Search

Comprehensive Summary: Chiral ruthenium‐catalyzed enantioselective hydrogenation of tetrapyridine‐type N‐heteroarenes was firstly developed. The partial reduction of adjacent tetraheteroaromatic substrates proceeded smoothly in the presence of phosphine‐free chiral cationic ruthenium diamine complexes, affording unprecedented high reactivity, enantioselecitivity and diastereoselectivity (up to 93% yield, >99% ee and 92 : 8 dr). The potential application of chiral tetradentate pyridine‐amine products as chiral ligands has been demonstrated in the Cu‐catalyzed asymmetric Friedel–Crafts alkylation reaction between indoles and nitroalkenes. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: Chiral ruthenium‐catalyzed enantioselective hydrogenation of tetrapyridine‐type N‐heteroarenes was firstly developed. The partial reduction of adjacent tetraheteroaromatic substrates proceeded smoothly in the presence of phosphine‐free chiral cationic ruthenium diamine complexes, affording unprecedented high reactivity, enantioselecitivity and diastereoselectivity (up to 93% yield, >99% ee and 92 : 8 dr). The potential application of chiral tetradentate pyridine‐amine products as chiral ligands has been demonstrated in the Cu‐catalyzed asymmetric Friedel–Crafts alkylation reaction between indoles and nitroalkenes. [ABSTRACT FROM AUTHOR]

The enantioselective hydrogenation of arenols to corresponding chiral cyclic alcohols remains a challenge because of their aromaticity and the difficulty in controlling the regio‐, chemo‐, and stereoselectivity. In this work, the first highly efficient ruthenium‐catalyzed enantioselective hydrogenation of 9‐phenanthrols has been successfully realized under mild conditions via trapping the unstable keto tautomers. The method provides a facile access to a range of chiral 9,10‐dihydrophenanthren‐9‐ols with up to 98 % yield and >99 % ee. The hydrogenation pathway includes base‐promoted tautomerization of 9‐phenanthrols and Ru‐catalyzed asymmetric hydrogenation of the in situ generated unstable keto tautomers. [ABSTRACT FROM AUTHOR]