Abstract: Novel, chiral diarsine compounds, which are present in the (R)- or (S)- or (rac)-form, of the formula ##STR1## wherein R signifies an optionally substituted aryl from the group of phenyI, naphthyl, furyl and thienyl; C.sub.3-8 -cycloalkyl or C.sub.1-8 -alkyl;R.sup.1, R.sup.2, R.sup.3 each independently signify C.sub.1-8 -alkyl, C.sub.1-8 -alkoxy, aryloxy, F or Cl,R.sup.2 and R.sup.3 each independently also signify hydrogen orR.sup.1 and R.sup.2 together signify tetramethylene or a benzo or benzofuro system or dioxymethylene on the respective benzene ring; orR.sup.2 and R.sup.3 together signify dioxymethylene,and the manufacture of the diarsine compounds of formula I, as well as complexes of the compounds of formula I with Group VIII metal and their use for enantioselective reactions.

Abstract: A process for the manufacture of optically active (R)- or (S)-1-(4-methoxy-benzyl)-1,2,3,4,5,6,7,8-octahydro-isoquinoline adducts of the formula ##STR1## wherein HX signifies a mineral acid from the group of HBF.sub.4, H.sub.2 SO.sub.4, HPF.sub.6, HBr, HI, HCl,HSbF.sub.6 or HClO.sub.4, or a strong organic acid from the group of C.sub.1-8 -alkylSO.sub.3 H, picric acid, formic acid, a lower alkylsulphonic acid or arylcarboxylic acid or a dicarboxylic acid,from a compound of the formula ##STR2## wherein HX has the significance given above, by asymmetric hydrogenation in the presence of a complex consisting of optically active diphosphine ligands with iridium, optionally in the presence of an additive.

Abstract: Optically active .alpha.-bromo- or .alpha.-chlorocarboxylic compounds of the formula ##STR1## wherein X is bromine or chlorine;M is hydrogen, NR.sub.4.sup.+1 or a cation of an alkali or alkaline earth metal;R.sup.1 is hydrogen or lower alkyl;n is 0 or 1;R is hydrogen, C.sub.1 -C.sub.20 alkyl, or C.sub.1 -C.sub.20 alkyl substituted in the terminal position with --NR.sup.2.sub.2, --COOR.sup.2, --OR.sup.3, a free or protected --CHO group or a ring A;R.sup.2 is hydrogen or a lower alkyl;R.sup.3 is hydrogen or a protecting group;ring A is an unsubstituted or substituted ring; and* is a center of chirality,are prepared by enantioselectively hydrogenating, in the presence of a ruthenium complex of an optically active diphosphine ligand, a (Z)-.alpha.,.beta.-unsaturated compound of the general formula ##STR2## wherein R, n, X and M are as defined above.

Abstract: A process for the asymmetric hydrogenation of a compound of the formula ##STR1## wherein each R, independently, is alkyl, arylmethyl, aryl, alkoxy, arylmethoxy or aryloxy or both R's, taken together, are methylene, ethylene or 1,2-phenylene and n is 1,2 or 3,or of a salt thereof to a compound of the formula ##STR2## in the form of an (S) or (R) enantiomer, wherein R and n have the significances given above, using an optically active ruthenium-diphosphine complex as catalyst, is described. The preparation of the compounds of formula II, as well as the compounds of formula II, which form a further object of the invention, are also described.

Abstract: The compounds of the formula ##STR1## wherein R is OH, NH.sub.2, lower-alkyl-NH or phenyl-lower alkyl-NH are presented. These compounds can be catalytically hydrogenated to the corresponding .alpha.-aminocarboxylic acid derivatives which are intermediates in the synthesis of therapeutic pseudopeptides.