Reaction #155404

Reaction equation

N-Boc-1(R)-amino-2(S)-hydroxy-cyclopentane-4(S)-carboxylic acid methyl ester

imidazole

TBSCl

HCl

→

desired acid

Yield 87.1%

N-Boc-1(R)-amino-2(S)-tert-butyldimethylsilyloxy-cyclopentane-4(S)-carboxylic acid

Yield 87.1%

Solvents

DCM

isopropanol

chloroform

NaOH

Conditions

Workup

1. 1
   Temperatureby heating at 40° C. for 1 hour
2. 2
   TemperatureThe reaction mixture was cooled to room temperature
3. 3
   Otherwas quenched with H2O (3 mL)
4. 4
   OtherThe organic layer was separated
5. 5
   Concentrationwas concentrated to dryness
6. 6
   Otherto yield a residue, which
7. 7
   TemperatureThe reaction was cooled to 0° C.
8. 8
   Otherthe organic layer was separated
9. 9
   Dryingdried over Na2SO4
10. 10
    Concentrationconcentrated to dryness

Procedure

To a stirring solution of N-Boc-1(R)-amino-2(S)-hydroxy-cyclopentane-4(S)-carboxylic acid methyl ester (0.622 g, 2.40 mmol) in DCM (1.9 mL) was added imidazole (0.164 g, 2.41 mmol), DMAP (0.047 g, 0.35 mmol) and TBSCl (0.363 g, 2.40 mmol) and the reaction was stirred at room temperature for 18 hours, followed by heating at 40° C. for 1 hour. The reaction mixture was cooled to room temperature, and was quenched with H2O (3 mL). The organic layer was separated and was concentrated to dryness to yield a residue, which was dissolved in isopropanol (6 mL) and 1M NaOH (2.9 mL), and the reaction was heated at 60° C. for 1 hour. The reaction was cooled to 0° C. and slowly acidified to pH 3 with 1M HCl (3 mL). After adding chloroform (18 mL), the organic layer was separated, dried over Na2SO4, and concentrated to dryness to yield the desired acid (0.75 g, 2.09 mmol, 87.1% yield).

Source