Triphenylphosphine → Diethyl 1-((3-(tert-butoxycarbonyl)-2,2-dimethyloxazolidin-4-yl)methyl)-3-iodo-1H-pyrazole-4,5-dicarboxylate

Participants

Reaction Steps

To a stirred solution of triphenylphosphine (5.84 g, 22.25 mmol) in THF (20 mL) was added DIAD (4.50 g 22.25 mmol) dropwise at 0° C. and the resulting solution was stirred for 15 min. Intermediate 104C (3.0 g, 8.90 mmol) in THF (20 mL) was added slowly at 0° C. and stirred at room temperature for 45 min. Intermediate tert-butyl 4-(hydroxymethyl)-2,2-dimethyloxazolidine-3-carboxylate (2.470 g, 10.68 mmol) in THF (20 mL) was added at 0° C. and resulting solution was stirred at room temperature overnight. The volatiles were removed under reduced pressure and the crude compound was purified by silica gel chromatography (40 g REDISEP® column, eluting with 10-13% ethyl acetate in hexanes). Fractions containing the product were combined and evaporated to afford Intermediate 351A (3.5 g, 58.5%) as a pale yellow oil. MS(ES): m/z=552 [M+H]+; 1H NMR (300 MHz, DMSO-d6) δ ppm 4.53-4.18 (m, 6H), 3.96-3.82 (m, 2H), 1.50-1.21 (m, 2H).

Provenance & Evidence