Hello!

I'm not sure if this is what you're asking for, as it doesn't fit that line of code.  'LitT' is a data constructor not a type constructor.  So instead it'd be

reifyType (LitT ...) = ConE 'LitT ...

If this is what you're looking for, then 'lift' is what you want: http://hackage.haskell.org/packages/archive/th-lift/latest/doc/html/Language-Haskell-TH-Lift.html

In particular, I recommend using this package of template haskell orphans, rather than deriving your own: http://hackage.haskell.org/package/th-orphans

Hope that helps!
-Michael