NMR experiments on acetals. 51. On the origin of the conformational behaviour of the trimethylammonium substituent: ‐N⁺Me₃substituted 1,3‐dioxanes and ‐CH₂N⁺Me₃substituted 1,3‐dioxolanes and 1,3‐dioxanes

Abstract

By a systematic investigation of -CH2N+Me3-substituted 1,3-dioxolanes and 1,3-dioxanesI together with other conformational peculiarities (axial preference of a 5-N+Me3 grouping in 1,3-dioxane) it is concluded that a C-N+ bond prefers to become parallel with (the) p-lobe(s) of a 8-heteroatom.In a previous paper (1) we reported on the conformation of some 2-CF -l,+ 3 dioxolanes, prepared following a kinetically controlled reaction (2). Conformational aspects of 4-CH2X-substituted 1,3-dioxolanes have been reported (1,3).We now wish to emphasize more specifically about the orientation of such CH2X-side-chains (X=Cl, NfMe3) in dioxolanes, but also in some CH2N+Me3-, and "Me, substituted 1,3-dioxanes, as the result of a further 'H-NMR study of a series of new compounds (Tahles I -11).