Does this route work to synthesize cyclopentane from cyclohexane?
Elimination with strong base to form cyclohexene.
Ozonolysis to make di-aldehyde.
Oxidation to make di-carboxylic acid.
Esterification with ethanol, acid, and heat.
Alpha-proton elimination with ethoxide ion.
Intramolecular attack of other carbonyl carbon; loss of ethoxide leaving group.
Acid, high heat, water to return to carboxylic acid. Expulsion of ethanol.
Heat for decarboxylication. Loss of carbon dioxide.
Not illustrated: removal of carbonyl using Wolff-Kishner and Clemmensen.
I think a few modifications I could make are:
Formation of methyl ester using diazomethane. This would not involve heat and acid. But it would involve something that is potentially explosive.
Alternately, make an acid chloride and then go down to the ester if I wanted to avoid the heat involved with Fischer esterification.