Abstract: A process for the asymmetric transformation of a racemic compound of formula (I) wherein R1 is H or a alkyl group having up to 20 carbon atoms, R2 is H, or an alkyl, aryl, alkaryl or aralkyl group having up to 20 carbon atoms, and X is H, a halogen atom, tert-butyl, or any other removable substituent, comprises reaction of racemic compound (I) with an enantiomerically-enriched acid HY*, wherein Y* is a chiral group, to form a diastereomeric salt of compound (I) having Y* as a counterion. The salt obtained can then be reduced to give enantiomerically-enriched galanthamine, or a derivative thereof.

Abstract: A process for the preparation of an enantioenriched sulfone of formula (1), which comprises asymmetric hydrogenation of vinyl sulfone of formula (2) wherein R1 and R2 are each independently a hydrocarbon group of less than 20 carbons atoms, optionally substituted at any position, or either of R1 and R3 is H, and X is a coordinating group, in the presence of a stereoselective chiral catalyst.

Abstract: The subject invention pertains to compounds of the formula Y.sup.1 Y.sup.2 N--(CH.sub.2).sub.4 --CH.dbd.C(Ph)--X wherein Y.sup.1 and Y.sup.2 are independently H or a removable blocking group, or Y.sup.1 and Y.sup.2 together are a removable divalent blocking group; and X is COOCH.sub.3 or a group convertible thereto. Such a compound may be cyclised, by Michael addition, to give methylphenidate, if necessary after removing blocking group(s) and converting X to COOCH.sub.3. The subject invention also pertains to methods for preparing compounds of the invention.

Abstract: The subject invention concerns a process for preparing a compound of formula (3) ##STR1## in enantio-enriched form, comprising reducing a compound of formula (4) ##STR2## using an asymmetric enantiospecific reductant, wherein A.sup.1 .dbd.A.sup.2 .dbd.H or A.sup.1, A.sup.2 .dbd.O; B.sup.1 .dbd.B.sup.2 .dbd.H or B.sup.1, B.sup.2 .dbd.O; Z.dbd.H, C.sub.1-20 alkyl or a precursor thereof, or a removable protecting group for nitrogen, e.g, acyl or alkyloxycarbonyl; Y.dbd.H or a substituent; R.sup.1 .dbd.C.sub.1-20 alkyl; and R is an optional, additional substituent.

Abstract: A process for racemising an optically-enriched chiral amine of the formula: R.sup.1 --CH(NR.sup.3 R.sup.4)--R.sup.2, wherein R.sup.1 is aromatic or unsaturated alkyl; R.sup.2 is aromatic or alkyl; and R.sup.3 and R.sup.4 are independently selected from hydrogen, alkyl and aryl; and wherein any combination(s) of two of the R groups may form a ring; comprises treatment of the optically-enriched amine with a metal hydroxide in an aprotic polar solvent.