Reaction #2662

Reaction equation

(+/-)-cis-3-tert-butyldimethylsilyloxycyclopentanol

triethylamine

vinyl acetate

→

(1R,3S)-(+)-3-tert-butyldimethylsilyloxycyclopentanyl acetate

Yield 49.0%

Solvents

tert-butyl methyl ether

Conditions

Workup

1. 1
   FiltrationThen filter
2. 2
   Otherthe reaction through diatomaceous earth
3. 3
   Concentrationconcentrate the filtrate under vacuum (room temperature/15 mmHg)
4. 4
   OtherPurify the residue by column chromatography [silica gel, 55 g, hexane (300 mL) followed by 5% ethyl acetate/hexane (500 mL)]

Procedure

Combine (+/-)-cis-3-tert-butyldimethylsilyloxycyclopentanol (2.119 g, 9.8 mmol, prepared in example 29), pancreatin (6.2 g, 3 weight equivalents), triethylamine (0.9 mL, 6.5 mmol) and vinyl acetate (4.3 mL) in tert-butyl methyl ether (12 mL) and stir for 27 hours at room temperature. Then filter the reaction through diatomaceous earth and concentrate the filtrate under vacuum (room temperature/15 mmHg). Purify the residue by column chromatography [silica gel, 55 g, hexane (300 mL) followed by 5% ethyl acetate/hexane (500 mL)] to provide the (1R,3S)-(+)-3-tert-butyldimethylsilyloxycyclopentanyl acetate (1.23 g, 49% yield, 98% ee as determined from gas chromatography with a chiral column) and (1S,3R)-(-)-3-tert-butyldimethylsilyloxycyclopentanol (771 mg, 37% yield, 92% ee as determined from its acetate derivative followed by GC chiral column analysis, see example 30a).

Source