Cyclopentadiene → 5-Fluoro-1,4-dihydro-1,4-methanonaphthalene

A solution of 2,6-difluoroiodobenzene (5.0 g, 20.8 mmol) and cyclopentadiene (2.07 g, 31.3 mmol) was stirred at 0° C. in P. ether (70 mL, 40-60° C.) under N2 and treated with n-BuLi (8.74 mL, 2.5M in hexanes, 21.8 mmol) dropwise over 10 minutes. The reaction was quenched after 15 minutes by addition of aqueous 1N HCl solution and the product was extracted with hexanes (3×50 mL). The combined organic layer was washed with H2O (50 mL), saturated aqueous NaCl solution (50 mL), dried (MgSO4), filtered and evaporated Chromatography on Silica gel provided product as an oil (1.5 g, 45%) (TLC hexanes Rf 0.55). 1H NMR (400 MHz, CDCl3) δ 7 08 (ddd, J=7 0, 1.0, 0.8 Hz, 1H), 6.96 (ddd, J=8.5, 8.3, 7 0 Hz, 1H), 6.86 (br s, 2H), 6.72 (ddd, J=8.5, 8.3, 0.8 Hz, 1H), 4.25 (br s, 1 H), 3.98 (br s, 1H), 2.36 (ddd, J=7.2, 1.7, 1.7 Hz, 1H), 2.30 (ddd, J=7 2, 1.7, 1.5 Hz, 1H). GCMS m/e 160 (M+).

1. customThe reaction was quenched after 15 minutes by addition of aqueous 1N HCl solution
2. extractionthe product was extracted with hexanes (3×50 mL)
3. washThe combined organic layer was washed with H2O (50 mL), saturated aqueous NaCl solution (50 mL)
4. dry with materialdried (MgSO4)
5. filtrationfiltered
6. customevaporated Chromatography on Silica gel provided product as an oil (1.5 g, 45%) (TLC hexanes Rf 0.55)

ORD record

ord-2dfe21d739ea4474b1720c8d33b0d597

Source dataset

uspto-grants-2005_10

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06951938B2