A copper catalyst with a chiral pyridine-2,6-bisoxazoline (pybox) ligand was used to convert a variety of propargylic esters with different side chains (R=Ar, Bn, alkyl) into their amine counterparts in very high yields and with good enantioselectivities (up to 90% enantiomeric excess (ee)). Different amine nucleophiles were applied in the reactions and the highest enantioselectivities were obtained for aniline and its analogues. Interestingly, some carbon nucleophiles could also be used and with indoles excellent ee values were obtained (up to 98% ee). The versatility of the propargylic amines obtained was demonstrated by their further elaboration to formal total syntheses of the antibiotic (+)-anisomycin and the cytokine modulator (-)-cytoxazone.

A small library of 17 modular and easily accessible phenol-derived chiral phosphine-phosphite ligands was evaluated in the asymmetric Rh-catalyzed hydroformylation of styrene. It was found that the stereochemical outcome of the reaction is highly dependent on the chiral phosphite moiety and the substituents on the phenolic backbone. Among the ligands studied, Taddol-based ligands of type 10 bearing bulky substituents in ortho-position to the phosphite performed best, with enantioselectivities of up to 85% ee and regioselectivities of g98:2. High-pressure NMR of the active catalyst [HRh(P-P)(CO) 2 ] (P-P = 10h) revealed an equatorial-apical coordination of the ligand at rhodium. Temperature dependency of the coupling constants observed during the experiment indicates equilibrium between the two equatorial-apical isomers, with the isomer in which the phosphite occupies the equatorial position being the dominant species.

A high throughput catalyst screening is presented employing an evolutionary approach. The method comprises the optimization of initial leads by subjecting the catalysts to iterative rounds of optimization, including structural elaboration of the ligands by creating new focused libraries. Highly modular supramolecular ligands, robotized synthesis combined by high throughput experimentation creates a platform for fast catalyst development. An illustrative example for the asymmetric hydrogenation of cyclic 2,3,3-trimethyl-3H-indole using iridium catalysts is presented. The kinetic investigation of the best catalyst yields an unusual second order in iridium, first order in hydrogen and zeroth order in substrate. Under optimized reaction conditions a TOF of 100 mol mol À1 h À1 with 96% ee could be obtained with the best catalyst. A full catalyst screening and kinetic study was conducted within a three-week time-frame.

Rational design of ligands for regioselective transformations is one of the long pursuing targets in the field of transition metal catalysis. In the current contribution, we report OrthoDIMphos (L2), a ligand that was designed for regioselective hydroformylation of 3‐butenoic acid and its derivatives. The previously reported ParaDIMphos (L1) based hydroformylation catalyst was very selectively producing the linear aldehyde when substrates were bound in its pocket via hydrogen bonding. However, the distance between the binding site and the rhodium center was too large to also address 3‐butenoic acid and its derivatives. We therefore designed OrthoDIMphos (L2) as new ligand which has a shorter distance between the DIM‐receptor and the catalytic center. The OrthoDIMphos (L2) based catalyst displays high regioselectivity in the hydroformylation of 3‐butenoic acid and challenging internal alkene analogue (l/b up to 84, TON up to 630), which cannot be achieved with the ParaDIMphos (L1) catalyst. Detailed studies show that the OrthoDIMphos (L2) based catalyst forms a dimeric structure, in which the two ligands coordinate to two different rhodium metals. Substrate binding to the DIM‐receptor is required to break up the dimeric structure, and as only the monomeric analogue is a selective catalyst, the outcome of the reaction is dependent on substrate concentration used in catalysis.

Efficient catalysts are crucial for the sustainable generation of fuel by splitting water. A versatile screening protocol would simplify the identification of novel and better catalysts by using high throughput experimentation. Herein, such a screening approach for the identification of molecular catalysts for chemical oxidation of water is reported, which is based on oxygen-sensitive fluorescence quenching using an OxoDish. More than 200 reactions were performed revealing several catalysts, for example, a dinuclear Fe complex that produced oxygen under the used reaction conditions. Clark electrode measurements confirmed a similar rate in oxygen evolution, making the developed parallel screening approach a robust and versatile tool to screen for molecular water oxidation catalysts using chemical oxidants under acidic and neutral conditions.

A bidentate ligand with an integrated anion receptor forms dimeric rhodium complexes that become monomeric upon binding acetate guest, which is the basis for effector responsive hydroformylation catalysis.

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Invited for this month’s cover is the group of Joost Reek at the University of Amsterdam. The image shows a screening approach for the identification of molecular catalysts for chemical oxidation of water, which is based on oxygen‐sensitive fluorescence‐quenching using an OxoDish. The Full Paper itself is available at .