Triethylborane → HCID 13476231, compound

Participants

Reaction Conditions

Reaction Steps

Into a glass vessel under nitrogen was charged tetrahydrofuran (22 ml), methyl E-7-(4'-fluoro-3,3',5-trimethyl[1,1'-biphenyl]-2-yl)-5-hydroxy-3-oxo-6-heptenoate (3.0 g, 7.8 mmole) and triethylborane (0.92 g, 9.4 mmole) at ambient temperature and air was bubbled through the solution. After a 5 minute age, the solution was cooled to -78° C. Sodium borohydride (350 mg, 9.25 mmole) was added followed by the addition over 15 minutes of methanol (5 ml) maintaining a temperature below -65° C. After a 30 minute age at -78° C. the mixture is carefully quenched into a rapidly stirred solution of 30% hydrogen peroxide (15 ml) and water (30 ml) at 20° C., aged 30 min then extracted with 50 ml of ethyl acetate. The organic extract was washed successively with 1N aqueous hydrochloric acid (25 ml), water (25 ml) and pH 7 buffer (25 ml), then dried over sodium sulfate (25 g). After filtration, the solution was concentrated to an oil in vacuo. Crystallization was induced by flushing with hexane, and reconcentrating in vacuo to yield the title compound in 90% assay yield (2.71 g). The product was triturated with hexanes to yield a white solid, mp. 78°-80° C. (dec). HPLC assay indicated a purity of 99%.

Provenance & Evidence