Do these sentences mean the same thing?
1. I desire to do this.
2. Doing this is very interesting to me.
Please note my corrections above. You must end every sentence with an appropriate punctuation mark.
Sentence 1 is unnatural. We say "I want to do this". We usually follow "I desire" (when we use it at all) with a noun.
Sentence 2 is grammatical but fairly unnatural.
They definitely don't mean the same thing. You can want to do something even though it's not interesting. Something could be interesting but you might not want to do it.