Reaction #2660

Reaction equation

4-trityloxy-2-cyclopentenone

lithium aluminum hydride

lithium iodide

tert-butyl methyl ether

→

title compound

Yield 95.0%

(+/-)-cis-4-trityloxy-2-cyclopentenol

Yield 95.0%

Solvents

toluene

Conditions

Workup

1. 1
   Temperaturewarmed to 0° C. over 30 minutes
2. 2
   workup.STIRRINGstirred at 0° C. to 15° C. for 4 hours
3. 3
   OtherThe reaction is quenched by slow addition of 1N NaOH (2 mL)
4. 4
   Filtrationthe reaction is filtered
5. 5
   WashThe solids are washed with tert-butyl methyl ether
6. 6
   Otherthe phases of the filtrate are separated
7. 7
   DryingThe organic phase is dried over anhydrous magnesium sulfate
8. 8
   Filtrationfiltered
9. 9
   Concentrationconcentrated under vacuum
10. 10
    OtherThe residue is purified by column chromatography (silica gel, 20% ethyl acetate/hexane)

Procedure

A slurry of 4-trityloxy-2-cyclopentenone (1.03 g, 3.03 mmol, prepared in example 27) in toluene (8 mL) is cooled to -20° C. and treated sequentially with lithium aluminum hydride (76 mg, 2.0 mL), lithium iodide (1.06 g, 7.9 mmol) and dropwise with tert-butyl methyl ether (2 mL, over 5 minutes). The reaction is stirred for 1 hour at -20° C., warmed to 0° C. over 30 minutes, and stirred at 0° C. to 15° C. for 4 hours. The reaction is quenched by slow addition of 1N NaOH (2 mL) and then the reaction is filtered. The solids are washed with tert-butyl methyl ether and the phases of the filtrate are separated. The organic phase is dried over anhydrous magnesium sulfate, filtered and concentrated under vacuum. The residue is purified by column chromatography (silica gel, 20% ethyl acetate/hexane) to provide the title compound as a white foam (980 mg, 95%). 1H NMR (CDCl3) δ7.5 (m, 6H), 7.3 (m, 9H), 5.79 (d, 1H), 5.14 (d, 1H), 4.5 (m, 1H), 4.4 (m, 1H), 2.2 (m, 1H), 1.42 (d, 1H); 13C NMR (CDCl3) δ145.1, 136.2, 135.9, 129.0, 128.1, 127.3, 87.7, 77.4, 74.9, 43.2; IR (KBr) νmax 3422, 3057, 1491, 1364, 1084, 1065, 1024 cm-1.

Source