Reacción #2634

Ecuación de reacción

4-hydroxy-2-cyclopentenone

triethylamine

tert-butyldimethylsilyl chloride

→

title compound

Rendimiento 83.2%

4-tert-butyldimethylsiloxy-2-cyclopentenone

Rendimiento 83.2%

Disolventes

HCl

tetrahydrofuran

tetrahydrofuran

Condiciones de reacción

Tratamiento posterior

1. 1
   Temperaturamaintaining the temperature at or below 10° C
2. 2
   OtroThe phases are separated
3. 3
   Extracciónthe aqueous phase is extracted with heptane (2×1L)
4. 4
   Lavadowashed with aqueous HCl (0.5N, 2×500 mL)
5. 5
   Secado5% sodium bicarbonate (500 mL), then brine (500 mL), dried over anhydrous magnesium sulfate
6. 6
   Filtraciónfiltered
7. 7
   Concentraciónconcentrated under vacuum (40° C., 20 mmHg)

Procedimiento

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).

Fuente