Reaction #2015

Reaction equation

BOP

D-Tryptophan allyl ester

triethylamine

N-benzyloxycarbonyl-α-methylalanine

→

desired product

Yield 84.5%

(R)-α-[(2-Benzyloxycarbonylamino-2-methyl-1-oxopropyl)amino]-1H-indole-3-propanoic acid, allyl ester

Yield 84.5%

Solvents

—

hexanes

ethyl acetate

methylene chloride

Conditions

Workup

1. 1
   Otherthe reaction quenched with saturated brine (5 ml)
2. 2
   OtherThe methylene chloride layer was separated
3. 3
   Dryingdried with magnesium sulfate
4. 4
   Filtrationfiltered
5. 5
   Otherthe volatiles removed under reduced pressure
6. 6
   Otherto leave a dark brown oil

Procedure

D-Tryptophan allyl ester (250 mg; 0.822 mmol), triethylamine (230 μl; 1.650 mmol) and N-benzyloxycarbonyl-α-methylalanine (167.9 mg; 0.826 mmol) were dissolved in dry methylene chloride (5 ml) and BOP (363.7 mg; 0.822 mmol) added. The reaction mixture was stirred at room temperature for 16 h and then the reaction quenched with saturated brine (5 ml). The methylene chloride layer was separated, dried with magnesium sulfate and filtered then the volatiles removed under reduced pressure to leave a dark brown oil. Chromatography of this oil on silica gel using ethyl acetate and hexanes 2:1 v/v afforded 322 mg (84.5%) of the desired product. FAB-MS:- calculated for C26H29N3O5 463.2; found 464.5 (M+1).

Source