Acetic Acid → Ethyl 4-(dibenzylamino)-2-ethylcyclopentanecarboxylate

Participants

Reaction Conditions

Reaction Steps

A round-bottom flask was charged with ethyl 2-ethyl-4-oxocyclopentanecarboxylate (95.9 g, 521 mmol, Preparation #DD.1) and DCE (1.8 L). The solution was cooled to about 0° C. and AcOH (45 mL, 780 mmol) and dibenzylamine (120 mL, 625 mmol) were added drop-wise, resulting in formation of a thick suspension. The reaction mixture was warmed to about 10° C. and additional DCE (500 mL) was added. Sodium triacetoxyborohydride (166 g, 781 mmol) was added portion-wise and the reaction mixture was stirred at room temperature for about 20 h. The reaction mixture was slowly poured into stirred saturated aqueous NaHCO3 (1.5 L), followed by the portion-wise addition of solid sodium bicarbonate (175 g). The mixture was stirred for about 2 h and the organic layer was separated, dried over anhydrous Na2SO4, and concentrated to dryness under reduced pressure. The crude yellow oil was purified by silica gel chromatography using EtOAc/heptane as eluant (0-20% EtOAc in heptane). The solvent was removed under reduced pressure to yield ethyl 4-(dibenzylamino)-2-ethylcyclopentanecarboxylate (136.6 g, 72%) as a white solid: LC/MS (Table 2, Method a) Rt=3.26 min; MS m/z: 366 (M+H)+

Provenance & Evidence