Oxygen → (3RS,4SR)-1-benzyl-3-(4-chloro-phenyl)-piperidine-4-carboxylic acid

Participants

Reaction Steps

A 185-mL stainless steel autoclave was charged under argon in a glove box (O2 content<2 ppm) with the hydrochloride salt of 1-benzyl-5-(4-chloro-phenyl)-1,2,3,6-tetrahydro-pyridine-4-carboxylic acid (7.00 g, 21.36 mmol), [Ru(OAc)2((R)-(6,6′-dimethoxybiphenyl-2,2′-diyl)bis(di-2-furylphosphine)] (81.30 mg, 0.11 mol), [Ru(OAc)2((S)-(6,6′-dimethoxybiphenyl-2,2′-diyl)bis(di-2-furylphosphine)] (81.30 mg, 0.11 mol), triethylamine (3.00 mL, 21.42 mmol) and methanol (120 mL). The hydrogenation was run for 20 h at 30° C. under 40 bar of hydrogen. After the pressure was released, the white suspension was evaporated to dryness to yield 9.58 g of the crude title compound. The crude product was dissolved in 1 M NaOH (45 mL). TBME (50 mL) was added, the aqueous layer was separated and diluted with water (250 mL). Under stirring 2 M HCl (20.5 mL) was added (pH value=6.0). The formed precipitate was filtered off and washed with water (50 mL). The filter cake was dissolved in methanol (100 mL) and the colorless solution evaporated to dryness to yield 5.13 g (70%) of the title compound. MS (m/e): 330.2 [(M+H)+].

Provenance & Evidence