Hydrochloric Acid → Bicyclo[2.2.1]hept-5-ene-2,3-diol

A 1-L round bottom flask was charged under nitrogen with 450 mL of tert-butanol, 30 mL pyridine, 92 g (1 mol) of norbornadiene, 257.4 g of a 50% aqueous solution of 4-methylmorpholine-N-oxide (Sigma-Aldrich Chemical Company, Milwaukee, Wis.) and 6 mL of a 4% aqueous solution of osmium tetroxide (Sigma-Aldrich Chemical Company). This mixture was heated at reflux overnight. The solution was cooled to room temperature and treated with 3 g of sodium hydrosulfite and 30 g of Florisil. The pH of the solution was adjusted to 7 by addition of aqueous HCl. The mixture was stirred and filtered through Celite. The filtrate was concentrated on a rotary evaporator to remove most of the organic solvents. The remaining solution was acidified to pH 1-2 and extracted with ether. The ether extracts were washed with saturated aqueous sodium chloride solution, dried over anhydrous magnesium sulfate and concentrated to give 65.3 g (52%) of the desired product as a white solid judged sufficiently pure for subsequent transformation. Another sample prepared by the same procedure had 1H-NMR (ppm, CDCl3, major isomer): δ 1.60 (1H, dp, J=9.5, 2.0 Hz), 1.87 (1H, d, J=9.0 Hz), 2.67 (2H, p, J=2.0 Hz), 3.68 (2H, d, J=2.0 Hz), 6.01 (2H, t, J=2.0 Hz). 13C—NMR (ppm, CDCl3, major isomer): δ 42.4, 48.2, 69.1, 136.6. (Exo/exo isomer to endolendo isomer ratio was 97:3 by 1H-NMR analysis.)

1. temperatureThis mixture was heated
2. temperatureat reflux overnight
3. filtrationfiltered through Celite
4. concentrationThe filtrate was concentrated on a rotary evaporator
5. customto remove most of the organic solvents
6. extractionextracted with ether
7. washThe ether extracts were washed with saturated aqueous sodium chloride solution
8. dry with materialdried over anhydrous magnesium sulfate
9. concentrationconcentrated

ORD record

ord-e8c066fbe35f48b196d35f6a4ecf26b4

Source dataset

uspto-grants-2009_03

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07507522B2