Diketones Reformatsky reaction

Lanthanide -Diketonates as Diels-Alder Catalysts 8.3.5 Reformatsky Reactions... 

A case in point is cyclohexane-1,3-dione. This may be converted into a mono-dioxolan [227, 228], or into a mono-dithiolem or -oxathiolan [228]. The dioxolan is partially cleaved to the hydroxyethyl enol ether (with which it is in thermal equilibrium) by very dilute base, and it reverts to the diketone under more strongly alkaline conditions [227]. The free ketone group in these ketals can be made to react vtith various nucleophilic reagents such as phenyl lithium [228] and cyanide ion [227] and can also be subjected to the Reformatski reaction [227], but the yields in these reactions appear to be rather low. 

Symmetrical diketones react normally with either one (equation 12) ° or two (equation 13) equivalents of the Reformatsky reagent. There are no reports of selective reaction at a single carbonyl of an un-symmetrical substrate, although this has been accomplished by selective acetal protection (Scheme 5). ... 

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