Please refer to the attachment.
I have attached a mechanism to this message which includes the structures of 'I' and 'J' - I hope it's all clear. Some points that I should highlight:
1. In the first step you form the enolate of the diester upon treatment with NaOMe. This reacts with the di-iodoalkane. Since there ...
This solution provides drawings for the products I and J in an attached Word file. The reactions which are included within this response include ester hydrolysis, decarboxylation, and tautomerism. This solution is also quite detailed and explains each step of the reaction.