Pentanal → benzyl N-[1-(2-fluoropentyl)piperidin-4-yl]carbamate

Participants

Reaction Conditions

Reaction Steps

(5S)-(−)-2,2,3-Trimethyl-5-benzyl-4-imidazolidinone dichloroacetic acid (90 mg, 0.259 mmol), N-fluorobenzenesulfonimide (484 mg, 1.53 mmol), 2-propanol (0.4 ml) and tetrahydrofuran (dehydrated) (3.6 ml) were mixed at room temperature. The reaction mixture was cooled to −10° C., and pentanal (0.175 ml, 1.67 mmol) was then added, followed by stirring for three hours and 20 minutes while naturally warming from −10° C. to room temperature. Benzyl N-(piperidin-4-yl)carbamate obtained in Example 1b (304 mg, 1.3 mmol) and sodium triacetoxyborohydride (600 mg, 2.83 mmol) were added to the reaction mixture, which was stirred at room temperature for 15 hours and 40 minutes. Water and an aqueous sodium bicarbonate solution were added to the reaction mixture, the insoluble matter was removed by filtration, and the resulting filtrate was extracted with ethyl acetate twice. The organic layer was washed with brine and dried over anhydrous sodium sulfate, and the solvent was distilled off. The residue was purified by silica gel column chromatography (silica gel, elution solvent: ethyl acetate/heptane) to give a chiral form mixture of the title compound (44 mg, yield 10.5%).

Provenance & Evidence