Ketones, fragmentation exercise

If the MeO group is replaced by a leaving group such as MsO, it can exercise the pull and the carbonyl can provide the push after it has been attacked by a nucleophile. This next five-membered cyclic ketone fragments on treatment with base—can you detect hints of the benzylic acid rearrangement ... 

Norrish Type II reactivity is often a common reaction path for ketones with available Y 7< °sens. Hydrogen abstraction by the excited carbonyl group results in the formation of a 1,4-biradical which can undergo either bond cleavage to reform the carbonyl group and an alkene or bond formation to yield a cyclobutanol derivative. The fragmentation path is followed by the ketone (13). The interest in this reaction is the control which can be exercised on the ketonization of the resultant enol (14). Apparently in the presence of (->-ephedrine asymmetric formation of the final product, (R)-2-methylindanone (15),... 

---