Sodium hydride → (1R,2S)-1'-benzyl-2-(1-benzyl-1H-indazol-6-yl)-5'-methylspiro[cyclopropane-1,3'-indolin]-2'-one

Participants

Reaction Conditions

Reaction Steps

To a 250 mL round bottom flask charged with 60% NaH (1.20 g, 30 mmol) was added anhydr. THF (20 mL) and the resulting mixture was cooled to 0° C. A solution of 1-benzyl-5-methylindolin-2-one (2.37 g, 10 mmol) in dry THF (25 mL) was added over 2 min, followed by rinsing with THF (5 mL). After stirring for 20 min at 0° C., a solution of (S)-1-(1-benzyl-1H-indazol-6-yl)ethane-1,2-diyl dimethanesulfonate (4.24 g, 10 mmol) in dry THF (45 mL) was added dropwise through dropping funnel over 40 min, followed by rinsing with THF (5 mL). After addition, the resulting mixture was stirred for 30 min at 0° C. (TLC showed completion) then left O/N at rt. After cooling to 0° C., the reaction mixture was poured into an Erlenmeyer flask containing ice (100 mL) and sat. NH4Cl (30 mL) and extracted with EtOAc (150 mL×2), dried (Na2SO4). After removal of solvents, the residue was transferred to a 100 mL RBF using 30 mL of EtOAc and crystals formed. Suction filtration gave the title compound as a beige solid (1.537 g). The filtrate was concentrated and purified by Biotage Isolera (20-30% EtOAc in hexane) and triturated with EtOAc/hexane to give 2nd crop as off white solid (1.560 g). The filtrate was purified using the above procedure to give 3rd crop as a beige solid (115 mg). Total 3.212 g (68%). 1H NMR (400 MHz, CDCl3) δ 8.02 (s, 1H), 7.63 (d, J=8.0 Hz, 1H), 7.36-7.20 (m, 9H), 7.14 (d, J=6.0 Hz, 2H), 6.94 (d, J=8.4 Hz, 1H), 6.80 (d, J=8.0 Hz, 1H), 6.64 (d, J=7.2 Hz, 1H), 5.62 (d, J=16.8 Hz, 1H, partially overlapping with s at 5.59), 5.59 (s, 1H, partially overlapping with d at 5.62), 5.55 (d, J=16.8 Hz, 1H), 5.08 (d, J=16.0 Hz, 1H), 4.97 (d, J=15.6 Hz, 1H), 3.48 (t, J=8.4 Hz, 1H), 2.30-2.25 (m, 1H), 2.02-1.96 (m, 1H), 1.85 (s, 3H); MS ESI 470.3 [M+H]+, calcd for [C32H27N3O+H]+ 470.2.

Provenance & Evidence