Must be something in the climate this year. I have a 5 year old Japanese Maple that has been in the same bed for 4 years and did beautifully until about 3 weeks ago. Now the leaves are drying up and dropping (looks alot like your photos). Nothing has changed except we are having an unusually early hot dry summer. From reading older posts on this topic, I am hoping it is a watering issue. Thoughts anyone?

I can't tell from the pics--are the whitish lines dead leaves/branches on the tree or something on the ground below? I do see some leaf scorching. If possible, move the tree to a shadier spot and water more frequently. There is also product called Pro-tekt that helps a bit.

Here is a link that might be useful: Pro-Tekt

No, that's something on the ground.
Can I move the tree now or wait till fall/spring?

Is that a sunny spot?
The tree doesn't look to be mulched very well if at all to help retain moisture in the summer heat and it's planted in front of a brick wall. Can you say brick oven?

Don't attempt moving it now. Wait until the fall or better once the leaves drop.
In the mean time, if you have some patio screen mesh laying around that you can encircle around the tree just to give it a little break. Don't cover the top just give it some protection from the brick oven. And add 3" of natural mulch.

By the way, you will want to move it anyway as that's not enough space for a j maple. They don't stay that size foreever.

I think the partial problem is that the soil around the tree is kind of moisture most of the time: drainage problem.
So, it is absolutely wrong to move it now?

When I looked at the pics, I was thinking it was in a pot. Sorry about that. Mulch, yes, and don't water more frequently without digging down through the mulch and checking the soil with your finger to see if it has dried out. It's difficult to tell exactly how badly it's doing from the current pics. In theory, I'd move only as a last resort. If you do, choose the morning of a relatively cool day, keep the roots wet at all times, and move it to location with well draining soil, preferably shady.

What dsb said. ^^^ Only if you have to move it, i'd suggest evening before the relatively cool day.
Be sure to dig as much of a rootball as you can.