Mild Procedure for Preparing Vinyldiazoacetic Acid Esters of Carbohydrate Acetonides

We described, herein, the preparation of new vinyldiazoacetic acid esters of carbohydrate acetonides(5b-g) in good to moderate yields. The key step of this procedure is the elimination reaction performed with a-diazo-b-hydroxy esters 4a-h by using trifluoroacetic anhydride and triethylamine as reagents. Thismethodology has some advantages over that one described in the literature (POCl3) for the preparation of suchkind of compounds. The use of trifluoroacetic anhydride, an easily available reagent, in mild reaction condition allows the preparation of the acid sensitive carbohydrate derivatives 5b-g without the detection of degradation products. The methodology can also be extended to the synthesis of other types of vinyldiazoacetic acid esters as it was shown for 5a and 5h.