Discovery of a novel analogue of FR901533 and the corresponding biosynthetic gene cluster from Streptosporangium roseum No. 79089

et al. 2023

J. Org. Chem.

A photocatalyst- and additive-free visible-light-induced 6π-photocyclization of ortho-biaryl-appended β-ketoesters has been developed. Upon irradiation with visible light, substrates undergo 6-endo-trig cyclization/1,5-H shift to 9,10-dihydrophenanthren-9-ols with high efficiency and selectivity. The reaction proceeds via conrotatory ring closure followed by a suprafacial 1,5-hydrogen shift leading to the observed single trans-fused products. Preliminary mechanistic studies reveal the feasibility of both 1,5-H shift and intersystem crossing of the diradical intermediate.

Section: Introductionmentioning

confidence: 99%

Visible-Light-Promoted 6π Photocyclization of ortho-Biaryl-Appended β-Ketoesters

et al. 2023

J. Org. Chem.

Ruthenium‐Catalyzed Enantioselective Hydrogenation of 9‐Phenanthrols

Fan

et al. 2022

Angewandte Chemie

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 rutheniumcatalyzed 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 9,10dihydrophenanthren-9-ols with up to 98 % yield and > 99 % ee. The hydrogenation pathway includes basepromoted tautomerization of 9-phenanthrols and Rucatalyzed asymmetric hydrogenation of the in situ generated unstable keto tautomers.

Ruthenium‐Catalyzed Enantioselective Hydrogenation of 9‐Phenanthrols

Fan

et al. 2022

Angew Chem Int Ed

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.