Reaction #632037

Reaction equation

( 11 )

O-(1-Isobutanoyloxyisobutoxy) S-Methyl Thiocarbonate

( 30 )

1-Hydroxy-(3R,4R)-2,5-Dioxo-3,4-dibenzoyloxypyrrolidine

peracetic acid

acetic acid

→

title compound ( 28 )

Yield 25.0%

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

Yield 25.0%

Solvents

1,2-dichloroethane

Conditions

Workup

1. 1
   OtherTo the stirred reaction mixture
2. 2
   Temperaturemaintaining the temperature between 15 and 22° C
3. 3
   TemperatureThis temperature was maintained for an additional 12 h during which time a white precipitate
4. 4
   Otherwas formed
5. 5
   TemperatureThe reaction mixture was further cooled to 3-4° C.
6. 6
   Filtrationthe product collected by filtration
7. 7
   Washwashed with hexane (2×1 L)
8. 8
   OtherThe product was dried in vacuo

Procedure

A 3 L three necked round bottom flask fitted with a mechanical stirrer, Teflon coated temperature probe and an addition funnel was charged with (11) (234 g, 1 mol), (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 the title compound (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).

Source