Reaction #86651

Reaction equation

triphenylphosphine

N-Boc-serine methyl ester

ethyl chloroformate

triethylamine

Allyl alcohol

→

(S)-3-Allyloxy-2-tert-butoxycarbonylamino-propionic acid methyl ester

Solvents

THF

EtOAc

THF

diethyl ether

Conditions

Workup

1. 1
   workup.ADDITIONwere added
2. 2
   Otherwas removed by suction filtration
3. 3
   ConcentrationThe filtrate was concentrated in vacuo
4. 4
   workup.DISSOLUTIONthe residue dissolved in THF (4 mL)
5. 5
   workup.STIRRINGThe mixture was stirred at rt for twenty min
6. 6
   workup.STIRRINGThe reaction mixture was stirred at rt for a further 18 h
7. 7
   Concentrationbefore being concentrated in vacuo
8. 8
   OtherThe crude material was purified by flash chromatography on silica using a gradient of EtOAc and (50/70) petroleum ether
9. 9
   Otherto yield a yellow oil, 1.25 g, 21%

Procedure

Allyl alcohol (1.97 mL, 29.0 mmol) was dissolved in diethyl ether (20 mL). This was cooled in ice before ethyl chloroformate (0.304 mL, 31.9 mmol) and triethylamine (0.445 mL, 31.9 mmol) were added. After stirring in ice for 20 mins the resultant white precipitate was removed by suction filtration. The filtrate was concentrated in vacuo and the residue dissolved in THF (4 mL). To the resultant solution a solution of allyl palladium chloride dimer (0.0849 g, 0.232 mmol) and triphenylphosphine (0.266 g, 1.02 mmol) in THF (3 mL) was added. The mixture was stirred at rt for twenty min and to this was added a solution of N-Boc-serine methyl ester (obtained from GL Biochem (Shanghai) Ltd., Shanghai, China) (5.00 g, 2.32 mmol) in THF (20 mL). The reaction mixture was stirred at rt for a further 18 h before being concentrated in vacuo. The crude material was purified by flash chromatography on silica using a gradient of EtOAc and (50/70) petroleum ether to yield a yellow oil, 1.25 g, 21%. Rf=0.27 (1/6 EtOAc/(50/70) petroleum ether).

Source