Nitrogen → Chromanone

Participants

Reaction Steps

To a 10 mL CEM microwave test tube was charged with Cs2CO3 (391 mg, 1.20 mmol), PdCl2(PPh3)2 (30 mg, 0.04 mmol), (S/R)-6-bromo-2-((R/S)-tetrahydro-2H-pyran-3-yl)chroman-4-one (185.7 mg, 0.60 mmol), 3,5-difluorophenylboronic acid (142 mg, 0.90 mmol), dioxane (3 mL) and H2O (0.3 mL), the system was swept with N2 and capped, and heated in a CEM microwave reactor at 100 C for 8 min. Another tube charged with the same amount of reagents and starting material was repeated the same reaction at the same temperature and reaction time. Combined the reaction mixture and evaporated. The residue was dissolved in MeOH and filtered. The filtrate was evaporated and purified by flash chromatography on silica gel and eluted with EA in hexane (0-40%) to give (S/R)-6-(3,5-difluorophenyl)-2-(R/S)-tetrahydro-2H-pyran-3-yl)chroman-4-one (281 mg). 1H NMR (400 MHz, CDCl3) δ: 8.07 (s, 1H), 7.68 (dd, J=8.4, 2.0, 1H), 7.09-7.06 (m, 3H), 6.77 (m, 1H), 4.38 (m, 1H), 3.97-3.90 (m, 2H), 3.52-3.43 (m, 2H), 2.84-2.65 (m, 2H), 2.05 (m, 2H), 1.73-1.61 (m, 4H); 19F NMR (375 Hz, CDCl3) δ: −109.82; MS ESI+ve m/z 345 (M+H)+.

Provenance & Evidence