Creating a list of rules from a list of integers

corey979 already gave the standard solution in the comments:

Rule @@@ Partition[{1, 2, 3, 4}, 2, 1]

{1 -> 2, 2 -> 3, 3 -> 4}

But this is also doable with rules like you tried. I'd do it like this:

{1, 2, 3, 4} //. {
  {a___, x_Integer, y_Integer, b___} :> {a, x -> y, y, b},
  {rules___Rule, _Integer} :> {rules}
  }

{1 -> 2, 2 -> 3, 3 -> 4}

BlockMap:

BlockMap[Apply@Rule, Range@4, 2, 1]

(* {1 -> 2, 2 -> 3, 3 -> 4} *)

Using Through, which I'm always looking for a reason to use, and rarely find one:

(Most -> Rest)@{1, 2, 3, 4} // Through // Thread

(* {1 -> 2, 2 -> 3, 3 -> 4} *)

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