NMR experiments on acetals. Part 48 the prins‐reaction on cyclic (poly) olefins and the characterization of resulting 1, 3‐dioxanes

Abstract

We have investigated the Prins‐reaction of formaldehyde on several cyclic (poly) olefins. The nature (100 and 300 MHz NMR studies; table II) and yields of the resulting 1,3‐dioxanic compounds have been carefully assessed (Table I). The results indicate that most previous claims are to be taken only as general rules, with many exceptions however. Thus, a wide variety in stereospecificity of the primary reaction must be accepted, leading to syn and anti (diaxial) and even trans (diequatorial) addition routes. It seems acceptable that only protonated polymeric formaldehyde oligomers may rationalize such a broad spectrum of possibilities.