tert-Butyl hydroperoxide → [(1S,3S,5S)-3-(Tritylamino)-6-oxabicyclo[3.1.0]hexan-1-yl]methanol

Participants

Reaction Conditions

Reaction Steps

A reactor was charged with (+)-diethyl-L-tartrate (2.23 L, 13.0 mol) and methylene chloride (10.5 L). Stirring was started and the mixture was cooled to −30 to −40° C. Titanium (IV) isopropoxide (3.93 L, 13.4 mol) was slowly added while maintaining the internal temperature between −30 to −40° C. A solution of [(4S)-4-(tritylamino)cyclopent-1-en-1-yl]methanol (4.2 kg, 11.8 mol) in methylene chloride (19 L) was slowly added to the reaction mixture, while maintaining the temperature between −30 to −40° C. After stirring for 20 minutes, t-butyl hydroperoxide (5-6 M in decane, 3.3 L, 16.3 mol) was slowly added while maintaining the temperature between −30 to −40° C. Upon completion of the addition, the reaction mixture was analyzed by HPLC, which confirmed the formation of the product and presence of 3% (AUC) of the starting material. The reaction mixture was carefully quenched into a 100-L reactor containing a cold aqueous solution (0 to 5° C.) of iron (II) sulfate heptahydrate (10.5 kg) and tartaric acid (6.3 kg) in DI water (42 L). After stirring for 15 minutes, the organic phase was separated and filtered through a pad of diatomaceous earth. The pad was washed with methylene chloride (2×2 L), and the filtrate was transferred into a 100-L reactor. A cold solution (0 to 5° C.) of solid sodium hydroxide (3.36 kg) in brine (42 L) was slowly added to the gently stirred reaction mixture. After 1 h, the organic phase was separated, dried over anhydrous sodium sulfate, filtered through a pad of diatomaceous earth and concentrated under reduced pressure to give a brown oil. This was purified via silica-gel chromatography using five columns. Each column was performed as follows. A 20 cm diameter glass column was loaded with a slurry of silica gel (5 kg) in 30% ethyl acetate/heptane with 0.5% triethylamine added. Crude product (˜1.2 kg) was adsorbed onto silica gel (1.5 kg) and loaded on the column. Polarity was gradually increased from 30% to 40% ethyl acetate/heptane with 0.5% triethylamine. Combined purified material from all columns afforded the title compound (3.93 kg, 89% yield) as an amber oil. 1H NMR (300 MHz, CDCl3, δ) 7.54-7.50 (m, 5H), 7.32-7.18 (m, 10H), 3.80-3.76 (d, J=12.5 Hz, 1H), 3.65-3.61 (d, J=12.5 Hz, 1H), 3.31 (s, 1H), 3.03-2.92 (m, 1H), 1.77-1.69 (m, 2H) and 1.37-1.13 (m, 2H).

Provenance & Evidence