One of the important reactions of benzylic alcohols, ethers, and esters is the ease of cleavage of the benzyl-oxygen bond during hydrogenation. This is another example of "hydrogenolysis," the cleavage of a bond by hydrogen. It is facilitated by the presence of acid. Hydrogenolysis can also occur with strained-ring compounds. On hydrogenation of compound $\mathbf{D}$ (sce below) using Raney nickel catalyst in a dilute solution of hydrogen chloride in dioxane and water, most products have a 3,4 -dimethoxyphenyl group attached to a side chain. Among these, an interesting product is $E$, whose formation illustrates not only hydrogenolysis but also the migratory aptitude of phenyl groups. For product E, these are key spectral data: MS $(m / z): 196.1084$ (M $^{\pm}$, at high resolution), 178 IR $\left(\mathrm{cm}^{-1}\right): 3400$ (broad), 3050,2850 (CH $_{3}$ - O stretch) $^{1} \mathrm{HNMR}\left(\delta, \text { in } \mathrm{CDCl}_{3}\right): 1.21(\mathrm{d}, 3 \mathrm{H}, \mathrm{J}=7 \mathrm{Hz}), 2.25(\mathrm{s}, 1 \mathrm{H}), 2.83(\mathrm{m}, 1 \mathrm{H}), 3.58(\mathrm{d}, 2 \mathrm{H}, \mathrm{J}=7 \mathrm{Hz}), 3.82(\mathrm{s}, 6 \mathrm{H}), 6.70(\mathrm{s}, 3 \mathrm{H})$ What is the structure of compound E?
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