Tetrahydrofuran → 3-(dihydro-2H-pyran-3(4H)-ylidene)propan-1-ol
Reaction equation
[PH4+].[Li]CCCC.[O:7]1[CH2:12][CH2:11][CH2:10][C:9](=O)[CH2:8]1.[CH2:14]1C[O:17][CH2:16][CH2:15]1>>[O:7]1[CH2:12][CH2:11][CH2:10][C:9](=[CH:14][CH2:15][CH2:16][OH:17])[CH2:8]1Participants
5
Procedure
To a suspension of the phosphonium salt (69 g, 1.5 eg) in dry THF (1100 mL) at 0° C. under nitrogen atmosphere was added n-BuLi (2.5 M, 111 mL, 0.413 mol). The solution was stirred for 1 hr, followed by addition of dihydro-2H-pyran-3(4H)-one (11.5 g, 0.115 mol). Stirring was continued at rt overnight. The mixture was quenched by sat. aq. NH4Cl, and then filtered. The filtrate was dried over Na2SO4, and concentrated in vacuo to give the crude product, which was purified through column chromatography to give 3-(dihydro-2H-pyran-3(4H)-ylidene)propan-1-ol (11.2 g, 69%). 1H NMR (CD3OD): δ 4.2-3.9 (d, 2H), 3.8-3.5 (m, 4H), 2.4-2.2 (m, 4H), 5.3-5.2 (d, 1H), 2.1-1.8 (s, 1H), 1.8-1.6 (m, 2H).