Yukinori Yusa

Practical Enantioselective Synthesis of Axially Chiral Biaryl Diphosphonates and Dicarboxylates by Cationic Rhodium(I)/Segphos-Catalyzed Double [2 + 2 + 2] Cycloaddition

A cationic rhodium(I)/Segphos complex catalyzes a [2 + 2 + 2] cycloaddition of internal 1,6-diynes with a phosphonate- or ester-substituted 1,3-butadiyne leading to C(2)-symmetric axially chiral biaryl diphosphonates or dicarboxylates, respectively, in high yields with outstanding ees. The use of a phosphonate- or ester-substituted 1,3-butadiyne as a cycloaddition partner and Segphos as a ligand is crucial for the success of this transformation.

Achiral benzophenone ligand-rhodium complex with chiral diamine activator for high enantiocontrol in asymmetric transfer hydrogenation

The chirality of an achiral benzophenone-based rhodium complex can be controlled by chiral diamines to afford significantly high enantioselectivity in the catalytic asymmetric transfer hydrogenation of ketones (up to 99% ee, 99% yield).

Highly enantioselective spiro cyclization of 1,6-enynes catalyzed by cationic skewphos rhodium(i) complexElectronic supplementary information (ESI) available: typical experimental procedure and spectral data for 1?10. See http://www.rsc.org/suppdata/cc/b3/b310789b/

A cationic rhodium(I) complex having a skewphos ligand is shown to be a highly enantioselective catalyst for asymmetric carbocyclization of 1,6-enynes with tri-substituted olefins to control quaternary stereogenic centers of spiro-rings.