed the disappearance of the strong C=O valence vibration at 1684 cm−1 and the simultaneous appearance of the weak S–H valence

Orthogonal dual thiol–chloroacetyl and thiol–ene couplings for the sequential one-pot assembly of heteroglycoclusters

• Michele Fiore,
• Gour Chand Daskhan,
• Baptiste Thomas and
• Olivier Renaudet

Beilstein J. Org. Chem. 2014, 10, 1557–1563, doi:10.3762/bjoc.10.160

• Abstract We describe the first one-pot orthogonal strategy to prepare well-defined cyclopeptide-based heteroglycoclusters (hGCs) from glycosyl thiols. Both thiol–chloroactetyl coupling (TCC) and thiol–ene coupling (TEC) have been used to decorate cyclopeptides regioselectively with diverse combination of

• ]. Herein we report a new strategy based on both thiol–chloroactetyl coupling (TCC) and thiol–ene coupling (TEC) to prepare hGCs from glycosyl thiols and cyclopeptide scaffolds displaying chloroacetyl (ClAc) and allyloxycarbonyl (Alloc) groups and vice versa. We demonstrate that cyclopeptides

• orthogonality of these two reactions for the growth of multifuncional dendrimers [22]. Results and Discussion Owing to their straightforward access, their high nucleophilicity and the stability of thioether conjugates, glycosyl thiols [23][24], α-D-ManSH 1 and β-D-GlcNAcSH 2 have been selected for this study

Molecular recognition of surface-immobilized carbohydrates by a synthetic lectin

• Melanie Rauschenberg,
• Eva-Corrina Fritz,
• Christian Schulz,
• Tobias Kaufmann and
• Bart Jan Ravoo

Beilstein J. Org. Chem. 2014, 10, 1354–1364, doi:10.3762/bjoc.10.138

• -terminated SAMs [33], by Diels–Alder reaction of cyclopentadienes and furans on maleimide-terminated SAMs [34], by thiol–ene click reaction of functionalized thiols on alkene-terminated SAMs [35] as well as by strain promoted cycloadditions on azide- and nitriloxide-terminated SAMs [36] using μCP. Homogenous

Automated solid-phase peptide synthesis to obtain therapeutic peptides

• Veronika Mäde,
• Sylvia Els-Heindl and
• Annette G. Beck-Sickinger

Beilstein J. Org. Chem. 2014, 10, 1197–1212, doi:10.3762/bjoc.10.118

• ]. Since then, the chemistry and application of this innovative drug delivery system has been developed crucially. Currently, there are many strategies to incorporate PEG into peptides. They can be attached to amino groups by acylation or alkylation, to thiols, hydroxy or amide groups [108]. These polymers

Atherton–Todd reaction: mechanism, scope and applications

• Stéphanie S. Le Corre,
• Mathieu Berchel,
• Hélène Couthon-Gourvès,
• Jean-Pierre Haelters and
• Paul-Alain Jaffrès

Beilstein J. Org. Chem. 2014, 10, 1166–1196, doi:10.3762/bjoc.10.117

• . However, an exception was made when considering the reaction with aliphatic thiols (e.g., n-alkylthiols) [33]. In all studied cases, the authors concluded that the first step (i.e., the formation of a phosphoryl chloride intermediate) was achieved with retention of configuration (Scheme 7-v). Then, a

Preparation of phosphines through C–P bond formation

• Iris Wauters,
• Wouter Debrouwer and
• Christian V. Stevens

Beilstein J. Org. Chem. 2014, 10, 1064–1096, doi:10.3762/bjoc.10.106

• .) or thiols that are reacted with halophosphines [31][32][33][34]. The diastereoisomers of menthylphosphinite boranes are popular synthetic intermediates for this approach (Scheme 1) [35]. The diastereomeric phosphinites 2, that were prepared from an alkyldichlorophosphine 1, were separated by

Tailoring of organic dyes with oxidoreductive compounds to obtain photocyclic radical generator systems exhibiting photocatalytic behavior

• Christian Ley,
• Julien Christmann,
• Ahmad Ibrahim,
• Luciano H. Di Stefano and
• Xavier Allonas

Beilstein J. Org. Chem. 2014, 10, 936–947, doi:10.3762/bjoc.10.92

• ]. Hydrogen donor coinitiators could be amines [33][34][35][36][37][38], ethers [39][40], sulfides [41][42][43] or thiols [43][44][45]. Electron transfer coinitiators could be borate salts [46][47], iodonium [48][49] or triazine [32] derivatives. However, if Type II PIS gain sensitivity in the visible part of