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Lewis acid-catalyzed reactions of 2-substituted cyclopropane 1,1-dicarboxylates with 2-naphthols is reported. The reaction exhibits tunable selectivity depending on the nature of Lewis acid employed and proceed as a dearomatization/rearomatization sequence. With Bi(OTf)3 as the Lewis acid, a highly selective dehydrative [3+2] cyclopentannulation takes place leading to the formation of naphthalene-fused cyclopentanes. Interestingly, engaging Sc(OTf)3 as the Lewis acid, a Friedel-Crafts-type addition of 2-naphthols to cyclopropanes takes place, thus affording functionalized 2-naphthols. Both reactions furnished the target products in high regioselectivity and moderate to high yields.

The transition-metal-free procedure for the three-component coupling of aziridines, arynes and aldehydes affords N-aryl α-amino epoxides in moderate to good yields and diastereoselectivities.

A series of boronic acid-containing saccharide receptors was synthesised via copper catalysed azide–alkyne cycloaddition (CuAAC) reactions. Their saccharide binding capacity was studied by 1H and 11B NMR spectroscopy titrations and isothermal titration calorimetry (ITC) techniques. Fluorescent sensors were generated by linking a phenylboronic acid (PBA) receptor with fluorophores via a triazole-linker. Fluorescence titrations with fructose revealed that the substitution pattern about the PBA influences the fluorescence response to saccharides. Titrations studied by 1H NMR spectroscopy suggested that fructose binding is enhanced when the aromatic ring bearing the boronic acid has the triazole-containing substituent at the ortho position. No evidence of either a dative N–B bond or solvent insertion (between B and N) was observed by 11B NMR spectroscopy. These results demonstrate that synthetic accessible triazole receptors may allow rapid sensor synthesis, screening and discovery.

The application of the highly efficient ruthenium catalyst [Ru(CO)2{P(p-CF3–C6H4)3}2(O2CPh)2] (1) in the selective syn-addition of carboxylic acids to internal alkynes, yielding valuable trisubstituted enol esters with (E)-configuration, is described. All reactions feature excellent stereoselectivities and good regioselectivities. The regioselectivity is dictated by electronic and steric aspects of the alkyne substituents and the acidity of the carboxylic acid. The catalytic activity can be significantly increased by the addition of catalytic amounts of B(C6F5)3. Relative to known catalysts for the synthesis of (E)-enol esters, this methodology offers improved selectivity and requires lower catalyst loadings. Moreover, a broad range of alkynes and carboxylic acids can be successfully converted to their corresponding (E)-enol esters in high yields.

The aryne multicomponent coupling involving carboxylic acids initiated by aziridines as nucleophiles affords N-aryl β-amino alcohol derivatives while the application of azetidines as nucleophilic triggers furnishes N-aryl γ-amino alcohol derivatives.

Self-assembly and directed-assembly are two very important aspects of supramolecular chemistry. As a young postgraduate student working in Canada with Tom Fyles my introduction to Supramolecular Chemistry was through the self-assembly of phospholipid membranes to form vesicles for which we were developing unimolecular and self-assembling transporter molecules. The next stage of my development as a scientist was in Japan with Seiji Shinkai where in a "Eureka" moment, the boronic acid templating unit (directed-assembly) of Wulff was combined with photoinduced electron transfer systems pioneered by De Silva. The result was a turn-on fluorescence sensor for saccharides; this simple result has continued to fuel my research to the present day. Throughout my career as well as assembling molecules, I have enjoyed bringing together researchers in order to develop collaborative networks. This is where molecules meet people resulting in assemblies worth more than the individual "molecule" or "researcher". My role in developing networks with Japan was rewarded by the award of a Daiwa-Adrian Prize in 2013 and I was recently rewarded for developing networks with China with an Inaugural CASE Prize in 2015.

