Patent ID: 8288132

Claim:
Chemoenzymatic process for the preparation of an iminocyclitol of formula (I), (II), (III) or (IV): wherein: R 1 and R 2 are the same or different, and independently selected from the group consisting of: H, OH, hydroxymethyl, methyl, ethyl, butyl, pentyl, hexyl, octyl, isopropyl, isobutyl, 2-methylbutyl, and benzyl; R 3 is selected from the group consisting of: H, hydroxymethyl, hydroxyethyl, ethyl, butyl, pentyl, hexyl, octyl, dodecyl, isobutyl, isopropyl, isopentyl, 2-methylbutyl, benzyl, and phenylethyl; n: 0 or 1; the configurations of the carbon atoms to which R 1 and R 2 substituents are attached in the iminocyclitol of formula I are, the same or different, and independently selected from R and S; and the stereogenic centres * in the iminocyclitol of formula II, III or IV are, the same or different, and independently selected from R and S; the process comprising: i) an aldol addition catalyzed by a D-fructose-6-phosphate aldolase enzyme (FSA), wherein the FSA enzyme has an identity degree with the amino acid sequence of SEQ ID NO: 2 of at least 85%, between the dihydroxyacetone (DHA) and an acceptor aminoaldehyde, the aminoaldehyde corresponding to formula V, VI or VII: wherein R 1 , R 2 and n are as defined above; the configurations of the carbon atoms to which R 1 and R 2 substituents are attached in formula V and the stereogenic centre of formulae VI and VII are the same or different, and independently selected from R and S; and Cbz represents a benzyloxycarbonyl group; and ii) an intramolecular reductive amination of the addition adduct obtained in step (i) with H 2 , in the presence of a metallic catalyst, optionally being carried out said step (ii) with an aldehyde of formula R 3 â€”CHO, wherein R 3 is as defined above, resulting in a double reductive amination.