Production of chiral non-racemic 2-halopropionic acid or salt thereof
AssigneeAlbemarle Corporation
InventorsEdward G. Samsel, Christi R. Bedell
Life of this patent
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Abstract
It has been discovered that it is possible to produce enantioselectively, a chiral 2-haloalkanoic acid or salt thereof, by subjecting a 2-halo-α,β-alkenoic acid or salt, e.g., a 2-haloacrylic acid or salt, to asymmetric hydrogenation in the presence of an enantiometrically-enriched (BINAP)Ru(II) catalyst. In contrast to asymmetric hydrogenation of olefinic compounds having an electron rich, electropositive substituent in the 2-position, the substituent in the 2-position is an electronegative, electron-withdrawing halide substituent. The reaction is accelerated by inclusion of an alkali metal halide or quaternary ammonium halide in the reaction mixture.
Claims36
A process which comprises subjecting at least one 2-halo-α,β-alkenoic acid and/or salt thereof, to asymmetric hydrogenation in a liquid phase reaction mixture and in the presence of a catalytic system formed by the inclusion in the reaction mixture of (a) at least one enantiomerically-enriched (BINAP)Ru(II) catalyst and (b) at least one alkali metal halide, ammonium halide, or quaternary ammonium halide in which the halide is derived from a halogen atom of atomic number greater than 9, such that at least one chiral 2-haloalkanoic acid and/or salt thereof is enantioselectively produced.
A process which comprises subjecting at least one 2-haloacrylic acid and/or salt thereof, to asymmetric hydrogenation in at least one liquid alcohol reaction medium with which at least one alkali metal base is mixed, and in the presence of a catalyst that is:
- 1) at least one enantiomerically-enriched (BINAP)Ru(II) catalyst;
- 2) catalytic species, if any, formed by the inclusion of at least one enantiomerically-enriched (BINAP)Ru(II) catalyst as a component used in making up the reaction mixture;
- or
- 3) both of 1) and 2);
- such that at least one enantiomerically-enriched 2-halopropionic acid and/or salt thereof is enantioselectively produced.
A process which comprises subjecting at least one 2-halo-α,β-alkenoic acid and/or salt thereof, to asymmetric hydrogenation in the presence of
- (a) a catalyst that is
- 1) at least one enantiomerically-enriched (BINAP)Ru(II) catalyst;
- 2) catalytic species, if any, formed by the inclusion of at least one enantiomerically-enriched (BINAP)Ru(II) catalyst as a component used in making up the reaction mixture;
- or
- 3) both of 1) and 2);
- and
- (b) at least one alkali metal halide in which the halide is derived from a halogen atom of atomic number greater than 9 and/or at least one quaternary ammonium halide in which the halide is derived from a halogen atom of atomic number greater than 9;
- in at least one liquid alcohol reaction medium with which at least one alkali metal base is mixed;
- and at a pressure in the range of about 100 to about 3000 psig and a temperature in the range of about 0 to about 30° C., such that an enantiomerically-enriched 2-haloalkanoic acid or salt thereof is enantioselectively produced.
Dependencies are inferred from the claim text.