Write down the steps and mechanism for preparing the target compound 108 below:

109. Analysis: We must first open the lactone ring: FGI Synthesis: No control is needed in the first step: there is only one enolisable H atom on either aldehyde. If we use malonic acid for the second step, cyclisation and decarboxylation will be spontaneous (Monatshefte, 1904, 25, 13). NH3,EtOH11000CH2(CO2H)2TM108 If you're not sure of the details of this last step, try working it out as a mechanistic