SUBSTITUTION OF THE ACETOXY GROUPS OF DIALKOXYMETHYLACETATES BY ORGANOMETALLIC REAGENTS - A ROUTE TO ALLYL-ACETALS, PROPARGYL-ACETALS, HOMOALLYL-ACETALS, HOMOPROPARGYL-ACETALS AND ALPHA-STANNYLACETALS

The substitution of the acetoxy groups of dialkoxymethylacetates by organometallic reagents has been examined in a search for new methods of preparing functional acetals. The efficiency of the substitution of the acetoxy group is highly dependent on the nature of the organometallic reagents: soft nulceophiles with strong electrophilic assistance by the counterion are the best reagents. Allyl-propargyl-, homoallyl-, homopropargyl- and alpha-stannylacetals have been made by this route, in which dialkoxymethylacetates often function as useful substitutes for dialkylphenylorthoformates.