As process chemistry is rarely included in university curricula, experts from Swiss companies pass on their experience to students at various levels.

The idea beyond this column is to point out the difficulties that students or pupils often have when solving problems that require handling units. These include the use of the proper unit for the corresponding physical quantity during the calculation, analysis of the units and providing the result as a numerical value with a correct unit. A wish to join the efforts of all teachers to solve this problem is also expressed.

The typically planar amide when incorporated into bicyclic systems can undergo a significant distortion from planarity resulting in physical properties and reactivity that deviate from classical amide behaviour. Herein, we report a succinct protocol that utilises potassium permanganate to selectively α-oxygenate the benzylic position of ethano-Tröger's base derivatives to yield a new class of twisted bisamides. Additionally, we report the first synthesis of an ethano-Tröger's base derivative bearing substituents in the positions ortho to the nitrogen atoms.

The potential of phase-transfer catalysis in the synthesis of Troger's base analogues via a double aza-Michael addition has been evaluated. It has been observed that no external base is required and PTC may significantly enhance the efficiency of the process or control the selectivity.

Introduction of oxygen and nitrogen into organic molecules is one of the fundamental strategies for their functionalization. Traditional approaches rely on the formation of an activated intermediate, which is then modified in a subsequent step. Here we report a simple direct oxidative alpha-acetoxylation and azidation of alpha-C-H bonds in Troger's base analogues promoted by N-bromosuccinimide (NBS) and palladium(II) acetate [Pd(OAc)(2)] under mild conditions. This approach is pivotal on NBS oxidizing the carbon atoms next to the nitrogen atoms in the presence of Pd(OAc) 2 followed by a reaction with oxygen- or nitrogen-centred nucleophiles such as KOAc or NaN3 to yield either the mono-and bisacetoxylated or azidated Troger's base derivatives in a stereo- and chemoselective manner. The obtained products can be efficiently modified to access synthetically meaningful structures.

Methylation of 2,8-dimethyl-6H,12H-5,11-ethanodibenzo[b,f][1,5]-diazocine (ethano-Tröger's base) with methyl iodide followed by ion metathesis and fluorination with N-fluoro-2,3,4,5,6-pentachloropyridinium triflate affords a new electrophilic N-F reagent, that is more reactive than Selectfluor. 2D (19)F-(15)N HMQC experiments provide (1)JNF coupling constants which are diagnostic for the N-F functional group.

Further development of the chemistry and applications of chiral compounds that possess configurationally stable stereogenic nitrogen atoms is hampered by the lack of efficient strategies to access such compounds in an enantiomerically pure form. Esters of propiolic acid and chiral alcohols were evaluated as cheap and readily available Michael acceptors in a diastereoselective synthesis of N-stereogenic compounds by means of a double aza-Michael conjugate addition. Diastereomeric ratios of up to 74: 26 and high yields were achieved with (-)-menthyl propiolate as a substrate. Furthermore, a detailed mechanistic investigation was undertaken to shed some light on the course of this domino transformation. Kinetic studies revealed that the protic-solvent additive acts as a Bronsted acid and activates the ester toward the initial attack of the tetrahydrodiazocine partner. Conversely, acidic conditions proved unfavorable during the final cyclization step that provides the product.

A new method for the activation of the non-benzylic α-C–H bonds in tertiary diamines has been developed. The protocol relies on an N-bromosuccinimide (NBS)-mediated oxidation of carbon atoms next to the nitrogen atoms in the presence of a catalytic amount of Pd(OAc)2 followed by an intermolecular reaction with oxygen- or nitrogen-centered nucleophiles. Mechanistic studies hint towards a radical intermediate, which can be further oxidized to an olefin or a non-classical carbocation. Stable α-oxygen- or α-nitrogen-substituted bicyclic tertiary amines are thus efficiently accessed under mild conditions.

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

A novel approach towards the asymmetric synthesis of N-stereogenic molecules via double aza-Michael addition was developed. The diastereomeric ratio can be increased by a thermodynamically controlled isomerization mechanism. Simple separation and functionalization of the products afford N-stereogenic compounds in high enantiomeric purity.

