Dichloromethane → Cyclopentadienyl Acetaldehyde Diethylacetal

Temperature

25 °C

Sodium hydride (2.00 g, 60% wt. dispersion in mineral oil, 50.0 mmol) was washed with 40 mL hexanes. Hexanes were decanted and THF (35 mL) was added to the sodium hydride. A solution of 10 mL of freshly cracked cyclopentadiene in 10 mL of THF was slowly added dropwise, releasing heat and gas. This sodium cyclopentadienyl solution was added dropwise to a solution of bromoacetaldehyde diethylacetal (7.8 mL, 9.90 g, 50.0 mmol) in 45 mL THF to give a brown solution and light precipitate. After stirring overnight at 25° C., the mixture was filtered over Celite to remove sodium bromide, and solvent was removed from the filtrate in vacuo to give to a brown oil. To this was added 50 mL of dichloromethane and the mixture was again filtered through Celite. Solvent was removed in vacuo leaving a brown oil. 1H NMR data suggests a 1:1 mixture of 1,2- and 1,3-isomers. 1H NMR (CDCl3, 600 MHz): δ 6.50 (m, 1H), 6.43 (m, 1H), 6.40 (m, 1H), 6.29 (m, 1H), 6.27 (m, 1H), 6.14 (m, 1H), 4.66 (t, 1H), 4.61 (t, 1H), 3.67 (m, 4H), 3.51 (m, 4H), 2.96 (m, 2H), 2.75 (d, 1H), 2.72 (d, 1H) 1.21 (t, 12H). 13C{1H} NMR (CDCl3, 150.8 MHz): 144.16 (s), 142.05 (s), 135.01 (s), 133.47 (s), 132.30 (s), 131.54 (s), 128.68 (s), 128.51 (s), 102.72 (s), 102.52 (s), 61.26 (s), 61.08 (s), 44.07 (s), 41.33 (s), 35.24 (s), 34.62 (s), 15.30 (s).

1. customHexanes were decanted
2. additionTHF (35 mL) was added to the sodium hydride
3. additionA solution of 10 mL of freshly cracked cyclopentadiene in 10 mL of THF was slowly added dropwise
4. temperaturereleasing heat
5. customto give a brown solution and light precipitate
6. filtrationthe mixture was filtered over Celite
7. customto remove sodium bromide, and solvent
8. customwas removed from the filtrate in vacuo
9. customto give to a brown oil
10. filtrationthe mixture was again filtered through Celite
11. customSolvent was removed in vacuo
12. customleaving a brown oil
13. additiona 1:1 mixture of 1,2- and 1,3-isomers

ORD record

ord-33ef6e9283d94da48101aad45ca1f317

Source dataset

uspto-grants-2013_09

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08524846B1