The fullmoon maples (Acer shirasawanum) do very well in full sun as long as not the very yellow/gold colored ones ('Aureum', 'Autumn Moon', etc.). And should develop excellent fall color in a fair amount of sun. However, in hot summer climates, a little protection or shade from hot afternoon sun is never a bad thing :-)

I have a a palmatifolium in a pot and a crimsons queen in a pot. They get quite a lot of the punishing Australian sun. Enough shade too.

palmatifolium is coping much better no leaf scorch yet. The crimson queen has quite a bit of scorch.