ENANTIOMERIC HALORUTHENOCENIUM SALTS - SYNTHESIS OF THE FIRST REPRESENTATIVES WITH THE USE OF ASYMMETRIC REDUCTION AND ASYMMETRIC CYCLOPALLADATION

Optically active substituted ruthenocenes, (+)-RcCH(OH)Ph (I), (-)-RcC H(Me)Ph (+) and (+)-1-hydroxymethyl-2-methylruthenocene (VIII) react w ith molecular iodine to yield the corresponding iodoruthenocenium salt s Ia, IIa, VIIIa with I-3(-) anions. Reduction of these salts using, f or example, NaBH4 regenerates the optically active starting compounds. Ruthenocenes with electron-withdrawing substituents (COMe, COPh, COOM e) remain intact when treated with I-2, Fe(III), or Ce(IV). Asymmetric cyclopalladation of RcCH(2)NMe(2) is described for the first time as the initial step of the reaction sequence leading to (+)-VIII.