Reacción #2657

Ecuación de reacción

(-)-cis-4-tert-butyldimethylsilyloxy-2-cyclopentenol

sodium borohydride

→

title compound

Rendimiento 87.3%

(-)-cis-3-tert-butyldimethylsilyloxycyclopentanol

Rendimiento 87.3%

Disolventes

ethanol

Condiciones de reacción

Tratamiento posterior

1. 1
   Lavadopreviously washed with water (2×50 mL) and ethanol (2×50 mL))
2. 2
   workup.ADDITIONCharge the atmosphere with hydrogen at 50 psi (344.74 kPa) and shake the mixture
3. 3
   Filtraciónfilter
4. 4
   Otrothe reaction
5. 5
   Concentraciónconcentrate the solution under vacuum
6. 6
   workup.DISTILLATIONdistill the resulting oil
7. 7
   workup.DISTILLATIONby Kugelrohr distillation (40°-60° C., 1 mmHg)

Procedimiento

Dissolve (-)-cis-4-tert-butyldimethylsilyloxy-2-cyclopentenol (28.85 g, 135 mmol, prepared in example 10) in ethanol (75 mL) and treated with Raney nickel (1.85 g, 32 mmol, previously washed with water (2×50 mL) and ethanol (2×50 mL)). Charge the atmosphere with hydrogen at 50 psi (344.74 kPa) and shake the mixture. After 5.25 hours, filter the reaction. Cool the filtrate to 0° C. and treat with sodium borohydride (0.54 g, 14.3 mmol). After stirring for 2 hours, concentrate the solution under vacuum and distill the resulting oil by Kugelrohr distillation (40°-60° C., 1 mmHg) to provide the title compound (25.5 g, 87%) as a colorless oil, [α]20 =-3.9°, (c=0.99, chloroform); 1H NMR (CDCl3) δ4.4 (m, 1H), 4.3 (m, 1H), 3.03 (d, 1H, J=10.5 Hz), 1.9-1.6 (m, 6H), 0.89 (s, 9H), 0.07 (s, 6H); 13C NMR (CDCl3) δ74.9, 74.1, 44.4, 34.2, 34.1, 25.8, 17.9, -4.9, -5.0; IR (neat) νmax 3405, 2957, 2932, 2888, 2858, 1256, 1091, 1069, 1038, 1026 cm-1 ; CIMS m/e (% relative intensity) 217 (M+H+ 81), 199 (M+H+ --H2O, 37) 67 (100). This (-)-enantiomer (title compound) could not be separated from the (+)-enantiomer (antipode) using the previously described chiral column.

Fuente