Reaction #632035

Reaction equation

(−)-2,3-dibenzoyl-L-tartaric acid

acetic anhydride

→

title compound ( 29 )

(3R,4R)-2,5-Dioxo-3,4-dibenzoyloxy-3,4-dihydrofuran

Conditions

Workup

1. 1
   OtherTo a 3-necked 5 L round bottom flask fitted with a mechanical stirrer
2. 2
   workup.DISSOLUTIONgradually dissolved
3. 3
   Otherto crystallize in the reaction mixture
4. 4
   Temperaturethe suspension was then cooled to 25° C
5. 5
   FiltrationThe product was collected by filtration
6. 6
   Washwashed with 10% acetone in hexane (2×1 L)
7. 7
   Otherdried in a vacuum oven at 50° C. overnight

Procedure

To a 3-necked 5 L round bottom flask fitted with a mechanical stirrer and a Teflon coated thermocouple was added (−)-2,3-dibenzoyl-L-tartaric acid (1000 g, 2.79 mol) followed by acetic anhydride (2 L). The suspension was stirred and heated to 85° C. for 2 h during which time the starting material gradually dissolved. A short time thereafter, the product began to crystallize in the reaction mixture and the suspension was then cooled to 25° C. The product was collected by filtration, washed with 10% acetone in hexane (2×1 L), and dried in a vacuum oven at 50° C. overnight to afford the title compound (29) as a white solid. 1H NMR (CDCl3, 400 MHz): δ 6.0 (s, 2H), 7.45 (app. t, 4H), 7.65 (app. t, 2H), 8.05 (d, 4H).

Source