Reaktion #5805

Reaktionsgleichung

diethyl ether

t-butyl alcohol

(±)-cis-4-(cyanomethyl)-1,5-dioxaspiro[5.5]-undecane-2-acetic acid

dicyclohexylcarbodiimide

→

(±)-cis-1,1-dimethylethyl 4-(cyanomethyl)-1,5-dioxaspiro[5.5]undecane-2-acetate

Lösungsmittel

dichloromethane

dichloromethane

Reaktionsbedingungen

Aufarbeitung

1. 1
   Temperaturto slowly warm to room temperature over a 16.5-hour period
2. 2
   workup.STIRRINGThe mixture is stirred one hour
3. 3
   workup.STIRRINGstirring continued four hours
4. 4
   Filtrationfiltered
5. 5
   EinengenThe filtrate is concentrated at reduced pressure
6. 6
   EinengenThis crude concentrate
7. 7
   Sonstigeis chromatographed on silica gel
8. 8
   Wascheneluted with 4:1 hexane

Vorschrift

(±)-cis-4-(cyanomethyl)-1,5-dioxaspiro[5.5]-undecane-2-acetic acid 3.32 g (13.12 mmol), is dissolved in 15 mL of dichloromethane, cooled to 0° C. and 0.1 g of 4-dimethylaminopyridine (DMAP) added, followed y t-butyl alcohol, and followed by 3.25 g of dicyclohexylcarbodiimide (DCC). This solution is stirred and allowed to slowly warm to room temperature over a 16.5-hour period. TLC shows mainly product, and some slightly lower Rf by-product. The mixture is stirred one hour and 50 mL of dichloromethane is added and stirring continued four hours. One hundred mL of diethyl ether is added and then filtered. The filtrate is concentrated at reduced pressure. This crude concentrate is chromatographed on silica gel and eluted with 4:1 hexane:ethyl acetate to yield (±)-cis-1,1-dimethylethyl 4-(cyanomethyl)-1,5-dioxaspiro[5.5]undecane-2-acetate.

Quelle