1,2-Dichloroethane → tert-butyl N-((2S)-1-oxopentan-2-yl)carbamate
Reaction equation
[C:1]([NH:8][C@H:9]([CH2:13][OH:14])[CH2:10][CH2:11][CH3:12])([O:3][C:4]([CH3:7])([CH3:6])[CH3:5])=[O:2].C1(C)C=CC=CC=1.C(Cl)CCl.ClC(Cl)C(O)=O>CS(C)=O>[C:1]([NH:8][C@H:9]([CH:13]=[O:14])[CH2:10][CH2:11][CH3:12])([O:3][C:4]([CH3:5])([CH3:7])[CH3:6])=[O:2]Participants
6
Conditions
- Temperature
- 0 °C
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 washed successively with 1 N 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).
Workup
- additionAfter addition
- temperatureto warm to room temperature over a period of 2 h
- concentrationThe reaction mixture was concentrated
- customto remove the toluene
- dissolutiondissolved in ethyl acetate
- washThe solution washed successively with 1 N sodium bisulfate, saturated sodium bicarbonate and brine
- dry with materialdried over sodium sulfate
- filtrationfiltered
- concentrationconcentrated
Sources & evidence
- ORD record
- ord-0a2beae3e1df40098ad56f2c0215fede
- Source dataset
- uspto-grants-2009_09
- Patent number
- US07592316B2
Reaction notes
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