It sounds like your coins were received directly to a pubkey (pay-to-pubkey), rather than an address (pay-to-pubkeyhash). You might have to spend them by building a raw transaction. Have you looked at tools such as coinb.in? It can be used offline by downloading the source. For your input you'd reference the receiving transaction ID and the output index (n).
It is possible?
Why not try it I don't know if it will work where did you hear that?
If you are going to make a raw transaction through coinb.in you need any of these Address, WIF key, Redeem Script or Transaction ID.
But I think your case about your private key will not work on Coinb.in
Can you post a sample of your private key I receive a PM from you and you said you have the private key why not import it into electrum?