A study toward understanding the role of a phosphorus stereogenic center in (5S)-1,3-diaza-2-phospha-2-oxo-3-phenylbicyclo(3.3.0)octane derivatives as catalysts in the borane-mediated asymmetric reduction of prochiral ketones

Direct 1,1-Bisphosphonation of Isocyanides: Atom- and Step-Economical Access to Bisphosphinoylaminomethanes

An atom- and step-economical strategy for the synthesis of bisphosphinoylaminomethanes is reported. This metal-free bisphosphinylation reaction proceeded smoothly through a base-mediated direct 1,1-bisphosphonation of phosphine oxides and isocyanides under mild conditions. The present method offers a facile, efficient, and general approach to a broad range of bisphosphinoylaminomethane derivatives in moderate to good yields.

Applications and stereoselective syntheses of P-chirogenic phosphorus compounds

This review reports the best stereoselective or asymmetric syntheses, the most efficient P*-building blocks and functionalisation of P-chirogenic compounds, in the light of chiral phosphorus compound applications.

Synthesis of a new C(2)-symmetric chiral catalyst and its application in the catalytic asymmetric borane reduction of prochiral ketones

A new C(2)-symmetric chiral catalyst 3,5-bis[(2S)-(hydroxy-diphenylmethyl)- pyrrolidin-1-ylmethyl]-1,3,4-oxadiazole was successfully synthesized by the reaction of 2,5-dichloromethyl-1,3,4-oxadiazole with (S)-alpha,alpha-diphenyl-2-pyrrolidinemethanol, and applied to the catalytic asymmetric reduction of prochiral ketones with borane. When the catalyst loading was 1 mol %, enantiomeric excesses of up to 86.8% and 94.5% were observed in reduction of aromatic and alpha-halo ketones, respectively.

Increased Enantioselectivity and Remarkable Acceleration of Lipase-Catalyzed Transesterification by Using an Imidazolium PEG–Alkyl Sulfate Ionic Liquid

Several types of imidazolium salt ionic liquids were prepared derived from poly(oxyethylene)alkyl sulfate and used as an additive or coating material for lipase-catalyzed transesterification in an organic solvent. A remarkably increased enantioselectivity was obtained when the salt was added at 3-10 mol % versus substrate in the Burkholderia cepacia lipase (lipase PS-C)-catalyzed transesterification of 1-phenylethanol by using vinyl acetate in diisopropyl ether or a hexane solvent system. In particular, a remarkable acceleration was accomplished by the ionic liquid coating with lipase PS in an iPr(2)O solvent system while maintaining excellent enantioselectivity; it reached approximately 500- to 1000-fold acceleration for some substrates with excellent enantioselectivity. A similar acceleration was also observed for IL 1-coated Candida rugosa lipase. MALDI-TOF mass spectrometry experiments of the ionic-liquid-coated lipase PS suggest that ionic liquid binds with lipase protein.