Analogy for the formation of V may be found in the earlier work of Reich and Cram'' who have demon- strated that thermal cleavage to biradical intermediates occurs in substituted [2.2]paracyclophanes, as in the isomerization of systems VI to VII. ... The mass spectrum shows a molecular ion peak at mje 308 and a base peak at mje 154. The ultraviolet spectrum (Figure 1) is strikingly similar to that of 1,4- dimethylnaphthalene and shows the typical batho- ...
