Реакция #2659

Уравнение реакции

trityl chloride

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

4-hydroxy-2-cyclopentenone

→

title compound

Выход 37.0%

4-trityloxy-2-cyclopentenone

Выход 37.0%

Растворители

methylene chloride

Условия реакции

Обработка

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

Методика

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.

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