Chloroform → 1-oxoheptyl-D-allo-Threonine

Participants

Reaction Steps

A solution of n-heptanoyl chloride (440 mL, 2.83 mmol) in THF (250 mL) is added dropwise, over a period of 30 min, to a cold (-5 to 0° C., vigorously stirred mixture of D-allo-Thr (300 mg, 2.51 mmol) and 2N aq. NaOH (3.5 mL, 7.0 meq) in THF (4.0 mL). The resulting mixture is stirred for 2 h at the same temperature and overnight at room temperature. The volatiles are removed and the residue is diluted with o water and acidified, using conc. HCl. The mixture is extracted with EtOAc and the combined organic solution is washed with brine, dried, filtered, and concentrated to provide crude 2c-1 (420 mg, containing 10% excess heptanoyl reagent) which solidifies upon standing. NMR δ1.28 (d, J=6.5, 3H), 4.20 (m, 1H), 4.61 (dd, J=3.4, 6.6, 1H), 6.56 (br d, J=6.9, 1H); [α]D26 -38±2 (CHCl3).

Provenance & Evidence