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A combined computational and experimental approach allowed us to develop overall the most selective catalyst for the direct hydrogenation of N‐methyl, N‐alkyl and N‐aryl imines described to date. Iridium catalysts with a cyclometallated cyclic imide group provide selectivity of up to 99 % enantiomeric excess. Computational studies show that the selectivity results from the combined effect of H‐bonding of the imide C=O with the substrate iminium ion and a stabilizing π–π interaction with the cyclometallated ligand. The cyclometallated ligand thus exhibits a unique mode of action, serving as a template for the H‐bond directed approach of the substrate which results in enhanced selectivity. The catalyst (2) has been synthesized and isolated as a crystalline air‐stable solid. X‐ray analysis of 2 confirmed the structure of the catalyst and the correct position of the imide C=O groups to engage in an H‐bond with the substrate. 19F NMR real‐time monitoring showed the hydrogenation of N‐methyl imines catalyzed by 2 is very fast, with a TOF of approx. 3500 h−1. [ABSTRACT FROM AUTHOR]

A one‐pot Pd‐catalyzed tandem process to prepare (2‐arylallyl) aryl sulfones has been developed. This strategy is based on the modular assembly of a boronic acid, a sodium sulfinate and 2‐bromoallyl acetate. The reaction is completely regioselective towards the terminal alkene, yielding (2‐arylallyl) aryl (or alkyl) sulfones with yields ranging from 56 to 93%. Control experiments together with DFT calculations allowed to propose a plausible reaction mechanism of the tandem reaction. The usefulness of this methodology has been demonstrated with the formal synthesis of the marketed drug Apremilast and of several natural products by asymmetric hydrogenation. Using the commercially available UbaPHOX iridium complex, chiral β‐methyl sulfones with up to 98% ee were obtained [ABSTRACT FROM AUTHOR]

This study details an aluminum‐catalyzed regioselective isomerization of 2,2‐disubstituted oxetanes to yield homoallylic alcohols. The reaction takes place in toluene at 40 °C, employing 1 mol % of Al(C6F5)3 as catalyst. This catalytic system shows a wide substrate scope (12 examples). The optimized conditions are especially useful for electron‐rich aryl oxetanes, completely suppressing the formation of allyl isomers and reducing the amount of the dimer by‐product. The synthetic applicability of the reported methodology is demonstrated by the enantioselective formal synthesis of curcuquinone and the σ1 receptor agonist RC‐33. [ABSTRACT FROM AUTHOR]

Synthesis and use of Pulegone-derived bidentate P,S ligands PuPHOS and CyPuPHOS in the intermolecular Pauson-Khand reaction (PKR) were described. Intermolecular PKR of trimethylsilylacetylene complex occurred in a completely stereospecific fashion to yield optically enriched cyclopentenone.

Research has been conducted on the enantiopure 10-(R-thio)-2-exo-bornanethiols. The procedure for the preparation of these compounds from (1S)-camphor-10-thiol has been developed and the results demonstrate that the ethynyl derivatives of these thiols produce excellent diastereoselectivities in Pauson-Khand reactions with norbornene and norbornadiene.

A synthetically useful catalytic process for the reduction of five- and six-membered lactones using polymethylhydrosiloxane as the stoichiometric reductant was designed. Two strategies were developed such that straightforward activation of the precatalyst produces an efficient catalyst for the hydrosilylation of lactones. A simple aqueous workup frees the lactol products, which can be purified and isolated in good to excellent yields.

A simple and convenient methodology for the preparation of optically pure 2-amino-2-aryl-1,1-diphenylethanols is presented. Removal of allyl protecting group provided the free 1,2-amino alcohols in enantiomerically pure form.