Methanol → HCID 24752609, compound

Participants

Reaction Steps

In a glove box an autoclave was charged with 4-o-tolyl-5,6-dihydro-2H-pyridine-1,3-dicarboxylic acid 1-tert-butyl ester (2.5 g), [Ru(OAc)2 ((R)-(2-furyl)-MeOBIPHEP)] (24 mg), triethylamine (1.1 mL) and methanol (25 mL). The asymmetric hydrogenation was run for 60 h at 80° C. under 40 bar of hydrogen. After cooling to room temperature the pressure was released from the autoclave, the methanol solution was diluted with tert-butyl methyl ether (320 mL) and extracted with 1 M aqueous sodium hydroxide solution (2×, 320 mL). The aqueous layer was poured on ice, acidified with ice-cold 2 M aqueous hydrochloric acid solution to pH 1 and extracted with ethyl acetate (3×). The combined organic layers were dried (Na2SO4), filtered and concentrated in vacuo and triturated from n-heptane to give (3S,4S)-4-o-tolyl-piperidine-1,3-dicarboxylic acid 1-tert-butyl ester as a white solid, MS: 318.2.

Provenance & Evidence