I am unsure what you are planning for.
If you're expecting the motherboard that you are running now to run DDR4 and be able to support an i5-6600k you'd be sorely wrong.
They both run very different chipsets and sockets.
The 6600K runs on LGA 1151
While the 3350P runs on LGA 1155
The 3350P doesn't support DDR4 or DDR3L.
The 6600K only supports DDR3L & DDR4.
Any motherboard running the LGA 1151 socket will be fine for the CPU, just make sure that it has overclocking enabled so that you can take full advantage of the chip.