Patent ID: 8258338

Claim:
A process for the preparation of N-monosubstituted β-aminoalcohol sulfonates of formula wherein R 1 is C 6-20 aryl or C 4-12 heteroaryl, each optionally being substituted with one or more halogen atoms and/or one or more C 1-4 alkyl or C 1-4 alkoxy groups, R 2 is selected from the group consisting of C 1-4 alkyl, C 3-8 cycloalkyl and C 6-20 aryl, each aryl optionally being substituted with one or more halogen atoms and/or one or more C 1-4 alkyl or C 1-4 alkoxy groups, and wherein R 3 is selected from the group consisting of C 1-18 alkyl, C 6-20 cycloalkyl, C 6-2 O aryl and C 7-20 aralkyl residues, comprising the steps of a) reacting a mixture comprising (i) a methyl ketone of formula wherein R 1 is as defined above, (ii) a primary amine of formula H 2 N—R 2 V, wherein R 2 is as defined above, and (iii) formaldehyde or a source of formaldehyde selected from the group consisting of formaldehyde in aqueous solution, 1,3,5-trioxane, paraformaldehyde and mixtures thereof, in the presence of a sulfonic acid of the formula R 3 —SO 2 —OH VI wherein R 3 is as defined above, optionally in an organic solvent, said organic solvent optionally containing water, to afford a β-aminoketone sulfonate of formula wherein R, R 2 and R 3 are as defined above, and b) asymmetrically hydrogenating said sulfonate, to afford a β-aminoalcohol sulfonate of formula I, wherein R 1 , R 2 and R 3 are as defined above, in the presence of a base and a catalyst, the catalyst comprising a transition metal and a diphosphine ligand, at a hydrogen pressure of 5 to 50 bar, in a polar solvent, optionally in the presence of water.