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 have 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.