A suspension of 4-piperazin-1-ylbenzonitrile hydrochloride (1.30 g, 5.00 mmol) and 3,3-diphenylacrylaldehyde (1.56 g, 7.50 mmol)) in dichloromethane (10 mL) and methanol (10 mL) was neutralized to pH 5 with diisopropylethylamine, treated with polymer-supported cyanoborohydride (2.47 mmol/g, 6 g, 14.82 mmol), shaken at room temperature for 24 hours, and filtered. The resin was washed with 1:1 dichloromethane/methanol (10 mL×3) and the combined filtrates were concentrated. The concentrate was purified by silica gel chromatography eluting with a gradient from 10%-50% ethyl acetate/hexanes to provide the desired product (1.60 g, 84%). MS (CI) m/e 380 (M+H)+.
