Reaction #1771996

Reaction equation

dichloroacetic acid

Boc-norvalinol

toluene

EDC

→

Boc-norvalinal

Solvents

dimethylsulfoxide

Conditions

Workup

1. 1
   workup.ADDITIONAfter addition
2. 2
   Temperatureto warm to room temperature over a period of 2 h
3. 3
   ConcentrationThe reaction mixture was concentrated
4. 4
   Otherto remove the toluene
5. 5
   workup.DISSOLUTIONdissolved in ethyl acetate
6. 6
   WashThe solution was washed successively with 1N sodium bisulfate, saturated sodium bicarbonate and brine
7. 7
   Dryingdried over sodium sulfate
8. 8
   Filtrationfiltered
9. 9
   Concentrationconcentrated

Procedure

To Boc-norvalinol (7.77 g, 38 mmol), in anhydrous dimethylsulfoxide (153 mL) and toluene (153 mL) was added EDC (73.32 g, 382 mmol). After the solution was cooled to 0° C., dichloroacetic acid (15.8 mL, 191 mmol) was added dropwise. After addition was complete, the reaction was stirred for 15 min. The solution was allowed to warm to room temperature over a period of 2 h. The reaction mixture was concentrated to remove the toluene, then dissolved in ethyl acetate. The solution was washed successively with 1N sodium bisulfate, saturated sodium bicarbonate and brine, dried over sodium sulfate, filtered and concentrated to afford crude Boc-norvalinal which was used directly in the next step. TLC Rf=0.84 (40% ethyl acetate/hexanes).

Source