Lithium Hydroxide → (S)-tert-butyl 4-(4-(benzyloxycarbonylamino)-5-(tert-butyldimethylsilyloxy)pentanoyl)piperazine-1-carboxylate

Participants

Reaction Steps

To a solution of (S)-benzyl 2-((tert-butyldimethylsilyloxy)methyl)-5-oxopyrrolidine-1-carboxylate (39 g, 0.107 mol) in THF (214 mL) was added LiOH (2 N, 107.4 mL). The reaction mixture was stirred at RT overnight, concentrated to dryness, and dissolved in DMF (100 mL). To the resulting solution were added HBTU (48.9 g, 0.13 mmol) and Boc-piperazine (24 g, 0.13 mol). The reaction mixture was stirred at RT for 1 h and diluted with water (200 mL) and EtOAc (500 mL). The organic layer was washed with water, dried over Na2SO4, filtered and concentrated. The residue was purified on silica gel column using a mixture of EtOAc and hexanes to give (S)-tert-butyl 4-(4-(benzyloxycarbonylamino)-5-(tert-butyldimethylsilyloxy)pentanoyl)piperazine-1-carboxylate (33.3 g, 56.5%). LRMS (M+H) m/z 550.3.

Provenance & Evidence