Reaktion #1272201

Reaktionsgleichung

101d

5-tert-Butyl-2-(4,4-dimethyl-4,5-dihydro-oxazol-2-yl)-benzaldehyde

pyridinium p-toluenesulfonate

1,3-propanediol

→

101e

Ausbeute 21.7%

2-(4-tert-Butyl-2-1,3-dioxinan-2-yl-phenyl)-4,4-dimethyl-4,5-dihydrooxazole

Ausbeute 21.7%

Lösungsmittel

toluene

Reaktionsbedingungen

Aufarbeitung

1. 1
   Temperaturwas heated
2. 2
   Temperaturto reflux overnight
3. 3
   WaschenThe reaction mixture was washed with 200 mL of 50 percent aqueous NaHCO3, 200 mL of water, and 200 mL of brine
4. 4
   TrocknenThe organic layer was dried over Na2SO4
5. 5
   Filtrationfiltered
6. 6
   Einengenconcentrated in vacuo
7. 7
   Sonstigeto give a residue which
8. 8
   Sonstigewas purified by silica gel chromatography

Vorschrift

A mixture of 101d (60 g, 0.23 mol), pyridinium p-toluenesulfonate (4 g, 0.02 mol) and 1,3-propanediol (60 mL) in toluene (500 mL) was heated to reflux overnight and cooled to room temperature upon the completion of reaction determined by LCMS. The reaction mixture was washed with 200 mL of 50 percent aqueous NaHCO3, 200 mL of water, and 200 mL of brine. The organic layer was dried over Na2SO4, filtered and concentrated in vacuo to give a residue which was purified by silica gel chromatography using EtOAc/petroleum ether=1:5 as eluent to provide 101e (16 g, 21.7%) as a clear yellow gum. LCMS (ESI) 318 (M+H)+. 1HNMR (300 MHz, CDCl3) δ 7.79 (s, 1H), 7.67 (d, J=8.0 Hz, 1H), 7.36 (dd, J=1.6, 8.4 Hz, 1H), 6.32 (s, 1H), 4.23 (dd, J=5.2, 11.2 Hz, 2H), 4.06 (s, 2H), 4.04-3.98 (m, 2H), 2.27-2.21 (m, 1H), 1.48-1.38 (m, 1H), 1.38 (s, 6H), 1.32 (s, 9H).

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