A general and stereospecific homologation strategy for the synthesis of heptopyranosides is reported. The strategy employs the Wittig olefination and proline-catalyzed α-aminoxylation to achieve one carbon elongation and stereoselective hydroxylation at the C6 position, respectively. The l-glycero- and d-glycero-heptopyranosides can be obtained with nearly perfect stereoselectivity. Further study reveals the difference in the chemical shift of the C6 proton of l/d-glycero-heptopyranosyl diastereomers, which is found to be useful for assignment of the configuration of heptopyranosides.

A transition-metal-free, three-component coupling involving N-substituted aziridines, arynes, and water promoted by trifluoroacetic acid (TFA) has been reported. The reaction furnished medicinally important N-aryl β-amino alcohol derivatives in moderate to good yields. In addition, the use of azetidines in this reaction afforded N-aryl γ-amino alcohol derivatives.

Boronic acids can bind with 1,2- or 1,3-diols to form five or six-membered cyclic complexes and also can interact with Lewis bases to generate boronate anions. Therefore, boronic acid functionalised compounds and materials are highly topical and now employed in (i) functional materials, (ii) for attaching/sensing bio-molecules and proteins, and (iii) for microbial electrochemistry as well as being widely developed as chemical sensors and tools in health diagnostics. In this review, we address the recent progress of boronic acid-based electrochemical sensors both in solution processes and surface processes for the detection of biological analytes. This feature article will be of interest to chemists, chemical engineers, biochemists, the sensor community, but also researchers working with protein and microbial systems.

The covalent boron-diol interaction enables elaborate design of boronic acid-based saccharide sensors. Over the last decade, this research topic has been well developed thanks to the integration of boronic acid chemistry with a range of techniques, including supramolecular chemistry, materials chemistry, surface modification, and nanotechnology. New sensing strategies and platforms have been introduced and remarkable progress has been achieved to fully utilize the unique property of boron-diol interaction and to improve the binding affinity towards different targets, especially under physiological conditions. In this review, the latest progress over the past 30 months (from late 2012 to early 2015) is highlighted and discussed to shed light on this versatile and promising platform for saccharide sensing.

Bisborodienes are transformed with various mono- and dialdehydes to form 1,4-diols with three to four stereogenic centers.

Oligosaccharides play important roles in nature; however, chemical synthesis of oligosaccharides is still difficult and not carried out in a fully automated manner. Among various methods, the activation of glycosyl donors by single electron transfer using electrochemical and photochemical methods has several benefits. In particular, electrochemical oxidation is a powerful method to activate glycosyl donors, including thioglycosides, which are one of the most popular class of glycosyl donors in modern chemical glycosylations. This review article covers the pioneering works of electrochemical glycosylations, other chemical glycosylations achieved by single electron transfer, and our recent approach to the automated solution-phase synthesis of oligosaccharides based on the electrochemical method.

3-Deoxy-D-manno-Oct-2-ulosonic acid (Kdo)-containing oligosaccharides are a conserved carbohydrate component in lipopolysaccharides (LPSs) of the outer membrane of Gram-negative bacteria, and they are also present in capsular polysaccharides (CPSs) of bacteria and plant cells. The association of the bacterial LPS with the pathophysiology of bacterial infection have long been recognized. Structurepathophysiology studies of bacterial infection need to use pure and homogeneous LPS fragments. Such a requirement can be fulfilled by the synthesis of Kdo glycosides and related Kdooligosaccharide conjugates. This article provides an overview of the glycosylation chemistries of the synthesis of Kdo α-/β-glycosides, oligosaccharides with Kdo units such as LPS core oligosaccharides, and lipid A derivatives.

Current progress on hierarchical supramolecules using boronic acids has been highlighted in this feature article. Boronic acids can participate in “click reactions” with diols and their congeners with dynamic covalent functionality. By comprehensively exploring versatile sequential boronate esterification linkages between plural boronic acid-appended molecules and multiple hydroxyl counterparts, not only versatile supramolecular polymers but also structurally well-defined network nanostructures have been developed. In addition orthogonal interactions such as dative bonds of the boron center with Lewis bases have led to the formation of hierarchical nano/microstructures. Boronate systems have the potential to be used as materials for smart gels, chemosensors, active architectures for electronics, heterogeneous catalysts, chemical-stimulus responsive systems for drug delivery, etc. Here, we fully discuss the feasibility of the structure-directing ability of boronic acids from the standpoint of the generation of new smart materials.

