Combine 3-cyano-3-(3,4-dimethoxyphenyl)pentanedioic diethyl ester (1.3 g, 3.24 mmol) and cobalt(II)chloride hexahydrate (1.54 g, 6.48 mmol) in methanol (50 mL). While maintaining the temperature at or below 20° C. with an ice-bath, add portionwise sodium borohydride (2.17 g, 57 mmol). After the addition is complete, allow the reaction mixture to stand at ambient temperature for 18 hours. Evaporate the reaction mixture in vacuo to obtain a residue. Partition the residue between dichloromethane and 1M hydrochloric acid solution. Extract the aqueous layer several times with dichloromethane, combine the organic layers, dry over Na2SO4, filter, and concentrate in vacuo to obtain a residue. Chromatograph the residue on silica gel eluting with 20/1 ethyl acetate/methanol. Remove residual solvent in vacuo at 82° C. to give the title compound: Rf=0.74 (silica gel, 5/1 ethyl acetate/methanol); mp; 116-118° C. Elemental Analysis calculated for C16H21NO5: C 62.53; H 6.89; N 4.56; Found: C 62.52; H 6.85; N 4.50.
