Reaction Steps
An EtOAc (30 mL, sparged for 30 min with O2 directly prior to the reaction) slurry of cesium carbonate (12.76 g, 36.2 mmol, 4 equiv.), 31 (3.55 g, 9.04 mmol, 1 equiv.), and a nonane solution of tert-butyl hydroperoxide (5.5 M, 6.6 mL, 36 mmol, 4 equiv.) was cooled to −78° C. in a 3-neck 300-mL round-bottom flask with O2 bubbling through the slurry via glass pipette. An EtOAc (25 mL) solution of bis(trifluoroacetoxy)iodobenzene (11.67 g, 27.1 mmol, 3 equiv.) was added dropwise over 30 min, following by an EtOAc (5 mL) rinse of the flask that contained the bis(trifluoroacetoxy)iodobenzene. The slurry was stirred at −78° C. for 2 h and subsequently slowly warmed to 0° C. over 2.25 h. The resulting pink slurry was subsequently quenched at 0° C. with saturated aqueous Na2S2O3, O2 bubbling was suspended, and the resulting yellow mixture was stirred vigorously at room temperature for 45 min. The mixture was then extracted thrice with EtOAc. The organic extracts were combined, washed with H2O and brine, dried over Na2SO4, filtered, and concentrated in vacuo to a yellow oil. Flash column chromatography (300 mL SiO2, 7:3 hexane:EtOAc) afforded 1.07 g (2.63 mmol, 29% yield) of 32 as a viscous yellow syrup. TLC Rf 0.18 (1:1 hexane:EtOAc). 1H NMR (600 MHz; CDCl3): δ 5.33 (s, 1H), 5.29 (t, J=7.2 Hz, 1H), 3.90 (d, J=5.7 Hz, 1H), 3.70 (s, 3H), 3.46 (s, 3H), 3.12 (s, 3H), 2.67 (s, 1H), 2.41 (dd, J=15.0, 6.1 Hz, 1H), 2.34 (dd, J=14.9, 8.0 Hz, 1H), 2.00 (d, J=13.0 Hz, 1H), 1.93 (dd, J=13.1, 5.7 Hz, 1H), 1.69 (s, 3H), 1.62 (s, 3H), 1.39-1.29 (m, 4H), 1.26 (s, 3H), 1.23-1.11 (m, 2H), 1.09 (s, 6H). 13C NMR (126 MHz; CDCl3): δ 198.0, 181.3, 133.0, 122.1, 115.4, 100.8, 80.7, 74.5, 56.7, 56.4, 52.2, 49.3, 48.6, 48.1, 40.9, 38.8, 34.6, 32.1, 28.0, 26.3, 25.3, 25.0, 18.2, 17.9.
