Tetrahydrofuran → 2-Octen-4-one, 2-methyl-

To a magnetically stirred and ice-cooled solution of N-methoxy-N-methyl-acrylamide (20 gram, 132.7 mmol) in anhydrous tetrahydrofuran (200 ml) in a nitrogen atmosphere was slowly added n-butylmagnesium chloride (132.7 ml, 2 M solution in diethyl ether, 265 mmol) and the resulting mixture was stirred for 30 minutes. The resulting mixture was allowed to attain room temperature and stirred for 40 hours. An aqueous ammonium chloride solution (15 gram dissolved in 100 ml water) was slowly added, followed by addition of ethyl acetate (100 ml). The organic layer was separated, washed with brine, dried over MgSO4, filtered and concentrated in vacuo to give crude 2-methyl-oct-2-en-4-one. Sepacore (80×150 mm column) separation (eluant: petroleum ether (40-60)/diethyl ether=95/5 (v/v)) gave 2-methyl-oct-2-en-4-one (Intermediate IIIb-1) as a colorless oil (9.30 gram, 47% yield). 1H-NMR (400 MHz, CDCl3) δ 0.91 (t, J=7.2 Hz, 3H), 1.27-1.38 (M, 2H), 1.52-1.62 (m, 2H), 1.89 (s, 3H), 2.14 (s, 3H), 2.39 (t, J=7.4 Hz, 2H), 6.08 (br s, 1H).

1. stirringthe resulting mixture was stirred for 30 minutes
2. customto attain room temperature
3. stirringstirred for 40 hours
4. customThe organic layer was separated
5. washwashed with brine
6. dry with materialdried over MgSO4
7. filtrationfiltered
8. concentrationconcentrated in vacuo
9. customto give crude 2-methyl-oct-2-en-4-one
10. customSepacore (80×150 mm column) separation (eluant: petroleum ether (40-60)/diethyl ether=95/5 (v/v))

ORD record

ord-a600459e945345e28a8fcc3f5a356609

Source dataset

uspto-grants-2013_04

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08410135B2