New chiral bis(oxazolinyl)bipyridine ligand (bipymox): Enantioselection in the asymmetric hydrosilylation of ketones

Chiral 2,2‘-Bipyridines, 1,10-Phenanthrolines, and 2,2‘:6‘,2‘ ‘-Terpyridines: Syntheses and Applications in Asymmetric Homogeneous Catalysis

“…49 Although bipymox could coordinate in a terdentate fashion, the bidentate bipymox-rhodium complex 174 was formed preferentially.…”

Novel Chiral Oxazoline Ligands for Potential Charge-Transfer Effects in the Rh(I)-Catalysed Enantioselective Hydrosilylation

“…Condensation of 14 with 2 equivalents of (R)-α-phenylglycinol yielded 15 as the first example of a chiral C 2 -symmetrical 4,4Ј-bipyridine derivative, which is able to coordinate to two metal centres. The corresponding 2,2Ј-bipyridine-bisoxazoline was synthesised by Nishiyama et al [32] . In the 1 H NMR spectra 15 and its mono-oxazoline counterpart 3d display nearly identical chemical shifts for the oxazoline protons and the ABX system of the pyridine ring.…”

Ionic and Organometallic‐Catalyzed Organosilane Reductions

“…Chiral bis(oxazolinyl)bipyridine (bipymox) ligands in combination with rhodium(II) chloride, AgBF 4 , and diphenylsilane reduce prochiral ketones in good to excellent yields and 24 to 90% ee. 572 The complexes formed with rhodium(I) are not as effective and some silyl enol ethers are formed from enolizable ketones. Rhodium(I) complexes with (+)-or (−)-DIOP [(2,2-dimethyl-1,3-dioxolane-4,5diyl)bis(methylene)bis(diphenylphosphine)] ligands catalyze the diphenylsilane reduction of 17-keto steroids with only a moderate enhancement for the α-hydroxy steroid over the results obtained from the corresponding achiral reductions.…”