Remote Enantioselective Epoxidation Reactions Catalyzed by Chiral Iron Porphyrin Complexes with a Hydrogen-Bonding Site

Iron porphyrin complexes, which were linked via a para-phenylethynyl group to a chiral scaffold with a lactam binding site, were probed as catalysts in the enantioselective epoxidation of 4-(ω-alkenyl)-quinolones. It was found that the 3-butenyl group in the substrate accounts for the highest enantioselectivity (up to 44% ee) and the absolute configuration of an oxirane product was elucidated by electron diffraction. A two-point hydrogen bond of the substrate to the catalyst is likely responsible for enantioface differentiation at a remote position. The study shows chirality transfer to be possible via four nonstereogenic carbon atoms between the binding site of the substrate and its reactive C=C double bond.

A Simplified Protocol for Large-Scale Preparation of 4CzIPN and 3DPA2FBN

Just in the past few years, the application of 4CzIPN as a photocatalyst in photochemistry has been dramatically increased with its unique properties. In the literature, a variety of protocols for the synthesis of 4CzIPN have been reported. However, a practical process for the preparation of 4CzIPN with consistent quality on large scale is not available, but highly desirable to enable the robust application of this photocatalysis in industry. Herein, we detailed a practical and simple column-free chemical process amenable for the large-scale production of 4CzIPN with high quality in 91% yield. Current process was demonstrated on large scale. The similar process protocol was applicable and demonstrated for the synthesis of 3DPA2FBN on large scale.