Asymmetric synthesis of bicyclic amino acid esters

A process for producing a compound of formula IV:

• ##STR14## wherein:
• R.sub.1 and R.sub.2 may be the same or different and are selected from H;
• straight or branched (C.sub.1 -C.sub.5)alkyl;
• phenyl;
• and --(CH.sub.2).sub.n OSi (R.sub.3).sub.3, n=0-2, and R.sub.3 may be the same or different and is selected from (C.sub.4 -C.sub.5)alkyl and phenyl;
• and
• R.sub.4 is (C.sub.1 -C.sub.4) alkyl;
• which comprises:
• reacting a compound of formula I:
• ##STR15## wherein:
• R.sub.1 and R.sub.2 are as defined hereinabove;
• with a chiral compound of formula II, which contains a chiral auxiliary;
• ##STR16## wherein:
• R.sub.4 is as defined hereinabove;
• R.sub.5 is a straight or branched (C.sub.1 -C.sub.4)alkyl;
• and
• Ar is phenyl;
• substituted phenyl wherein the substitutents are selected from (C.sub.1 -C.sub.4)alkoxide, (C.sub.1 -C.sub.5) alkyl, nitro and phenyl;
• naphthyl;
• or substituted naphthyl wherein the substituents are selected from (C.sub.1 -C.sub.4)alkoxide, (C.sub.1 -C.sub.5)alkyl, and phenyl;
• in an inert solvent with an acid catalyst and a catalytic amount of water;
• and obtaining a compound of formula III:
• ##STR17## wherein R.sub.1, R.sub.2, R.sub.4, R.sub.5 and Ar are as defined hereinabove;
• removing, from the compound of formula III, the chiral auxiliary and reducing the olefin by hydrogenation using a transition metal catalyst and thereby obtaining a compound of formula IV wherein R.sub.1, R.sub.2, R.sub.4, and R.sub.5 are as defined hereinabove.