A multicomponent coupling reaction involving in situ generated arynes, phosphine (III) or arsine (V), as well as various acyclic and cyclic activated carbonyl compounds (II), (VII), and (IX) is described.

Bimetallic Pd/Cu and Pd/Ag catalytic systems were used for borylation of propargylic alcohol derivatives. The substrate scope includes even terminal alkynes. The reactions proceed stererospecifically with formal SN2′ pathways to give allenyl boronates. Opening of propargyl epoxides leads to 1,2-diborylated butadienes probably via en allenylboronate intermediate.

N-Heterocyclic carbene (NHC) catalyzed lactonization and lactamization of 2-bromoenals with heterocyclic C–H acids proceeding via the α,β-unsaturated acyl azolium intermediates is reported. The reaction furnished coumarin- or quinolinone-fused lactone/lactam derivatives. In addition, results of the enantioselective version of this reaction using chiral NHC are presented.

The presented procedure gives a broad range of isoxazolidin-5-ones with good enantioselectivities and high yields, with exception of compound (V), from readily available Meldrum′s acid derivatives.

Meldrum′s acid is a useful ketene equivalent in the reaction with nitrones to give isoxazolidin-5-ones, via a domino anionic formal [3 + 2] cycloaddition-decarboxylation process.

The major challenge in carbohydrate synthesis is stereochemical control of glycosidic bond formation. Different glycosylation methods have been developed that are based on the modulation effect of external nucleophiles. This review highlights the development, synthetic application, challenges and outlook of the modulated glycosylation methods.

Double asymmetric induction is employed as a tool to optimize pyrazolidinone derived organocatalysts for the asymmetric iminium ion catalyzed Diels—Alder reaction.

When isoquinoline or quinoline derivatives are used as nucleophiles the reaction proceeds through 1,4-dipolar intermediates yielding spiro-indole-oxazine derivatives.

A new iterative one-pot sequential method for the solution-phase synthesis of oligosaccharides has been devised on the basis of the electrochemical oxidation of a propagating thioglycoside terminus to generate the corresponding triflate, followed by the reaction with a thioglycoside building block having a free hydroxyl group. A practical automated synthesizer was developed for the method and was effectively used for assembling up to six thioglycoside building blocks to synthesize partial structures of poly-β-d-(1–6)-N-acetylglucosamine.

The reversible boronic acid–diol interaction empowers boronic acid receptors' saccharide binding capacities, rendering them a class of lectin mimetic, termed “boronlectins”. Boronic acids follow lectin functions not just in being able to bind saccharides, but in multivalent saccharide binding that enhances both affinity and selectivity. For almost a decade, efforts have been made to achieve and improve selectivity for given saccharide targets, most notably glucose, by using properly positioned boronic acids, offering multivalent interactions. Incorporation of several boronic acid groups into a covalent framework or non-covalent assembly of boronic acid are two general methods used to create such smart sensors, of which the latter resembles lectin oligomerisation that affords multivalent saccharide-binding architectures. In this review, we discuss supramolecular selective sensing of saccharides by using simple boronic acids in their aggregate forms, after a brief survey of the general aspects of boronic acid-based saccharide sensing.

The Passerini reaction of isatins (I) with isocyanides and carboxylic acids affords desired oxindole derivatives such as (IV) and (VI).

A library of 6′-substituted derivatives of Hsp90 inhibitor PU-H71 (I) is synthesized by Suzuki, Stille, Heck, and Sonogashira cross-coupling reactions (45 examples).

β-Glycosyl imidinium triflate is generated from participating thioglycoside donors for disarmed–armed iterative glycosylations and one-pot oligosaccharide synthesis.

Treatment of branched propargylic halides and trifluoroacetates with the reagent (II) at room temperature is found to yield linear allenes.

