Reaktion #2659

Reaktionsgleichung

trityl chloride

1,8-diazabicyclo[5.4.0]undec-7-ene

4-hydroxy-2-cyclopentenone

→

title compound

Ausbeute 37.0%

4-trityloxy-2-cyclopentenone

Ausbeute 37.0%

Lösungsmittel

methylene chloride

Reaktionsbedingungen

Aufarbeitung

1. 1
   workup.ADDITIONpoured onto ice (approximately 25 mL)
2. 2
   SonstigeThe phases are separated
3. 3
   Waschenthe organic phase is washed with water (25 mL)
4. 4
   TrocknenThe organic phase is dried over anhydrous magnesium sulfate
5. 5
   Filtrationfiltered
6. 6
   Einengenconcentrated under vacuum
7. 7
   SonstigeThe residue is purified by column chromatography (silica gel, 10-20% ethyl acetate/hexane)

Vorschrift

A solution of trityl chloride (3.44 g, 12.3 mmol) in methylene chloride (20 mL) is treated sequentially with 1,8-diazabicyclo[5.4.0]undec-7-ene (2.2 mL, 14.7 mmol, DBU) and 4-hydroxy-2-cyclopentenone (1.01 g, 10.0 mmol, in 5 mL of methylene chloride, prepared in example 1). The reaction is stirred for 3 days at room temperature and then poured onto ice (approximately 25 mL). The phases are separated and the organic phase is washed with water (25 mL). The organic phase is dried over anhydrous magnesium sulfate, filtered and concentrated under vacuum. The residue is purified by column chromatography (silica gel, 10-20% ethyl acetate/hexane) to provide the title compound (1.26 g, 36%) as a pale yellow oil; 1H NMR (CDCl3) δ7.5 (m, 6H), 7.3 (m, 9H), 6.85 (dd, 1H), 6.05 (d, 1H), 4.8 (m, 1H), 2.1 (m, 2H); 13C NMR (CDCl3) δ206.6, 162.9, 144.3, 135.2, 128.8, 128.4, 127.7, 88.2, 73.1, 43.4; IR (KBr) νmax 3061, 1719, 1491, 1449, 1352, 1181, 1107, 1053 cm-1.

Quelle