tert-butyl (3S)-3-{[1'-(diphenylmethyl)-2'-oxo-1,2'-dihydrospiro[1-benzofuran-3,3'-indol]-6-yl]oxy}pyrrolidine-1-carboxylate → tert-butyl (3S)-3-[(2'-oxo-1',2'-dihydrospiro[1-benzofuran-3,3'-indol]-6-yl)oxy]pyrrolidine-1-carboxylate

Participants

Reaction Conditions

Reaction Steps

A suspension of tert-butyl (3S)-3-{[1′-(diphenylmethyl)-2′-oxo-1′,2′-dihydrospiro[1-benzofuran-3,3′-indol]-6-yl]oxy}pyrrolidine-1-carboxylate (0.50 g, 0.85 mmol) in methanol (20 mL) was degassed by bubbling through nitrogen for one hour before palladium hydroxide on carbon (20%, 0.084 g) was added. The mixture was stirred under 120 psi hydrogen at 60° C. for 48 h. The mixture was filtered through a pad of celite, the filtrate was concentrated in vacuo. The obtained residue was recrystallized from ethyl acetate and hexanes to afford tert-butyl (3S)-3-[(2′-oxo-1,2′-dihydrospiro[1-benzofuran-3,3′-indol]-6-yl)oxy]pyrrolidine-1-carboxylate (0.25 g, 70%) as a colorless solid: 1H NMR (300 MHz, CDCl3) δ8.01 (br s, 1H), 7.29-7.09 (m, 1H), 7.12 (d, J=7.0 Hz, 1H), 7.02 (dd, J=7.5, 0.8 Hz, 1H), 6.92 (d, J=7.7 Hz, 1H), 6.66 (d, J=8.3 Hz, 1H), 6.47 (d, J=2.1 Hz, 1H), 6.33 (dd, J=8.3, 2.1 Hz, 1H), 4.96 (d, J=9.1 Hz, 1H), 4.81 (s, 1H), 4.69 (d, J=9.1 Hz, 1H), 3.64-3.37 (m, 4H), 2.22-1.96 (m, 2H), 1.45 (s, 9H); MS (ES+) m/z 445.0 (M+23).

Provenance & Evidence