Hydrochloric Acid → tert-butyl 6-hydroxy-8-phenylsulfonyl-3,4-dihydrobenzofuro[3,2-c]pyridine-2(1H)-carboxylate

Participants

Reaction Conditions

Reaction Steps

A mixture of the product of Example 44, step C (1.41 g, 3.14 mmol), di-palladium-tris(dibenzylideneacetone) (575 mg, 0.62 mmol), potassium hydroxide (387 mg, 6.91 mmol) and 2-(di-tert-butylphosphino)-2′,4′,6′-triisopropyl-3,4,5,6-tetramethyl-1,1′-biphenyl (121 mg, 0.25 mmol) in water (14 mL) and 1,4-dioxane (14 mL) was heated to 110° C. for 24 h. After cooling to ambient temperature, the reaction mixture was neutralized with 1N aqueous HCl, filtered through celite bed and extracted with ethyl acetate (4×30 mL). The combined organic extracts were washed with brine, dried over Na2SO4 and concentrated in vacuo to give the crude product which was purified by column chromatography (SiO2, 7:3 hexanes/ethyl acetate) providing tert-butyl 6-hydroxy-8-phenylsulfonyl-3,4-dihydrobenzofuro[3,2-c]pyridine-2(1H)-carboxylate (470 mg, 34%): 1H NMR (CDCl3, 300 MHz) δ 7.93-7.90 (m, 2H), 7.62 (br s, 1H), 7.55-7.43 (m, 3H), 7.39 (d, J=1.8 Hz, 1H), 4.54 (s, 2H), 3.81 (t, J=5.4 Hz, 2H), 2.83 (t, J=5.7 Hz, 2H), 1.51 (s, 9H).

Provenance & Evidence