Tert buooh

The synthesis of taxadien-5α-ol (2) is adapted from a previously described method^{30 (link)}. Tert-BuOOH (21.3 μL of 98% purity, 0.114 mmol; Sigma–Aldrich) was added to a solution of SeO₂ (3.3 mg, 0.030 mmol; Strem) in CH₂Cl₂ (50 μL; Sigma–Aldrich) and stirred for 0.5 h. Subsequently, purified taxadiene (1) (15.5 mg, 0.0570 mmol) in CH₂Cl₂ (200 μL) was added to the solution and allowed to stir for 2.5 h at room temperature. The resulting yellow solution was concentrated on a rotary evaporator under reduced pressure to yield yellow crude oil. Flash chromatography was carried out using a 2 mL glass Pasteur pipette loaded with 200 mg of P60 silica gel (SiliCycle) with hexane (HPLC grade; VWR) as the initial mobile phase. The column was first eluded with 100% hexane to yield unreacted 1 (21% recovery), then with hexane-diethyl ether (Fischer Chemical) in a ratio of 5:1 to yield 2.3 mg of an over-oxidized ketone product (TLC R_f = 0.63 when eluded with hexane-Et₂O 5:1 and stained with KMnO₄; 14% isolated yield) and 1.8 mg of 2 (TLC R_f = 0.36 when eluded with hexane-Et₂O 5:1 and stained with KMnO₄; 11% isolated yield). Fractions were collected in 200 μL volume. The ¹H NMR data of synthetic taxadien-5α-ol (2) are reported and compared to 2 heterologously produced in E. coli to confirm its identity (Supplementary Figs. 14–15).