Reaction #498345

Reaction equation

tert-butyl 9-oxa-3,7-diazabicyclo[3.3.1]nonane-3-carboxylate hydrochloride

K2CO3

1-chloropinacolone

→

sub-title compound

Yield 85.5%

tert-Butyl 7-(3,3-dimethyl-2-oxobutyl)-9-oxa-3,7-diazabicyclo[3.3.1]nonane-3-carboxylate

Yield 85.5%

Solvents

MeCN

Conditions

Workup

1. 1
   OtherPreparation A
2. 2
   TemperatureThe following morning, the temperature was raised to 50° C. for 4 h before the solids
3. 3
   Filtrationwere filtered off from the mixture
4. 4
   Concentrationthe filtrate concentrated in vacuo
5. 5
   workup.DISSOLUTIONThe crude product was dissolved in DCM
6. 6
   workup.ADDITIONthe solution was added to an ion-exchange solid phase extraction plug (10 g CBA (carboxylic acid on silica support))
7. 7
   workup.WAITAfter 1 h
8. 8
   Washthe plug was washed with DCM (15 mL)
9. 9
   Washafter which the product was finally eluted with dichloromethane:MeOH:TEA (90:5:5)
10. 10
    OtherThe solvents were evaporated

Procedure

A mixture of tert-butyl 9-oxa-3,7-diazabicyclo[3.3.1]nonane-3-carboxylate hydrochloride (Preparation A; 0.26 g, 1.0 mmol) and K2CO3 (1.45 g, 10.5 mmol) in MeCN (8 mL) was treated with 1-chloropinacolone (0.216 g, 1.6 mmol), and the mixture stirred at 40° C. overnight. The following morning, the temperature was raised to 50° C. for 4 h before the solids were filtered off from the mixture and the filtrate concentrated in vacuo. The crude product was dissolved in DCM and the solution was added to an ion-exchange solid phase extraction plug (10 g CBA (carboxylic acid on silica support)). After 1 h, the plug was washed with DCM (15 mL), after which the product was finally eluted with dichloromethane:MeOH:TEA (90:5:5). The solvents were evaporated to give 0.276 g (85.5%) of the sub-title compound.

Source