A facile method for the synthesis of unsaturated organoboron compounds by hydroboration of terminal and internal alkynes in supercritical (sc) CO2 has been presented for the first time. The reactions performed in scCO2 in the presence of Ru catalysts (selectivity, productivity) are compared with those in a traditionally used solvent or without it. Moreover, the catalytic systems based on the application of scCO2 have been successfully tested for the processes under repetitive batch conditions. This strategy permitted us to obtain boryl‐substituted olefins with high yields and selectivities up to the 16th catalytic cycle if using Ru(CO)Cl(H)(PPh3)3 as a catalyst. The process applied the self‐dosing catalyst, which is gradually released to the reaction mixture under supercritical conditions in the individual batch. Such an approach has a positive impact on process sustainability and economy.

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The efficient one-pot halofluorination of a β-enaminophosphonate/β-iminophosphonate tautomeric mixture resulting in α,α-halofluorinated β-iminophosphonates is reported. Subsequent imine reduction gave the corresponding β-aminophosphonates as a racemic mixture or with high diastereoselectivity. The proposed protocol is the first example of a synthesis of N-inactivated aziridines substituted by a fluorine and phosphonate moiety on the same carbon atom. Based on spectroscopic and theoretical studies, we determined the cis/trans geometry of the resulting fluorinated aziridine-2-phosphonate. Our procedure, involving the reduction of cis/trans-fluoroaziridine mixture 24, allows us to isolate chiral trans-aziridines 24 as well as cis-aziridines 27 that do not contain a fluorine atom. We also investigated the influence of the fluorine atom on the reactivity of aziridine through an acid-catalyzed regioselective ring-opening reaction. The results of DFT calculations, at the PCM/ωB97x-D/def2-TZVPD level of theory, are in good agreement with the experiments. The transition states of the SN2 intramolecular cyclization of vicinal haloamines have been modeled.

Recently, the development of suitable synthetic methodologies using metal-based catalysts for coupling reactions, oxidation or reduction as well as epoxidation have become topics of great interest. This review article surveys recent achievements in the application of such catalysts as templated porous-metal phosphonates, layered-metal phosphonates, and phosphonate-based metal-organic frameworks (MOFs) in organic syntheses. Additionally, the preparation of various catalysts with defined structure and morphology from organic phosphonate precursors are presented. The versatile properties of phosphonate-containing catalysts offer new and efficient applications in classical as well as modern organic reactions.

The Cover Feature shows a figurative synthesis of alkenyl boronates via hydroboration of alkynes with boranes in the presence of a Ru−H catalyst conducted in supercritical CO2 (scCO2) under repetitive batch mode. In their Full Paper, J. Szyling et al. describe the application of scCO2 as a solvent and extractant in the repetitive batch hydroboration, using a self‐dosing Ru−H catalyst, which is gradually released to the reaction mixture under supercritical conditions. The strategy is a sustainable and green manner to obtain boryl‐substituted olefins (easily extracted in scCO2) with high yields and selectivities up to the 16th catalytic cycle. More information can be found in the Full Paper by J. Szyling et al. on page 531 in Issue 3, 2018 (DOI: 10.1002/cctc.201701318).