okay, be warned, if you do this because your PSu isn't not configured for it, means it will likely produce problems and blow your psu and likely this even will take out other items in your computer such as motherboard, video card, ram and cpu.
Answering your question " a 2x SATA to 6-pin PCIE instead? " sure, and then do not be surprise if you destroy your computer.
Before you do anything why don't you tell use the make and model of cpu, motherboard, video card and power supply. and let us help you before you do something you will likely regret.