Strukturaufklärung eines Dimethylfulven‐Trimeren. Hinweis auf eine [6 + 4]‐Cycloaddition von 6, 6‐Dimethylfulven

Structure Elucidation of a Dimethylfulvene‐trimer. Evidence for a [6+ 4]‐Dimerization of 6, 6‐Dimethylfulvene Thermal reaction of pure 6, 6‐dimethylfulvene ( 1c ) at 60° gives an oligomeric mixture consisting mainly of fulvene‐trimers. The structure of the main product 3c is partially elucidated by 1 H‐NMR. investigations at 400 MHz and definitely confirmed by X‐ray analysis. The formation of 3c is explained in terms of a [6+4] dimerization, followed by a 1, 5‐proton‐shift and a final Diels‐Alder reaction.