wt/vol

 

wt/vol

MW

moles

density

equivs.

yield

I

2.46 mL

56.06

0.0423

0.963

1.0

 

II

1.114 g

24.00

0.0464

 

1.1

 

III

5.20 mL

171.04

0.0437

1.438

1.0

 

IV

40 mL

-

-

 

 

 

V

6.166 g

146.18

0.0422

 

 

(100%)

 

Procedure:  100 mL 1-neck flask, stirbar, septum, N2 inlet

                  Prepared a suspension of 1.114 g of powdered NaH in 40 mL of dry THF.  Stirred; cooled to 0 C.  Added 2.46 mL of propargyl alcohol dropwise.  Hydrogen gas evolution occurred.  Stirred for 15 min.  Added 5.20 mL of BnBr.  and allowed the reaction mixture to slowly warm to rt.  After 24 h the reaction was quenched with sat. aq. NH4Cl and extracted with Et2O.  The organic layer was dried over MgSO4, filtered and the solvent was removed by rotary evaporation.  The product was isolated by Kugelrohr distillation (15 mm, 100 C) as a clear, colorless oil.

 

notes

 

This reaction is a simple SN2 substitution with in situ formed alkoxide displacing bromine.