Dear Mark,

Article 356/II of the Turkish Code of Obligations states that the work may be subcontracted to another person (in your case the second developer) if the work does not necessitate personal skill/craftsmanship (in your case it doesn't).

So the first developer may freely delegate the construction task to the second developer with an independent contract of work. Note that your consent is not required in this contract as you are not a party of it.

This situation works both ways. As you haven't entered into a contract with the new developer, you cannot claim anything from him, but also he cannot request any payment from you. His contract is with the first developer only. You've mentioned that your name is in the document between the first and second developers, and this is most probably just a reference to your development contract with the first developer. You needn't worry about this. You aren't a party of this second contract and not bound by it. As a result, the new developer (sub-contractor) cannot directly request anything from you. You can refer to the following Court of Cassation (Yargıtay) decisions on the matter:
"15. HD., Date:28.02.1974, E:145, K:166" and "4. HD., Date:15.09.1980, E:8100, K:9498".

Your answerer in this case is the first developer with whom you have a contract and you can base your claims on this contract. You cannot demand your payment from the new developer.

Also you have been mentioning "transferring the property to the new developer", which I find a bit ambiguous. Do you refer to the transfer of work (construction)? Is it perhaps a contract for construction rights in return for flat? You need to provide more data on the nature of the contract you call "purchase agreement" for us to help.