Regular expressions are an awesome tool, but unfortunately every language/environment has its own dialect, including Visual Studio.
Visual Studio uses {} to indicate a group to capture. A captured group can later be referenced by using backslash and the match number (one based).
As an example, let's say you want to do the following replacement:
// Original
var person = new Person("Frank");// Expected result
var person = new Person { Name = "Frank" };
To achieve this you can use the following search and replace patterns in Visual Studio:
Search pattern: var person = new Person\({:q}\);
Replace pattern: var person = new Person { Name = \1 };
:q is a special Visual Studio regex symbol for matching a quoted string. Another custom VS symbol is :z which matches an integer.