Bromide ion → Methyl 2-[(tert-butoxycarbonyl)amino]pent-4-ynoate

Participants

Reaction Steps

To an ice cooled suspension of the product of Example 2 (4.00 g, 16.2 mmol) and zinc dust (2.63 g, 40.5 mmol) in DMF (30 mL) under nitrogen was added slowly via syringe propargyl bromide (80% w/w in toluene) (6.02 g, 40.5 mmol). The bromide was added at such a rate as to maintain the internal temperature between 20°-25° C., then stirred at that temperature for an additional 1 hour. The reaction mixture was diluted with 100 mL of EtOAc, washed successively with 0.5N HCl (200 mL), sat'd NaHCO3 (200 mL) and sat'd NaCl and then dried (MgSO4). After filtration and concentration under reduced pressure, the residue was purified by filtration through a bed of silica gel (30% EtOAc/hexane)to give 3.59 g (97%) of product as a colorless oil after concentration under reduced pressure.

Provenance & Evidence