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

Participants

Reaction Conditions

Reaction Steps

To a 100 mL flask charged with (1R,2S)-1′-benzyl-2-(1-benzyl-1H-indazol-6-yl)-5′-methylspiro[cyclopropane-1,3′-indolin]-2′-one (469 mg, 1 mmol) was added dry THF (2 mL) and the resulting mixture was stirred at 0° C. before KOtBu (1 M in THF, 18 mL, 18 mmol) was added over 2 min. After addition, the resulting mixture was stirred for 15 min at 0° C. and DMSO (1.85 mL) was added. Oxygen was bubbled through for 1 h and reaction turned from homogeneous to heterogeneous. LC-MS showed good conversion at 50 min. It was quenched with sat. NH4Cl. The above reaction was repeated on a larger scale using (1R,2S)-1′-benzyl-2-(1-benzyl-1H-indazol-6-yl)-5′-methylspiro[cyclopropane-1,3′-indolin]-2′-one (1.41 g, 3 mmol). After quenching with saturated NH4Cl, two reactions were combined, diluted with H2O and extracted with EtOAc (100 mL×2). Purification by Biotage Isolera (10-95% EtOAc in hexane) gave the title compound as a light solid (680 mg, 53%). 1H NMR (400 MHz, CD3OD) δ 8.02 (s, 1H), 7.67 (d, J=8.4 Hz, 1H), 7.46 (s, 1H), 6.94 (d, J=8.4 Hz, 1H), 6.85 (d, J=8.0 Hz, 1H), 6.81 (d, J=7.6 Hz, 1H), 5.78 (s, 1H), 3.32 (t, overlapping with MeOH residue), 2.20-2.12 (m, 2H), 1.87 (s, 3H); MS ESI 290.1 [M+H]+, calcd for [C18H15N3O+H]+ 290.1.

Provenance & Evidence