Selective separation of enantiomers is a substantial challenge for the pharmaceutical industry. Chromatography on chiral stationary phases is the standard method, but at a very high cost for industrial-scale purification due to the high cost of the chiral stationary phases. Typically, these materials are poorly robust, expensive to manufacture, and often too specific for a single desired substrate, lacking desirable versatility across different chiral analytes. Here, we disclose a porous, robust homochiral metalorganic framework (MOF), TAMOF-1, built from copper(II) and an affordable linker prepared from natural L-histidine. TAMOF-1 has shown to be able to separate a variety of model racemic mixtures, including drugs, in a wide range of solvents of different polarity, outperforming several commercial chiral columns for HPLC separations. Although not exploited in the present article, it is worthy to mention that the preparation of this new material is scalable to the multikilogram scale, opening unprecedented possibilities for low-energy chiral separation at the industrial scale.

Iridium(I) complexes of enantiomerically pure phosphine-phosphite ligands ([Ir(Cl)(cod)(P-OP)]) efficiently catalyze the enantioselective hydrogenation of diverse C═N-containing heterocyclic compounds (benzoxazines, benzoxazinones, benzothiazinones, and quinoxalinones; 25 examples, up to 99% ee). A substrate-to-catalyst ratio as high as 2000:1 was reached.

Different methods for transforming N-heteroarenes into more reactive derivatives for catalytic asymmetric hydrogenation are highlighted. The first strategy consists of facilitating hydrogenation by the formation of positively charged derivatives of the heteroarene. Catalyst deactivation processes arising upon binding of the substrate to the metal center can thus be prevented and, additionally, hydrogenation of positively charged heteroarenes may also be more favored than that of their neutral analogues. The second strategy is based onScheme 4. Chelation assistance during asymmetric hydrogenation of six-membered heteroarenes.(eight examples), although in some cases small quantities of partially hydrogenated compounds were detected. Enantioselectivities were generally high (up to 90 %).www.eurjoc.org

Herein an overview of reductive catalytic enantioselective desymmetrisation of achiral or meso compounds is provided. The most efficient reductive desymmetrisations described in the literature, which involve the reduction of C=O, C=N, C=C and C-halogen bonds, or reductive ring-opening, are summarised. The structural diversity of the valuable highly enantioenriched intermediates prepared by reductive desymmetrisation is highlighted.