CHIRAL C-2-SYMMETRICAL 2,5-DISUBSTITUTED PYRROLIDINE DERIVATIVES AS CHIRAL CATALYST LIGANDS IN THE REACTION OF DIETHYLZINE WITH ARYLADLDEHYES

Two kinds of chiral C-2-symmetric 2,5-disubstituted pyrrolidine derivatives having a beta-aminoalcohol moiety were successfully synthesized and their catalytic abilities of asymmetric induction were examined in the reaction of diethylzinc with arylaldehydes. The production of sec-alcohols in high yields and high enantiomeric excesses having the R-configuration could be achieved when N-(2',2'-diphenyl-2'-hydroxyethyl)-(2R, 5R) -bis(methoxymethyl)pyrrolidine was used as a chiral ligand. On the other hand, when N-methyl-(2R, 5R)-bis(diarylhydroxymethyl)pyrrolidine was used as a catalyst, the enantiomeric excesses of the sec-alcohols went down and the inversion of the enantioselectivity was observed in the reaction of m-chloro-, p-chloro-, and m-fluorobenzaldehyde with diethylzinc.