Red robin shedding leaves

Hi my red robin keeps shedding its leaves especially the red leaves
I pruned it last year and since I pruned it now it's shedding its leaves
I moved it out of the bright sun to a semi shade spot but it still made no difference
It's in a big pot but I was wondering if I should cut it down small to encourage new growth and plant what I cut off into pots or plant it at by back by the fence to form a hedge sending a pic
It had leaf spot but I sorted that and I examined it no bugs so what could be wrong

 

I'd suggest it needs a bigger pot or better still planted out.
It's probably a bit starved, I would imagine a plant that size would be a gross feeder right now.

 

I ask my son to dig a deep hole by the fence and plant it in the ground although it's semi shade spot there but cannot put it any where else I also take a cutting to repot thanks pete

 

I. Have just replanted it it looks nice maybe later it will branch out with less leaves falling