Small greenish black crystals of K9[V16O38(CN)]·13H2O are prepared by dissolving VO(SO4) in an aqueous solution of KCN followed by slow addition of MeOH (89% yield).

A variety of substrates undergoes SNAr reaction of fluorine with Na2S to produce the corresponding mercaptobenzonitriles.

In contrast to previously reported results, the presented approach leads to the title compound (II) rather than to 2-amino-3-iodonaphthalene.

Highly enantioselective addition of various 1,3-diynes towards aromatic and aliphatic aldehydes is smoothly achieved in the system Et2Zn—(S)-BINOL—Ti(O-iPr)4.

A practically simple three-component Strecker reaction for the asymmetric synthesis of enantiopure α-arylglycines has been developed. Addition of a range of aryl-aldehydes to a solution of sodium cyanide and (S)-1-(4-methoxyphenyl)ethylamine affords highly crystalline (S,S)-α-aminonitriles that are easily obtained in diastereomerically pure form. Heating the resultant (S,S)-α-aminonitriles in 6 M aqueous HCl at reflux resulted in cleavage of their chiral auxiliary fragments and concomitant hydrolysis of their nitrile groups to afford enantiopure (S)-α-arylglycines. The enantiopurities of these (S)-α-arylglycines were determined via derivatization of their corresponding methyl esters with 2-formylphenylboronic acid and (S)-BINOL, followed by 1H NMR spectroscopic analysis of the resultant mixtures of diastereomeric iminoboronate esters.

Different Cu, Ni, and Co salts catalyze the reaction, and CuI is identified as the most effective agent.

During the last decade numerous protocols have been published using the method of ball milling for synthesis all over the field of organic chemistry. However, compared to other methods leaving their marks on the road to sustainable synthesis (e.g. microwave, ultrasound, ionic liquids) chemistry in ball mills is rather underrepresented in the knowledge of organic chemists. Especially, in the last three years the interest in this technique raised continuously, culminating in several high-quality synthetic procedures covering the whole range of organic synthesis. Thus, the present tutorial review will be focused on the highlights using this method of energy transfer and energy dissipation. The central aim is to motivate researchers to take notice of ball mills as chemical reactors, implementing this technique in everyday laboratory use and thus, pave the ground for future activities in this interdisciplinary field of research.

A green fluorescent protein chromophore inspired chemosenor for Zn2+ was designed and synthesized. A Zn2+ specific fluorescence enhancement was observed due to restricted rotation between the 1,10-phenanthroline and imidazolone moieties.

The reaction applies hypervalent iodine reagents as oxidants, proceeds with complete or high (E)-selectivity and tolerates a range of functional groups.

The industrial treatment of spent nuclear fuel is based upon a hydrometallurgical process in nitric acid medium. In order to minimize the volume of radioactive waste it seems interesting to generate the reactive species in situ in such solutions using ultrasonic irradiation without addition of salt-forming reagents. This review summarizes for the first time the versatile sonochemical processes with uranium, neptunium and plutonium in homogeneous nitric acid solutions and heterogeneous systems. The dissolution of refractory solids, ultrasonically driven liquid-liquid extraction and the sonochemical degradation of the volatile products of organic solvent radiolysis issued from PUREX process are considered. Also the guidelines for required further work to ensure successful application of the studied processes at industrial scale are discussed.

In this feature article the use of boronic acids to monitor, identify and isolate analytes within physiological, environmental and industrial scenarios is discussed. Boronic acids recognise diol motifs through boronic ester formation and interact with anions generating boronates, as such they have been exploited in sensing and separation protocols for diol appended molecules such as saccharides and anions alike. Therefore robust molecular sensors with the capacity to detect chosen molecules selectively and signal their presence continues to attract substantial attention, and boronic acids have been exploited with some success to monitor the presence of various analytes. Reversible boronic acid-diol interactions have also been exploited in boron affinity chromatography realising new separation domains through the same binding events. Boronic acid diol and anion interactions pertaining to sensing and separation are surveyed.