Reacción #2659

Ecuación de reacción

trityl chloride

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

4-hydroxy-2-cyclopentenone

→

title compound

Rendimiento 37.0%

4-trityloxy-2-cyclopentenone

Rendimiento 37.0%

Disolventes

methylene chloride

Condiciones de reacción

Tratamiento posterior

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

Procedimiento

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.

Fuente