wt/vol

 

wt/vol

MW/conc.

moles

density

equivs.

yield

I

1.027 g

114.18

0.0090

 

1.0

 

II

0.315 g

234.25

0.0013

 

0.15

 

III

0.250 g

284.26

0.0009

 

0.1

 

IV

3.4 mL

5.5 M

0.0187

 

2.0

 

V

43 mL

-

-

 

 

 

VI

2.510 g

-

-

 

 

 

VII

0.817 g

130.18

0.0063

 

 

(70%)

 

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

                  Prepared a suspension of 2.510 g of powdered 4A sieves and 0.315 g of L-DIPT in 43 mL of dry CH2Cl2.  Stirred; cooled to -23 C.  Added 0.250 g of Ti(O-i-Pr)4 followed by 3.4 mL of TBHP (5.5 M in isooctane).  After stirring for 1 h, 1.027 g of allylic alcohol I was added.  After 24 h the reaction mixture was warmed to 0 C and poured into a freshly prepared solution of 3.114 g of FeSO4-7H2O and 1.621 g of tartaric acid in 10 mL of H2O.  Stirred at 0 C for 10 min.  Poured 2-phase mixture into a separatory funnel and separated the layers.  The aqueous layer was filtered to remove insoluble material and extracted with 2, 50 mL portions of Et2O.  The combined organic layers were dried over MgSO4, filtered and the solvent was removed by rotary evaporation.  The product was isolated by flash chromatography on silica gel using 50:50 Et2O-hexanes as eluant.

 

1H NMR (CDCl3, 300 MHz) d 3.90 (ddd, J = 12.6, 5.5, 2.6 Hz, H2), 3.61 (ddd, J = 12.6, 7.3, 4.3 Hz, H3), 2.96 (ddd, J = 7.8, 5.5, 2.4 Hz, H1), 2.87 (m, H1), 1.78 (m, H4), 1.40 (m, H5), 0.95 (dd, J = 6.6, 3.4 Hz, CH(CH3)2).

 

notes

 

When the allylic alcohol is drawn in the above orientation, the use of L-tartrate will give the epoxide shown

When the allylic alcohol is drawn in the above orientation, the use of L-tartrate will give the epoxide shown.  D-Tartrate gives the opposite stereochemistry.  (E)-double bonds tend to react faster than the corresponding (Z)-double bonds.