Can I use Shimano STI brifter with 11 speed mountain derailleur? I'm considering a 1x drivetrain for a gravel bike. Shimano hasn't yet released a road/gravel solution to the market that incorporates a rear derailleur with a "clutch" (that keeps the chain from bouncing as much). Except for some of their mountain derailleurs, e.g. SLX. 

So my question is, is such an 11 speed Shimano derailleur compatible (i.e. same "pull" as) their 11 speed STI shifters (such as Ultegra 6800)?

I did find an answer for 9 speed Shimano, indicating compatibility, but I'd like to know about 11 speed.

Thanks!
No. The cable pull is different starting with 10spd mountain. In Shimano-land you presently do this with a Jtek Shiftmate 8, Wolf Tooth Tanpan, or other actuation ratio converting device. Using a di2 MTB RD with di2 STI also works. In either case there's not a great solution to the left lever being either mismatched or a heavy, expensive shifter sitting there not hooked up to anything. SRAM has three native 1x road groups with non-Doubletap lefts and clutch that get specced on all the bikes that actually come this way.

Edit: Another related setup presently available is the TRP Hylex di2 adaptor kit, which integrates a di2 climbing shifter with the right Hylex lever, which can then control an XT or XTR RD with clutch.