In this paper, the most recent and significant applications of Eosin Y as an organo-photocatalyst will be discussed, focusing the attention on enabling technological aspects in homogeneous photochemical flow reactions, as well as on recent developments in solid-supported catalyst applications for batch synthetic transformations.

1,5‐Benzothiazepine frameworks are highly relevant in medicinal chemistry. Reported catalytic asymmetric approaches to these scaffolds have targeted 2,3‐dihydro‐1,5‐benzothiazepin‐4‐ones but leave the corresponding amines (i.e., 2,3,4,5‐tetrahydro‐1,5‐benzothiazepines) out of reach. Herein, we present the first entry to these important compounds in enantioenriched form. Our approach is based on the catalytic asymmetric sulfa‐Michael addition of 2‐aminothiophenols to trans‐chalcones, followed by intramolecular reductive amination. Both reactions required careful study to solve several challenging issues. The resulting optimized two‐step protocol afforded a range of 2,3,4,5‐tetrahydro‐1,5‐benzothiazepines as single trans diastereomers in moderate to good yields and enantioselectivities.

Deep eutectic solvents (DESs) have gained attention as green and safe as well as economically and environmentally sustainable alternative to the traditional organic solvents. Here, we report the combination of an atom-economic, very convenient and inexpensive reagent, such as BH3NH3, with bio-based eutectic mixtures as biorenewable solvents in the synthesis of nitroalkanes, valuable precursors of amines. A variety of nitrostyrenes and alkyl-substituted nitroalkenes, including α- and β-substituted nitroolefins, were chemoselectively reduced to the nitroalkanes, with an atom economy-oriented, simple and convenient experimental procedure. A reliable and easily reproducible protocol to isolate the product without the use of any organic solvent was established, and the recyclability of the DES mixture was successfully investigated.

Starting from commercially available ketones, a reproducible and reliable strategy for the synthesis of tetrasubstituted nitroalkenes was successfully developed, using a two-step procedure; the HWE olefination of the ketone to form the corresponding α,β-unsaturated esters is followed by a nitration reaction to introduce the nitro group in the α position of the ester group. The enantioselective organocatalytic reduction of these compounds has also been preliminarily studied, to access the functionalized enantioenriched nitroalkanes, which are useful starting materials for further synthetic elaborations. The absolute configuration of the reduction product was established by chemical correlation of the chiral nitroalkane with a known product; preliminary DFT calculations were also conducted to rationalize the stereochemical outcome of the organocatalytic enantioselective reduction.

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