Substitution of the acetoxy groups of dialkoxymethylacetates by organometallic reagents: a route to allyl-, propargyl-, homoallyl-, homopropargyl- and α-stannylacetals
The substitution of the acetoxy groups of dialkoxymethylacetates by organometallicreagents 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 organometallicreagents: soft nucleophiles with strong electrophilic assistance by the counterion are the best reagents. Allyl-, propargyl-
to give chloroethoxymethyltributyltin, which was easily transformed to ethoxymethyltributyltin by reduction with tributyltin hydride. Diethoxymethyltributyltin, a masked aldehyde anionic equivalent, was metallated with butyllithium, and the resulting new organolithium reagent was trapped with benzyl bromide, benzaldehyde, and cyclohexenone.