I agree Our site saves small pieces of text information (cookies) on your device in order to deliver better content and for statistical purposes. You can disable the usage of cookies by changing the settings of your browser. By browsing our website without changing the browser settings you grant us permission to store that information on your device.
(S)-(-)-alpha,alpha-Diphenylprolinol is used to prepare the corresponding oxazaborolidines for the borane-mediated asymmetric reduction of ketones.
Precursor of Corey, Bakshi and Shibata's oxazaborolidine derivatives (CBS catalysts) for enantioselective reduction of prochiral ketones: J. Am. Chem. Soc., 109, 5551 (1987). Ketones are not reduced rapidly by either borane-THF or the oxazaborolidine alone but together they form a complex which reduces ketones rapidly and stereoselectively, permitting reduction with very high ee in the presence of a catalytic amount of the oxazaborolidine: J. Am. Chem. Soc., 109, 7925 (1987).
For use in conjunction with borane generated in situ using NaBH4 and iodine, see: Tetrahedron, 50, 6411 (1994). For an optimized in situ procedure for generation and use of the oxazaborolidine from BMS, see: Tetrahedron: Asymmetry, 7, 3147 (1996). In a comparison with other oxazaborolidine precursors, diphenylprolinol gave the best results (same ref.). For in situ generation of an asymmetric reduction system using trimethyl borate and BMS, see: Synlett, 273 (1997). For the generation and use of the phenyl oxazaborolidine, using Benzeneboronic acid, A14257, see: Tetrahedron Lett., 31, 7415 (1990); 32, 7175 (1991); J. Org. Chem., 57, 7115 (1992). For a detailed comparative study of various alkyl- and aryl-substituted borolidines, see: J. Org. Chem., 56, 763 (1991). For a process for the in situ formation of butyl oxazaborolidines using 1-Butylboronic acid, A13725, see: Tetrahedron Lett., 33, 4141 (1992). For use for the catalytic enantioselective synthesis of chiral monosubstituted oxiranes, see: Tetrahedron Lett., 34, 5227 (1993).
For reviews of oxazaborolidines as enantioselective catalysts, see: Angew. Chem. Int. Ed., 31, 729 (1992); 37, 1986 (1998); Tetrahedron: Asymmetry, 3, 1475 (1992). For reviews of the asymmetric reduction of ketones, see: Synthesis, 605 (1992); Chem. Ind. (London), 552 (1994).
See also the preformed catalyst (S)-2-Methyl-CBS-oxazaborolidine, L14583, and (S)-2-Methyl-CBS-oxazaborolidine monohydrate, L09219.
Hazard Statements: H315-H319-H335
Causes skin irritation. Causes serious eye irritation. May cause respiratory irritation.
Precautionary Statements: P261-P280a-P305+P351+P338-P304+P340-P405-P501a
Avoid breathing dust/fume/gas/mist/vapours/spray. Wear protective gloves and eye/face protection. IF IN EYES: Rinse cautiously with water for several minutes. Remove contact lenses, if present and easy to do. Continue rinsing. IF INHALED: Remove to fresh air and keep at rest in a position comfortable for breathing. Store locked up. Dispose of contents/container in accordance with local/regional/national/international regulations.