New chiral modifiers in enantioselective heterogeneous catalytic hydrogenation of ethyl pyruvate over Pt/Al2O3:: chiral amino alcohols derived from piperidine

New chiral and enantiopure erythro and threo 1,-2-amino-alcohols 4a and 4b hm,e been shown to accelerate the heterogeneous catalytic hydrogenation of ethyl pyruvate as much as cinchonidine does (with 77-100%, conversion within 2 h), A diastereo dependence of the enantioselectivity is clearly observed between the erythro and threo isomers. Moreover enantiomeric ratios up to 86,14 have been obtained under classical and not optimized conditions with the erythro-isomer of the naphthyl compound 4a making this compound very promising. (C) 2002 Elsevier Science Ltd. All rights reserved.