NMR Experiments on Ketals IX 1, 3‐Dioxanes with axial Alkyl Substituents

Abstract

Abstract PMR Spectroscopic evidence has been advanced ( 3 ) to prove that the fundamental conformation of 4‐ t . Bu‐4‐Me‐1, 3‐dioxane (I a ) is the stretched boat form (I b ). This paper discusses the PMR spectra of trans ‐4, 6‐dialkyl‐1, 3‐dioxanes, including trans ‐4, 6‐di‐ t . Bu‐1, 3‐dioxane a genuine boat conformation model. It is concluded that the features, which have led to the boat form I b , are not characteristic of stretched forms, but may be found in some chair form 1, 3‐dioxanes. It is shown that stretched forms do not contribute significantly to the properties of trans ‐4, 6‐dialkyl‐1, 3‐dioxanes.