Structural studies on dioxan-2-ylium ions; intramolecular attack of an oxygen atom on a carbenium ion centre

As models for the ionization of orthoesters, a series of 1,3-dioxan-2-ylium salts have been prepared and characterized. The properties of 1,3-dioxan-2-ylium hexachloroantimonate 1, 5-ethoxymethyl-1,3-dioxan-2-ylium hexachloroantimonate 2, 2-methyl-5-ethoxymethyl-1,3-dioxan-2-ylium hexachloroantimonate 3, and 2-phenyl-5-ethoxymethyl-1,3-dioxan-2-ylium hexachloroantimonate 4, have been studied by 1 H and 13 C NMR spectroscopy. The structures of 3 …