Commercially available N-Boc protected t-leucine (2) was converted to its thioester derivative 3 using DPDTC in environmentally preferrable EtOAc 13 containing catalytic DMAP at rt. Product 3 was then processed via simple inflask treatment with aqueous base, followed (after removal of the aqueous phase and EtOAc) by addition of bicyclic proline 4, N-methylmorpholine (NMM), and EtOAc. Gentle heating led to the desired amide bond in product 5. This newly formed peptide containing a methyl ester originally present in 4, was then hydrolyzed with LiOH in aqueous THF, after which the reaction mixture was neutralized with aqueous HCl and then extracted with minimal EtOAc to afford 6 (78% over 3 steps). It is noteworthy that the product did not require purification since the small amounts of impurities present, primarily 2,2'-dipyridyldisulfide, were of no synthetic consequence. It was, however, necessary to adjust the stoichiometry of reagents used in the second thioesterification step based on the amounts of impurities present in crude 6 (as determined by quantitative NMR).