4-[[(2,4,6-Trimethylphenyl)sulfonyl]amino]-L-phenylalanine on Wang resin (0.30 g, 0.23 mmol), 2,2-dichloro-1-methylcyclopropane carboxylic acid (0.19 g, 1.14 mmol), BOP ((0.50 g, 1.14 mmol) and DIPEA (0.26 mL, 1.5 mmol) in N-methylpyrrolidinone (3 mL) was agitated for 3 hr. The mixture was filtered and the resin was washed with dichloromethane and methanol and was air dried. Treatment with 90% TFA in dichloromethane for 3 min effected cleavage from the resin. The mixture was filtered, the filtrate was concentrated and lyophilized from water to give N-[(2,2-dichloro-1-methylcyclopropyl)carbonyl]-4-[[(2,4,6-trimethylphenyl)carbonyl]amino]-L-phenylalanine as a white solid.
