A 25-mL round-bottom flask was charged with phosphonate (153 mg, 0.325 mmol) in
THF (2.15 mL), which was equipped with a stir bar and cooled to -78ºC to increase the yield of the cis isomer. The round-bottom flask was charged with potassium
tert-butoxide (1M in THF, 0.325 mL) added dropwise and stirred for 15 minutes. Molecule 20 (100 mg, 0.217 mmol) was added
dropwise as a solution in 2.15 mL THF. The reaction was allowed to warm to 0 degrees Celsius over 2 hours. The flask was charged with saturated NH
4Cl (2 mL) to quench the reaction. The reaction mixture was diluted with ethyl acetate (10 mL), and washed with brine (10 mL). The combined organic layers were dried over sodium sulfate, filtered, and concentrated in vacuo. The product was purified by
column chromatography (3:1 to 1:1 to 0:1 Hexanes:Ethyl Acetate) to give pipercyclobutanamide.
a technique used to separate substances by introducing the original substance onto the top of a column packed with silica gel. The compounds become separated because they pass through the column at different rates depending on the affinity of each substance for the silica and the solvent. Each compound is collected separately in beakers as they pass through the column.
slowly and carefully added drop by drop, using an addition funnel or a pipette.
