Ultegra 6800 chainrings and Claris r2000

Claris - https://bike.shimano.com/en-US/product/component/claris-r2000/FC-R2000.html

Ultegra - https://bike.shimano.com/en-US/product/component/ultegra-6800/FC-6800.html

They have the same PCD and chain line which are the two measurements that show you whether the chainrings will sit correctly. I would be surprised if they weren't compatible based on this but I'm not 100% sure they are so take this with a grain of salt. Their Q-factors are different but I doubt most people would notice 3.4mm difference.