PREPARATION OF CYCLOPROPANE DERIVATIVE


 

PREPARATION OF CYCLOPROPANE DERIVATIVE

Using NaH and Pd(0)


 

 

F SM/Reagent

F Eq

F Apparatus

CyanomethylImine (FW: 220.27)

1.0

1 Neck flask

1,4-Dibromo-2-butene (FW: 213.91)

1.0

Stirrrer

NaH (FW: 24, 60% in mineral oil)

2.0

 

Pd(Oac)2 (FW: 224.49)

0.017

 

PhP3 (FW: 262.29

0.033

 

THF (Anhy)

5ml/1mmol SM


 


Procedure

1.    Dissolve Imine and butene in THF.  Stir (N2)

2.    Add Pd(OAc)2 and Ph3P (as neat to form Pd(0)) [1]

3.    Stir the mixture at R.T. for 30 min

4.    Add slowly and portionally NaH (60% in mineral oil) over 45 min [2]

5.    Stir the reaction mixture at R.T for 1 hr [3]

6.    Quench reaction w/ ice cold water and dilute w/ EtOAc

7.    Filter thru Celite [4].   Wash filtrate w/water and brine

8.    Dry organic layer w/ MgSO4.  Filter

9.    Concentrate in vacuo ® crude as brownish oil

10.           Chromatograph w/ 0% ® 5% EtOAc/Hex [5]

11.           NMR w/ CDCl3.  Yield 70% as yellow oil [6]



G Notes:

[1]   Color change from light to darker yellowish solution

[2]  Slow addition of NaH is very important.  Gas ­ , color change from yellow to green then brownish

[3]  Follow reaction by TLC w/10% EtOAc/Hex

[4]  Wash Celite pad w/EtOAc

[5]  Dissolve the crude in Et2O

[6]  10% of Didebromination may obtain

Synlett 1996, November, p1067