Diisopropylethylamine → HCID 86726816, compound

Participants

Reaction Conditions

Reaction Steps

To a −40° C. solution of (4R)-4-benzyl-3-(cyclopropylacetyl)-1,3-oxazolidin-2-one (2.0 g, 7.7 mmol) in anhydrous DCM (45 mL), a solution of 1.0 M titanium tetrachloride in DCM (9.3 mL) was added drop-wise under an atmosphere of nitrogen to form a yellow slurry. After 10 min., DIPEA (3.36 mL, 19.3 mmol) was added drop-wise, changing the color from yellow to deep purple. The reaction mixture was allowed to warm gradually to −20° C. while stirring over 1 h. The reaction mixture was again cooled to −40° C., and a solution of tert-butyl (4R)-4-formyl-2,2-dimethyl-1,3-oxazolidine-3-carboxylate (1.8 g, 7.85 mmol) (Aldrich) in anhydrous DCM (5 mL) was added drop-wise. The reaction mixture was allowed to warm gradually to 0° C. over 1 h and then allowed to stir for an additional 1.5 h at 0° C. The reaction was quenched by the addition of saturated NH4Cl (aq.) (15 mL). After separation of the two layers that resulted, the organic layer was washed with water and brine, dried over Na2SO4, concentrated under reduced pressure and purified by flash chromatography (120 g silica gel, eluting with 0-60% EtOAc/hexanes) to afford the sub-title compound (1.9 g, 50%). LC/MS (ESI) m/z calc. for C26H36N2O7Na: 511.2 [M+Na]+. found 511.1.

Provenance & Evidence