Borane;tetrahydrofuran → (R)-2-Bromo-1-(2,2-dimethyl4H-benzo[1,3]dioxin-6-yl)ethanol

To the product of step (c) (10 g, 35.1 mmol) in 100 mL of THF was added the solid catalyst of Preparation 13, step (c)(1) (0.97 g, 3.5 mmol). The solution was cooled to between −20° C. and −10° C. and BH3-THF (35 mL, 35 mmol) diluted with 50 mL THF was added dropwise via a dropping funnel. After the addition was complete, the reaction mixture was allowed to warm to ambient temperature. After 30 minutes, the reaction mixture was quenched by slow addition of 50 mL of methanol and then concentrated to a thick oil. The oil was purified by silica gel chromatography eluted with 1:2 ethyl acetate/hexanes. The fractions were combined and concentrated to give the title compound as an off-white solid.

1. customthe solid catalyst of Preparation 13, step (c)(1) (0.97 g, 3.5 mmol)
2. temperatureThe solution was cooled to between −20° C. and −10° C.
3. additionwas added dropwise via a dropping funnel
4. additionAfter the addition
5. customthe reaction mixture was quenched by slow addition of 50 mL of methanol
6. concentrationconcentrated to a thick oil
7. customThe oil was purified by silica gel chromatography
8. washeluted with 1:2 ethyl acetate/hexanes
9. concentrationconcentrated

ORD record

ord-87d8fb1ca4904847ac02eb72def5ea83

Source dataset

uspto-grants-2009_04

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07521561B2