Acetic Acid → (1S)-1-[((3R,4R)-2,5-Dioxo-3,4-dibenzoyloxypyrrolidinyl)-oxycarbonyloxy]-2-methylpropyl 2-methylpropanoate

Participants

Reaction Conditions

Reaction Steps

In a third step (Step C), a 3 L three necked round bottom flask fitted with a mechanical stirrer, Teflon coated temperature probe and an addition funnel was charged with compound (11) (234 g, 1 mol), compound (30) (330 g, 0.95 mol), and 1,2-dichloroethane (2200 mL). The reaction mixture was cooled under a nitrogen atmosphere in an ice water bath to 15° C. To the stirred reaction mixture was added a 39% solution of peracetic acid in dilute acetic acid (500 mL, 2.94 mol) over 2 h, maintaining the temperature between 15 and 22° C. This temperature was maintained for an additional 12 h during which time a white precipitate was formed. The reaction mixture was further cooled to 3-4° C., the product collected by filtration, and washed with hexane (2×1 L). The product was dried in vacuo, yielding (1S)-1-[((3R,4R)-2,5-dioxo-3,4-dibenzoyloxypyrrolidinyl)-oxycarbonyloxy]-2-methylpropyl 2-methylpropanoate (28) (128 g, 0.24 mol, 25% yield). The diastereomeric purity of the product was determined to be >99% d.e. by HPLC using a chiral column. 1H NMR (CDCl3, 400 MHz): δ 1.0 (d, 6H), 1.2 (dd, 6H), 2.1 (m, 1H), 2.65 (m, 1H), 6.0 (br. s, 2H), 6.6 (d, 1H), 7.45 (app. t, 4H), 7.65 (app. t, 2H), 8.05 (d, 4H).

Provenance & Evidence