wt/vol

 

wt/vol

MW

moles

density

equivs.

yield

I

1.498 g

386.71

0.0039

 

1.0

 

II

1.0 mL

264.34

0.0044

1.151

1.1

 

III

0.50 mL

107.16

0.0043

0.920

1.1

 

IV

40 mL

-

-

 

 

 

V

1.711 g

500.97

0.0034

 

 

(88%)

 

Procedure:  250 mL 1-neck flask, stirbar, septum, N2 inlet

                  Dissolved 1.498 g of alcohol I in 40 mL of dry CH2Cl2.  Stirred; cooled to 0 C.  Added 0.50 mL of 2,6-lutidine followed by 1.0 mL of TBSOTf.  The bath was removed and the reaction was allowed to warm to rt.  After 30 min, TLC (5:95 EtOAc-hexanes, PMA) showed product spot at Rf 0.77.  The solvent was removed from the reaction mixture by rotary evaporation.  The product was isolated by flash chromatography on silica gel using 5:95 EtOAc-hexanes as eluant. The product was a clear, colorless oil. 

 

notes

 

TBSOTf is a more reactive silylating reagent than TBSCl.  Often when a hindered alcohol resists silylation with TBSCl, success can be achieved with TBSOTf/imidazole.