Process for manufacturing .alpha.,.alpha.'-diaminoalcohol

A process for the manufacture of 2-›3(S)-amino-2(R)-hydroxy-4-phenyl-butyl!-N-tert-butyl-decahydro-(4aS,8aS )-isoquinoline-3(S)-carboxamide of the formula ##STR18## which process comprises:

• a) reacting an L-phenylalanine lower alkyl ester with a chloroformic acid ester of the formula ClCOOR.sup.1, wherein R.sup.1 is lower alkyl, benzyl, or phenyl, to produce a diester of formula ##STR19## wherein R is lower alkyl and R.sup.1 is defined as above;
• b) reacting the resulting diester of the formula II with halogenated methyllithium to produce a halogenated .alpha.-aminoketone of formula ##STR20## wherein X is halogen and R.sup.1 is defined as above;
• c) reducing the resulting halogenated .alpha.-aminoketone of formula III to produce a halogenated .alpha.-amino catechol of formula ##STR21## wherein X and R.sup.1 are as defined above;
• d) cyclizing a resulting halogenated .alpha.-aminoalcohol of the formula IV with a base to produce an ›(S)-1-›(S)-oxiran-2-yl!-2-phenyl-ethyl!-carbamic acid ester of formula ##STR22## wherein R.sup.1 is as defined above;
• e) reacting the resulting ›(S)-1-›(S)-oxiran-2-yl!-2-phenyl-ethyl!-carbamic acid ester of formula V with N-tert-butyl-decahydro-(4aS,8aS)-isoquinoline-3(S)-carboxamide of formula ##STR23## to produce a methyl(1S,2R)-›1-benzyl-3-›(3S,4aS,8aS)-3-tert-butoxycarbamoyl-octahydro-i soquinoline-2-yl!-2-hydroxy-propyl!-carbamate of formula ##STR24## f) treating the resulting methyl(1S,2R)-›1-benzyl-3-›(3S,4aS,8aS)-3-tert-butoxycarbamoyl-octahydro-i soquinoline-2-yl!-2-hydroxy-propyl!-carbamate of formula VII with a base to produce the 2-›3(S)-amino-2(R)-hydroxy-4-phenyl-butyl!-N-tert-butyl-decahydro-(4aS,8aS )-isoquinoline-3(S)-carboxamide of formula I.