تفاعل #2634

معادلة التفاعل

4-hydroxy-2-cyclopentenone

triethylamine

tert-butyldimethylsilyl chloride

→

title compound

المردود 83.2%

4-tert-butyldimethylsiloxy-2-cyclopentenone

المردود 83.2%

المذيبات

HCl

tetrahydrofuran

tetrahydrofuran

ظروف التفاعل

المعالجة

1. 1
   درجة الحرارةmaintaining the temperature at or below 10° C
2. 2
   أخرىThe phases are separated
3. 3
   استخلاصthe aqueous phase is extracted with heptane (2×1L)
4. 4
   غسيلwashed with aqueous HCl (0.5N, 2×500 mL)
5. 5
   تجفيف5% sodium bicarbonate (500 mL), then brine (500 mL), dried over anhydrous magnesium sulfate
6. 6
   ترشيحfiltered
7. 7
   تركيزconcentrated under vacuum (40° C., 20 mmHg)

الإجراء التجريبي

A solution of 4-hydroxy-2-cyclopentenone (191 g, 1.95 mol, prepared in example 1) and triethylamine (430 mL, 3.09 mol) in anhydrous tetrahydrofuran (1L) is treated with 4-dimethylaminopyridine (4.90 g, 40.0 mmol). The solution is cooled to 0° C. and treated portionwise, over 10 minutes, with tert-butyldimethylsilyl chloride (278 g, 1.84 mol) maintaining the temperature at or below 10° C. The reaction is then allowed to stir overnight at room temperature. It is then poured into aqueous HCl (0.5N, 1L). The phases are separated and the aqueous phase is extracted with heptane (2×1L). The organic phase and organic extracts are combined, washed with aqueous HCl (0.5N, 2×500 mL), then 5% sodium bicarbonate (500 mL), then brine (500 mL), dried over anhydrous magnesium sulfate, filtered and concentrated under vacuum (40° C., 20 mmHg) to provide the title compound (325 g). This is purified by Kugelrohr distillation (70°-80° C., 1 mmHg) to provide the title compound (282 g, 72% yield) as a light yellow oil, Rf =0.55, 20% ethyl acetate/hexane, GC retention time is 14.97 minutes; 1H NMR (CDCl3) δ7.48 (dd, J=5.7, 2.4 Hz, 1H), 6.20 (d, J=5.7 Hz, 1H), 4.95-4.99 (m, 1H), 2.72 (dd, J=18.2, 6.0 Hz, 1H), 2.25 (dd, J=18.2, 2.3 Hz, 1H), 0.88 (s, 9H), 0.11 (s, 6H); 13C NMR (CDCl3) δ 206.4, 163.8, 134.4, 70.8, 44.9, 25.7, 25.6, 18.0; IR (neat) νmax 2957, 2931, 2887, 2858, 1725 cm-1 ; MS (EI) m/e (% relative intensity) 212 (M+, 5), 155 (M+ -57,100).

المصدر