(D)-2-tert-Butoxycarbonylamino-5,5-difluoro-5-phenyl-pentanoic acid: synthesis and incorporation into the growth hormone secretagogues.

Abstract The first enantioselective synthesis of ( d )-2- tert -butoxycarbonylamino-5,5-difluoro-5-phenyl-pentanoic acid 3 was achieved. The incorporation of the titled compound into growth hormone secretagogue (GHS) compounds resulted in new analogs 10 and 16 , both of which had significantly increased in vitro potency. The compound 10 also showed improved in vivo efficacy as well as pharmacokinetic properties in rat models.