Lithium Hexamethyldisilazide → (S)-7-(2-fluoropyridin-3-yl)-3-((R)-3-fluoropyrrolidin-1-yl)-2',6'-dihydrospiro[chromeno [2,3-b]pyridine-5,3'-[1,4]oxazin]-5'-amine

Participants

Reaction Steps

A vial was charged with 2-fluoropyridin-3-ylboronic acid (0.094 g, 0.667 mmol), PdCl2(dppf)-CH2Cl2-adduct (0.026 g, 0.032 mmol), (S)-3-bromo-7-iodo-2′,6′-dihydrospiro[chromeno[2,3-b]pyridine-5,3′-[1,4]oxazin]-5′-amine (0.300 g, 0.635 mmol), and potassium carbonate (0.351 g, 2.54 mmol). Dioxane (3.5 mL) and water (1.5 mL) were added. The vial was flushed with argon, sealed and heated to 80° C. for 1 hour. The reaction mixture was then diluted with EtOAc, dried over MgSO4 and concentrated. Purification of the crude residue by column chromatography [0-80% (90:10:1 DCM/MeOH/NH4OH)/DCM] gave (S)-3-bromo-7-(2-fluoropyridin-3-yl)-2′,6′-dihydrospiro[chromeno[2,3-b]pyridine-5,3′-[1,4]oxazin]-5′-amine (0.202 g, 0.458 mmol) Step 2: A vial was charged with (R)-3-fluoropyrrolidine HCl (0.021 g, 0.170 mmol), (S)-3-bromo-7-(2-fluoropyridin-3-yl)-2′,6′-dihydrospiro[chromeno[2,3-b]pyridine-5,3′-[1,4]oxazin]-5′-amine (0.050 g, 0.113 mmol) and RuPhos palladacycle (9.05 mg, 0.011 mmol). THF (1 mL) and LiHMDS (1N in THF; 0.567 mL, 0.567 mmol) were added, and the reaction mixture was allowed to stir at RT overnight. Additional RuPhos palladacycle (9.05 mg, 0.011 mmol) and LiHMDS solution (0.567 mL, 0.567 mmol) were added, and the reaction mixture was heated to 45° C. for 2 hours. The reaction mixture was then quenched with MeOH and concentrated under reduced pressure. Purification of the crude residue by column chromatography [0-100% (90:10:1 DCM/MeOH/NH4OH)/DCM] gave (S)-7-(2-fluoropyridin-3-yl)-3-((R)-3-fluoropyrrolidin-1-yl)-2′,6′-dihydrospiro[chromeno[2,3-b]pyridine-5,3′-[1,4]oxazin]-5′-amine (0.018 g, 0.040 mmol, 35.3% yield).

Provenance & Evidence