This report deals with the rapid functionalization of the 4,4-difluoro-4-bora-3a,4a-diaza-s-indacene (BODIPY) scaffold by means of electrophilic trifluoromethylation. Subjecting dye 2 to the disclosed protocol led to the successful isolation of 3-trifluoromethylated derivative 9. Subsequent comparison of structural and electronic properties allowed for the characterization of changes imparted by the CF3 group. A diminution in the quantum yield [ΦF(2)MeOH = 0.15, ΦF(9)THF = 0.024] was accompanied by a larger Stokes shift [ΔS(2)MeOH = 12 nm, ΔS(9)THF = 54 nm], whereas the molar extinction coefficient at the global absorbance maximum remained largely unaffected [ϵ(2)MeOH = 40 × 103 M–1 cm–1, ϵ(9)THF = 30 × 103 M–1 cm–1].

AbstractA rare example of stereoselective synthesis of molecules possessing configurationally stable chirogenic nitrogen atoms is developed.

The preparation, full characterization and determination of the absolute configuration of diastereomerically pure disulfoxide derivatives of Tröger's base are described. A sulfinyl-lithium exchange followed by the reaction with electrophiles affords synthetically meaningful amounts of enantiomerically pure 4,10-disubstituted Tröger's base analogues without any erosion of the stereogenic information at the nitrogen centers.

followed by an intense discussion.The chatter then continued at a get together where all the participants could enjoy a nice glass of wine.As usual, debates ended at the hotel bar.The moderation of the Monday morning session was in the hands of Karl-Heinz Altmann (ETH Zürich).The first speaker Christophe Copéret, also from ETH, explained how one can control the chemistry on oxide supports to generate well-defined supported catalysts, thus bridging the gap between homogeneous and heterogeneous catalysis.Applying molecular approaches and spectroscopies, he explained how his research group clarified the structure of some relevant industrial catalysts, e.g. for metathesis and polymerization, which have been used for decades, and even how it was possible to design novel well-defined catalysts with superior performance.He also demonstrated how new techniques such as Dynamic Nuclear Polarization Surface Enhanced NMR spectroscopy could help characterize surface species at the atomic level in a short time (decreasing experimental times by several 10'000).He finally described that this molecular approach was applicable not only to catalyst design and preparation, but also to the development of imaging technologies.

*Correspondence: Dr. m. Creusa; Dr. J. Cvengrošb; Dr. a. K. Lawrencec aLaboratory of molecular Evolution, Department of Chemistry, University of Basel, Spitalstrasse 51, Ch-4056 Basel; E-mail: marc.creus@unibas.ch bETh Zürich, Laboratory of inorganic Chemistry hCi h 230, Wolfgang-Pauli-Str. 10, Ch-8093 Zürich, E-mail: cvengros@inorg.chem.ethz.ch cSwiss academy of Sciences (SCNaT), Platform Chemistry, Schwarztorstrasse 9, Ch-3007 Bern, E-mail: chemistry@scnat.ch

A library of bis(phosphane) ligands based on the 2,8-substituted Troger's base scaffold was synthesized through an efficient two-step protocol by starting from a commercially available aniline. The new ligands proved their efficiency in palladium-catalyzed Suzuki-Miyaura cross-coupling reactions and Buchwald-Hartwig aminations of aryl chlorides and bromides.

A library of novel C2-symmetric P,N ligands based on a Tröger’s base backbone was prepared via a concise two-step synthesis starting from a commercially available aniline derivative. X-ray crystallography and 31P NMR studies confirm that a single ligand molecule can accommodate two palladium atoms via coordination to nitrogen and phosphorus. Preliminary results proved the synthetic potential of this species in Suzuki cross-coupling reactions of aryl bromides with arylboronic acids.

In this paper six new or innovated procedures of fatty acids methyl esters (FAME) preparation from natural triacylglycerols (TAG) with higher acidity are described. The extraction of soaps of free fatty acids (FFA) by a polar solvent such as glycerol (G), but primarily by the G-phase originating from own FAME production, is a simple procedure applicable mainly in small-scale production plants. The effective TAG deacidification is obtained also using FFA vacuum distillation in wiped film evaporators. Preliminary acidcatalyzed FFA esterification with methanol (MeOH) performed before alkali-catalyzed TAG transesterification to FAME allows a simple separation of reaction water, excess of MeOH, and acidic catalyst at appropriate reactant ratios. During FFA esterification at temperatures over 110 °C, ambient pressure and at continuous MeOH feeding to the reaction mixture, advantageous nonequilibrium conditions for effective mass and heat transfer are created. Ethanolamines, used in TAG degumming for technical application, form separable adducts with water and FFA. At high-temperature FFA esterification with G in acid oils, acidic functional groups are blocked. The mentioned procedures are technically feasible and allow decreasing TAG acidity down to 1.0 mg KOH/g or less. Conversion of acyl glycerols to FAME complies with the standard EN 14 214.